This chapter provides a foundation for the remainder of the report. It summarizes current knowledge regarding young adulthood as a critical developmental period in the life course; highlights historical patterns and recent trends in the social and economic transitions of young adults in the United States; reviews data on the health status of the current cohort of young adults; briefly summarizes the literature on diversity and the effects of bias and discrimination on young adults’ health and well-being; presents the committee’s key findings and their implications; and enunciates several key principles to guide future action in assembling data, designing research, and formulating programs and policies pertaining to the health, safety, and well-being of young adults. Many of the topics summarized in this chapter are discussed in greater depth in subsequent chapters.
Biologically and psychologically, young adulthood is fundamentally a period of maturation and change, although the degree of change may seem less striking than the changes that occurred during childhood and adolescence. As just one example, the physical changes of the transition from childhood into adolescence are transformative, with bodies growing in dramatic bursts and taking on secondary sex characteristics as puberty unfolds. As young people move from adolescence into adulthood, physical changes continue to occur, but they are more gradual. Individuals begin the steady weight gain that will characterize adulthood, but these changes
are not as discontinuous as they are at the beginning of adolescence (Cole, 2003; Zagorsky and Smith, 2011).
In some ways, the tendency for the developmental change that happens during young adulthood to be gradual instead of dramatic may have led to the devaluation of young adulthood as a critical developmental period, but that developmental change should be not be underestimated. It is integral to transforming children and adolescents into adults. The psychological and brain development that occurs during young adulthood illustrates this point.
Over the past two decades, research has elucidated some of the key features of adolescent development that have made this period of the life course unique and worthy of attention. These insights, in turn, have helped shape policy in major ways. These adolescent processes, and the increasing scientific and public attention they have received, provide a reference point for understanding the developmental importance of young adulthood.
In general, adolescence is a complex period characterized by substantial cognitive and emotional changes grounded in the unfolding development of the brain, as well as behavioral changes associated with basic psychosocial developmental tasks. In particular, adolescents are faced with the task of individuating from their parents while maintaining family connectedness to facilitate the development of the identities they will take into adulthood. At the same time, the overactive motivational/emotional system of their brain can contribute to suboptimal decision making (Crosnoe and Johnson, 2011). As a result, many adolescents tend to be strongly oriented toward and sensitive to peers, responsive to their immediate environments, limited in self-control, and disinclined to focus on long-term consequences, all of which lead to compromised decision-making skills in emotionally charged situations (Galván et al., 2006; Steinberg et al., 2008). This combination of characteristics is implicated in the heightened rates of risky behaviors and accidental death among adolescents (and young adults) relative to childhood and later stages of life, and awareness of these issues has reshaped policy responses to adolescent behavior in general and crime in particular (as described in the National Research Council  report on juvenile justice).
Clearly, much social, emotional, and cognitive maturation needs to occur before adolescents are capable of taking on adult responsibilities and their many behavioral risks decline to adult-like levels. The ongoing development that occurs during young adulthood is what marks the transition from adolescence to adulthood. Again, this development is not necessarily discontinuous (such as the notable surge in risk taking that occurs during
the transition from childhood into adolescence), but instead, it takes a more gradual and linear form, less obvious perhaps but no less important. Although findings from studies that directly compare adolescents and young adults on various cognitive tests and decision-making tasks are by no means uniform, the available research documents the slow and steady progress in self-regulation and related psychological capacities that takes place as adolescents transition into their 20s (see Cauffman et al., 2010). Compared with adolescents, young adults
- take longer to consider difficult problems before deciding on a course of action,
- are less influenced by the lure of rewards associated with behavior,
- are more sensitive to the potential costs associated with behavior, and
- have better developed impulse control.
In other words, the differences between adolescents and adults are stark, and the years between 18 and 26 are when young people develop psychologically in ways that bridge these differences. This development reflects many things, including the opportunities young people have to take on new roles and responsibilities and changes in their social contexts. It also reflects the similar gradual development of their brains.
The process of structural and functional maturation of the brain through adolescence to adulthood has garnered a great deal of attention, as neurobiological processes are believed to stabilize before declining with age. Maturation is of particular interest given the role of plasticity in affording opportunities for specialization, but also posing risks for abnormal development. Developmental neuroscientists, however, have traditionally assumed that adulthood is reached by age 18—hence the predominance of neurodevelopmental studies that compare children (under age 12) and adolescents (approximately 12-17) with adults (18-21 or extending and averaging through the mid-20s to the 30s). This approach has revealed many immaturities during the adolescent period, but much less is known about young adulthood. Discussions recently have emerged of the possibility of a prolonged brain maturational trajectory through young adulthood, as described below. Although the most significant qualitative changes in brain maturation have been found to occur from childhood to adolescence, emerging evidence does suggest that specialization of brain processes continues into the 30s, supporting both cognitive and motivational systems.
The primary mechanisms underlying brain maturation through adoles-
cence into adulthood are synaptic pruning, myelination, and neurochemical changes. Synaptic pruning refers to the programmed elimination of synaptic connections between neurons believed to support specialization of brain processes based on experience. After a proliferation of synaptic connections through childhood, when the gray matter thickens, a decline in synaptic connections occurs through adolescence (Petanjek et al., 2011) and is believed to contribute to the thinning of gray matter that proceeds through adolescence (Gogtay et al., 2004). Magnetic resonance imaging (MRI) studies, which provide in vivo measurements of gray matter thickness, have focused predominantly on immaturities during adolescence and have considered adulthood to be established by the early 20s (Gogtay et al., 2004). MRI studies that sample a wider age range, however, indicate a prolonged period of gray matter thinning of prefrontal cortex that persists through the third decade of life (Sowell et al., 2003; see also Figure 2-1). Similar maturational trajectories have been observed in human postmortem studies that indicate a continued decrease in synaptic connections in the prefrontal cortex into the 30s (Petanjek et al., 2011). The prefrontal cortex is the region that supports abstract reasoning and planning. Through its extensive connectivity throughout the brain, it also supports executive function, providing control and modulation of behavior (Fuster, 2008). It plays a major role in decision making, and its maturation is believed to support cognitive development (Fuster, 2002; Luna, 2009).
Notably, despite continued specialization in the prefrontal cortex through the 20s, its engagement during executive tasks can appear adult-like as early as adolescence. Functional MRI (fMRI) studies of executive control through adolescence report both greater and lesser engagement of lateral prefrontal regions known to play a primary role in executive function (Luna et al., 2010). A recent longitudinal study was able to characterize developmental changes in core cognitive components of the ability to suppress impulsive responses by measuring the ability to stop a reflexive eye movement (Ordaz et al., 2013). Results suggest a decrease in prefrontal engagement through childhood stabilizing by adolescence. However, recruitment of the anterior cingulate cortex, a medial prefrontal region that is distinct from other prefrontal regions in supporting performance monitoring and error processing, increases during executive function processing through adolescence and young adulthood (Ordaz et al., 2013). These results suggest that processes distinct from prefrontal executive function that support monitoring behavior underlie cognitive development and continue to mature through young adulthood. The implication is that by young adulthood, prefrontal executive processes are at adult levels, but processes involved in monitoring behavior are still improving, which may affect decision making.
In addition to the maturation of prefrontal systems that support ex-
FIGURE 2-1 Continued maturation of prefrontal cortex through young adulthood evidenced from (A) in vivo MRI results showing thinning of cortical gray matter in prefrontal cortex and (B) postmortem evidence showing continued loss of synapses in prefrontal cortex into the 30s.
SOURCES: (A): Adapted from Sowell et al., 2003; (B): Petanjek et al., 2011; reprinted with permission.
ecutive function, motivational and emotional brain systems in limbic areas show a protracted development through adolescence and young adulthood. The striatum is a limbic region rich in dopaminergic innervation. Dopamine is the neurotransmitter that supports motivation and reward processing (Cools, 2008). Through its connectivity with prefrontal systems, it pro-
vides motivational modulation of behavior. MRI studies indicate that the striatum peaks in gray matter growth at an even later time than cortical regions through adolescence (Raznahan et al., 2014; Sowell et al., 1999; Wierenga et al., 2014). In addition, animal studies suggest a peak in the availability of dopamine, believed to play a role in increased sensation seeking beginning in adolescence (Padmanabhan and Luna, 2013; Spear, 2000; Wahlstrom et al., 2010). fMRI studies typically show a peak of increased recruitment of the striatum during monetary reward tasks in adolescence that decreases through young adulthood (Galván et al., 2006; Geier et al., 2010; van Leijenhorst et al., 2010). In particular, the presence of peers has significant salience in adolescence, engaging the reward circuitry to affect decision making (Chein et al., 2011). The trajectory of changes in reward processing through young adulthood, however, has not been directly investigated and in fact some studies have used young adults to represent all adults (van Leijenhorst et al., 2010). It is possible that developmental declines in striatal activity in response to rewards may be lower in young adulthood than in adolescence but still be greater than in later adulthood. Similarly, the amygdala, which supports emotional processing, has a peak in gray matter growth in the teen years, with a subsequent decrease in volume (Greimel et al., 2013; Scherf et al., 2013). The amygdala shows greater functional reactivity to emotional stimuli in adolescence (Blakemore, 2008; Hare et al., 2008), which may persist through young adulthood. Animal studies indicate that white matter fibers between the amygdala and cortex continue to increase into young adulthood (Cunningham et al., 2002). Despite this increase in structural connectivity, however, human neuroimaging indicates decreased functional connectivity into young adulthood, suggesting developmental increases in regulatory development with regard to the effects of emotion processing on behavior (Gee et al., 2013).
In parallel with decreases in gray matter in prefrontal and striatal regions are increases in white matter brain connectivity, which supports the ability for prefrontal executive systems to modulate reward and emotional processing. Postmortem studies indicate continued myelination—insulating of white matter connections—through adolescence and adulthood throughout cortical regions, including prefrontal systems (Lebel et al., 2008). Diffusion tensor imaging, which measures the integrity of white matter connections in vivo, indicates a hierarchical maturation of white matter, with tracts connecting cortical and limbic regions showing protracted development through adulthood (Lebel et al., 2008; Simmonds et al., 2013). During childhood to adolescence, a peak in white matter growth occurs throughout the brain, with continued growth of tracts as they reach cortical and limbic gray matter in young adulthood (Simmonds et al., 2013). Last to mature are the cingulum and uncinate fasciculus, which provide connectivity between cortical and limbic regions. The cingulum integrates dorsal frontal cognitive
(e.g., anterior cingulate supporting performance monitoring) and limbic regions supporting emotion processing that continue to mature through the early 20s (Simmonds et al., 2013). The uncinate fasciculus, which integrates ventral frontal cortical (e.g., orbitofrontal cortex supporting motivation), amygdala (supporting emotion), hippocampus (supporting memory), and temporal cortical regions that form a circuit underlying socioemotional processing, continues to mature through the 20s (Simmonds et al., 2013). During young adulthood, therefore, connectivity that supports socioemotional processing is still immature but developing compared with later adulthood.
Within these maturation processes are unique gender differences that emerge in adolescence, are believed to be associated with earlier puberty in girls than in boys, and continue to dissociate through adulthood (Dorn et al., 2006; Ordaz and Luna, 2012). Young men have larger total brain volume, females show earlier cortical thinning and maturation of white matter integrity (Lenroot et al., 2007; Simmonds et al., 2013), and males show greater change in limbic regions (Giedd et al., 1997; Raznahan et al., 2014). These differences are believed to underlie gender differences in the emergence of different psychopathologies, including female predominance of depression and male predominance of antisocial personality disorders.
Taken together, the evidence demonstrates continuing maturation of limbic systems supporting motivation and reward processing and prefrontal executive systems. It has been proposed that the relative balance of maturation of motivational systems and prefrontal executive processing underlies the adolescent sensation seeking already discussed (Ernst et al., 2006; Smith et al., 2013; Somerville and Casey, 2010). In young adulthood, this imbalance diminishes but is still present. Brain systems supporting motivational and socioemotional processing are still maturing in young adulthood, influencing a more developed prefrontal executive system capable of more sophisticated and effective planning and resulting in unique influences on decision making, such as adaptive choices or risk-taking behavior. Overactive motivational systems may drive adult-like access to cognitive systems, resulting in planned responses that are driven by short-term rewards. Indeed, greater sensation seeking often persists into the mid-20s. This profile of decision making may also affect the attention given to choices regarding health, profession, and relationships, which are addressed in this and later chapters.
The Developmental Bottom Line
Overall, critical developmental processes clearly occur during young adulthood. Initial findings suggest that mature aspects of executive functioning are paired with continuing increased motivational/emotional influences affecting decision making. Still, more work is needed to fully
understand young adulthood as a biologically and psychologically distinct and critical period of development and to relate these neurological changes to behavioral and social changes that typically occur during this period. Although these processes of maturation may sometimes appear as limitations on optimal decision making in young adulthood, the enhanced motivational processing that also occurs during this period plays an important adaptive role in supporting optimal learning and the ability and impetus to explore the environment and novel experiences.
The important psychological development experienced by young adults has not changed dramatically across generations, but their social functioning has (Steinberg, 2013). Social and behavioral scientists frequently discuss such social functioning in terms of five major role transitions of young adulthood—leaving home, completing school, entering the workforce, forming a romantic partnership, and transitioning into or moving toward parenthood (Schulenberg and Schoon, 2012; Shanahan, 2000). The focus on these social roles as the benchmark against which young adults from diverse segments of the population are compared can be critiqued as classist, ethnocentric, and heteronormative. These critiques certainly need to be acknowledged, but these role transitions do provide a useful structure for organizing the present discussion of young adulthood in the United States, especially if the significant diversity in these transitions among U.S. youth—both historically and in the contemporary era—is highlighted.
Two basic concepts—the timing and the sequencing of role acquisition—capture how the transition to these adult roles is taking more time and becoming more unpredictable (Settersten and Ray, 2010).
First, the timing of role acquisition in young adulthood is changing. In the long view, today’s U.S. young adults are taking less time to undergo these role transitions relative to young adults in the distant past. Relative to more recent cohorts, however, they are taking more time. The timing of role acquisition is affected by, among other things, economic development and state investments that impose various signifiers of life transitions, such as legal rules on when youth are granted various privileges and allowed to enter certain statuses or, alternatively, when they age out of services or other protections (Modell et al., 1976; Shanahan, 2000).
Second, the sequencing of role acquisition (i.e., the order in which various roles are assumed) also is changing. Configurations of young adult statuses may change across cohorts. Recently, more diverse combinations of statuses have led to a “disordering” of the transition into adulthood, a term that seems pejorative but is not bad or good per se. The sequence of the roles assumed in the transition to adulthood increasingly is shaped by
individual choices and actions rather than social structures. As discussed below, for example, young people partner and parent in different sequences because they have the freedom to do so now that the social stigma of nonmarital childbearing has diminished, and because economic or policy factors make various sequences more appealing and feasible than they used to be (Fussell and Furstenberg, 2005; Lichter et al., 2002; Rindfuss et al., 1987).
For many young adults, a major event is leaving the parental home to reside independently or with others of the same age. In some ways, leaving home is a rite of passage, which is why one main topic of interest concerning modern young adults in general and young adults during the Great Recession in particular is “boomerang” children—young adults who leave home to live independently but come back to reside with their parents (Stone et al., 2013). In truth, young adults living with their parents1 in moderate to large numbers is not a new phenomenon in the United States or in other industrialized societies, and doing so is not inherently problematic or beneficial. In the United States, 32 percent of young adults aged 18-31 lived at home with their parent(s) in 1968, in 1981 31 percent did, and in 2012 36 percent did (Fry, 2013). How people assess young adults living with their parents instead of with peers or alone often reflects how they perceive (or misperceive) the past, including their own personal histories (Settersten and Ray, 2010; Stone et al., 2013).
Beyond leaving the parental home, many other noteworthy family events occur in the lives of today’s young adults. In assessing the historical relevance of these contemporary patterns, one must keep in mind the importance of the comparison point. As with leaving home, contemporary young adult behaviors and statuses often seem so striking because they are viewed in the context of the post–World War II era, especially the 1950s. This era, however, was something of a historical outlier. What is going on today with young adults—especially in relation to family roles and responsibilities—appears to be less divergent, although still divergent, when compared against the full scope of the 20th century (Coontz, 2000).
Partnership and parenting are the core of family formation in the United States (see Chapter 3). How partnership is defined and how it connects to parenting have both evolved considerably in recent decades. Traditionally, partnership was defined in formal (i.e., legal) terms as marriage, especially among the white middle class. Today, partnership in young adulthood is most often viewed as a sequence from cohabitation—living with a
1 Young adults may live with one or both parents.
romantic partner—to marriage (a transition from an informal to a formal partnership widely recognized by laws) or just as cohabitation itself. While most young Americans see cohabitation as a precursor to marriage, this has not always been the case. Many immigrant families from Latin America, for example, have a long tradition of cohabitation as a form of marriage, but the practice of cohabitation as a step toward marriage is new for most groups (Cherlin, 2009).
Figure 2-2 shows the percentages of young adults having engaged in at least one of three family formation behaviors—cohabitation, marriage, and parenting—by age 25 by gender, race/ethnicity, and level of education (high school or college graduate). In total, just under two-thirds of young adults have made at least one of these three family role transitions by age 25 (Payne, 2011). This proportion, however, fluctuates across the population. A larger proportion of women than men have made at least one of these role transitions (69 percent versus 53 percent), and family formation is less common among young adults who are white (59 percent) than among those who are not (66 percent for African Americans and 64 percent for Latino/as). There is also an educational gradient to family formation in young adulthood, with family role transitions becoming less common as
FIGURE 2-2 Percentage of young adults in the United States with at least one family formation behavior by age 25.
NOTE: The dotted line represents the overall sample average (61 percent).
SOURCE: National Longitudinal Study of Youth 1997 (see Payne, 2011).
educational attainment rises. Indeed, college graduates are the only segment of the population in which less than a majority of young adults have made at least one of the three family role transitions. Of these three transitions, the most common is cohabitation (47 percent), followed by becoming a parent (34 percent) and marrying (27 percent) (Payne, 2011).
One important caveat to keep in mind when considering these family formation patterns is that historically, tracking the family formation behaviors of lesbian, gay, bisexual, and transgender (LGBT) people has been exceedingly difficult. Because sexual relations between people of the same gender were outlawed in many states until recently, identifying the LGBT population was a challenge. Only within the past decade have same-sex couples been legally allowed to marry, and they may do so even now only within a minority of states (although the number is growing quickly). Thus, many LGBT young adults would have been classified as cohabiting in the past simply because they were legally barred from marrying. Moreover, innovations in reproduction technology and changes in adoption laws (domestically and internationally) have enabled these young adults to become parents without having to engage in an opposite-sex partnership before entering a same-sex partnership—long the most common path to parenthood for gays and lesbians. In states where same-sex marriage is legally recognized, same-sex parents are demonstrating patterns of union formation (and dissolution) similar to those of opposite-sex parents (Hunter, 2012; Parke, 2013; Seltzer, 2000).
In terms of timing, family formation is clearly showing signs of becoming a longer-term process. In short, young adults are taking more years to partner and become parents than they did in the past, especially compared with the last half of the 20th century. Today, the median age at first marriage—the age by which half of the population has married—is just under 27 for women, a nearly 5-year increase over the past 30 years and extending beyond the 18-26 age range used to define young adulthood in this report (Arroyo et al., 2013). A similar trend has occurred among men, although their median age at marriage has consistently been a year or so higher than that of women. This trend often is discussed in terms of “delay,” but it is better thought of as part of the prolonged family formation process overall. As Americans live longer, they take more time to reach life-course milestones such as marriage. The transition to parenthood also tends to occur later in the life course, although the increase in median age at first birth over the last three decades has been less pronounced than the increase in median age at first marriage—about 3 years rather than 6 and just within our focal 18-26 age range (Arroyo et al., 2013).
These differences in the magnitude of the age increase in major family role transitions also speak to sequencing, or the growing tendency for transitions to cluster in heterogeneous ways. For most of American history
(especially among the white middle class), marriage preceded parenthood. Yet the lesser increase in age at first birth compared with age at first marriage resulted in the two trends eventually converging (in 1991, to be precise). Since that point, median age at first marriage has been older than median age at first birth (Arroyo et al., 2013). The sequence (or order) of these transitions has become less predictable.
Breaking down partnerships into cohabitation and marriage when discussing major family role transitions of young adulthood also reveals evidence of changing sequencing. In line with the increasing prevalence of cohabitation in the population at large, the proportion of young adults who have cohabited by the age of 25 (47 percent) is higher than the proportion of young adults who have married (27 percent) (Payne, 2011). Three-fifths of all young adults who are married cohabited first, lending credence to the idea that cohabitation is now the modal pathway to marriage. Furthermore, one-third of young adults with children became parents before marrying or cohabiting. Just as with overall family formation patterns, these specific family patterns differ by gender, race/ethnicity, and educational attainment. For example, marriage without cohabitation is more common among whites and college graduates, but becoming a parent without partnering is far less common in these same two groups (Payne, 2011).
Overall, young adults (including LGBT young adults) in the United States are taking more time before entering into family roles that have long defined adulthood compared with their parents and grandparents, and they are sequencing these roles in multiple ways. This is particularly true for youth from white middle-class backgrounds.
The transition from student to worker is a defining feature of young adulthood, given that Americans widely view financial independence from parents as a marker of becoming an adult. Yet young people are taking longer to become financially independent, and their school-work pathways are becoming more complex (Settersten and Ray, 2010). As with family formation, changes have been occurring in the timing and sequencing of the socioeconomic aspects of young adult role transitions. Chapter 4 gives a detailed accounting of how young people are faring in the educational system and in the labor market, but we highlight a few patterns in school-to-work transitions here in the context of the overall importance of studying young adults today.
Beginning with education, more young adults than in the past have been entering higher education in recent decades, but they are participating in higher education in many different ways and following diverse pathways (Fischer and Hout, 2006; Goldin and Katz, 2008; Patrick et al., 2013).
According to data from the National Longitudinal Study of Youth, in the United States, 59 percent of young adults have enrolled in some form of higher education by the time they reach age 25 (Payne, 2012). The overwhelming majority enrolled right after leaving high school, around age 18. Of those who enrolled, 33 percent enrolled in 2-year colleges and 44 percent in 4-year colleges and universities, with the remainder enrolling in both (Payne, 2012).
Of course, enrollment is not the same as graduation. The reality is that many young adults who enroll in higher education fail to earn a degree, at least while they are still young adults. Indeed, rates of completion of higher education in the United States have declined even as rates of enrollment have increased (Bailey and Dynarski, 2011; Bound et al., 2010), at least in part because enrollment rates have risen over time among those with less academic preparation in the K-12 years.
As with family role transitions, higher education patterns vary considerably across diverse segments of the population (Brock, 2010). Enrollment rates in both 2- and 4-year colleges are higher for women than for men and for whites than for nonwhites (Holzer and Dunlop, 2013; Payne, 2012). In fact, enrollment figures are at about 50 percent for African American and Latino/a young adults by the time they reach age 25 (compared with the population figure of 59 percent noted above), with even greater gender differences within these groups (Payne, 2012). The starkest disparities across these groups appear in graduation rates from 4-year colleges and universities, with women earning more bachelor’s degrees than men and whites earning more bachelor’s degrees than minorities (Payne, 2012). There are also growing disparities in educational attainment between young adults from poor and middle/upper-income families.
Thus, modal or average patterns of higher education enrollment and completion during young adulthood typically subsume a great deal of heterogeneity. This heterogeneity is clearly evident in the growing immigrant population, as many first- and second-generation immigrants have rates of college enrollment and graduation higher than those of the general population, while other immigrant groups (e.g., unauthorized immigrants, the children of Mexican immigrants) are significantly underrepresented in higher education (Baum and Flores, 2011).
Turning to employment, the increased enrollment of young adults in higher education has had a major impact on employment rates, as educational commitments often preclude substantial work commitments. Yet even taking into account the substitution of education for employment in the late teens and early 20s, a key feature of the employment status of young adults is unemployment, or being out of work when one wants to be working. Indeed, the unemployment rate for the under-25 population is twice that of the general population (Dennett and Modestino, 2013). This
elevated unemployment among young adults is not altogether new; they have always struggled more than older adults to find and hold onto jobs. Still, this age-related disparity in unemployment has been growing in recent decades, and it has become especially marked since the start of the Great Recession in late 2007. Across all education levels and school enrollment statuses, young adult unemployment has increased significantly in the last several years relative to pre-recession years (Dennett and Modestino, 2013). Furthermore, among those who obtain jobs, many earn considerably less than similar demographic groups did in the past.
Another school-work scenario is “idleness”—when young adults are neither enrolled in higher education nor employed for pay. Many idle young adults are not just unemployed but have dropped out of the labor force altogether, sometimes for very long periods of time, in response to the lower wages and benefits now available to those with high school or less education, especially among young men (Dennett and Modestino, 2013). As discussed in Chapter 4, rates of idleness and labor force nonparticipation tend to be higher (and are becoming more so) for young African American men, who have been hit harder than other groups by broad changes in the economy and the labor market (Dennett and Modestino, 2013). Their lack of employment activity often becomes reinforced over time if they have a criminal record or if they are in arrears on child support they have been ordered to pay as noncustodial parents.
The sequencing of education and employment in young adulthood also is changing in important ways. A traditional school-work path was college enrollment and graduation in the late teens and early 20s, followed by full-time entry into the labor market in the mid-20s (with some pursuing more education and pushing back full-time employment). This primarily unidirectional path is related to higher economic returns throughout adulthood. Another traditional path was bypassing higher education altogether to enter the labor market directly after secondary schooling, a path related to higher earnings than those of other young adults in the short term but lower earnings in the long term.
In the contemporary economic climate of stagnant or lower real wages and generally higher costs of financing education (despite the rising availability of federal Pell grants to help low-income students pay for college), more young adults are trying to participate in higher education and employment at the same time or moving back and forth between the two. These mixed or bidirectional paths—which tend to be more common among young adults from more socioeconomically disadvantaged backgrounds—are one of several explanations for the lower odds of completing higher education among low-income or minority students (Bernhardt et al., 2001; Goldin and Katz, 2008).
Overall, young adults in the United States are attempting to gain more
education, and more education improves employment prospects during young adulthood and beyond (not to mention affecting many nonemployment outcomes, such as civic engagement; see Chapters 4 and 5). Yet an unstable economic context and the high immediate costs of financing higher education mean that the process of gaining human capital to improve future job prospects and realize other benefits of education is not so simple, especially for some young adults from more disadvantaged socioeconomic and racial/ethnic groups.
Young adults’ successes or failures in education and employment are integrally linked to their health. In general, the more educated a young adult becomes, the healthier she or he will be in adulthood, whereas lower educational attainment and occupational success is associated with poor health status, and involuntary loss of employment can have a negative impact on both physical and behavioral health. But the causal direction is also reversed in many cases: young adults with disabilities and chronic health conditions may find it significantly more difficult to obtain higher education and employment.
General physical and psychological development and the transition to major family and socioeconomic roles are personal experiences of individual young adults. Yet how these developmental and social processes unfold—and their timing and sequencing—is shaped by broader societal and historical forces (Shanahan, 2000). In other words, what is happening among young adults today reflects the larger context in which they find themselves, through no choice or fault of their own.
First, the U.S. economy has undergone substantial restructuring over the last several decades in ways that have radically altered the landscape of risk and opportunity in young adulthood. The traditional manufacturing and blue-collar sectors of the economy have shrunk, while the information and service sectors have grown. Even within these sectors, earnings inequality has increased dramatically, both across and within occupational categories. There are now broad strata of secure and stable professional and managerial jobs with benefits at the top of the labor market, and broad strata of insecure and unstable jobs with low wages and virtually no employer-provided benefits at the bottom (although these low wages can often be supplemented by a range of tax credits and publicly provided health care and child care benefits). The middle of the earnings distribution has diminished somewhat, however, especially in the production and clerical job categories that used to be accessible to high school graduates (and even dropouts in the manufacturing and blue-collar sectors).
As a result, the returns to higher education—how much more one earns over a lifetime by getting a college or graduate degree—have risen to historic levels, especially in specialized fields that support high-growth sectors of the economy. Increasingly, the way to achieve a middle-class level of earnings is to develop human capital by staying in school longer. A high school diploma, which used to be a ticket to the middle class, does not support mobility as it did in the past (Bernhardt et al., 2001; Goldin and Katz, 2008; Schneider, 2007); most jobs now require at least some postsecondary education or training, if not a bachelor’s degree or higher. At the same time that the benefits of college enrollment have increased, however, the financial costs of enrolling (and staying enrolled) also have increased, as discussed in Chapter 4. Moreover, more students attend college without sufficient academic preparation and with very little knowledge or information about the world of colleges and universities. As a result, higher education is more economically necessary but also more difficult to attain for many young adults than in past decades.
Second, these socioeconomic changes have been accompanied by evolving norms and values regarding when young adults are expected to become independent of their parents and begin families of their own (Johnson et al., 2011; Roisman et al., 2004). Observers of modern social trends have noted that contemporary parents believe that their active parenting role extends further into their children’s life courses than was the case for parents in the past (Fingerman et al., 2012). This new conceptualization of active and involved parenting as something that filters into children’s 20s (and beyond) is often referred to as “helicopter” parenting (Fingerman et al., 2012). At the same time, Americans are less likely to view the early 20s as an appropriate time for family formation, especially having children, and young adults themselves tend to view marriage as unsuitable for this period of life (Teachman et al., 2000). Although this change in age norms has been most pronounced among the white middle class, it has pervaded diverse segments of the population in a process of cultural diffusion. Of course, changing age norms reflect changing behaviors (i.e., ideas about appropriate ages for a family transition change as people start making that transition at later ages), but age norms also shape how people view family transitions and, therefore, when they feel ready to make them (Cherlin, 2009; Teachman et al., 2000).
These macro-level trends are, of course, related. For example, the rising returns to and costs of higher education and the insecurity of the labor market for new workers mean that young people often concentrate on school and work in their late teens and early 20s rather than committing to a partner or starting a family. In this way, the economic changes that shape schooling and work alter age norms about family formation. This impact appears to be greater for marriage than for cohabitation or parent-
ing, as many young adults have high economic standards for entering marriage that do not apply to these other family transitions (Edin and Kefalas, 2005; McLanahan, 2004). An economic consequence becomes a cultural influence. As discussed in Chapter 3, these trends are also raising questions about parental obligations to provide financial support for education and other costs during this transitional period.
Overall, young adults now focus more on socioeconomic attainment than on family formation, which is lengthening the time to financial independence and keeping them tied to their families of origin. For youth from socioeconomically advantaged backgrounds, this period can then become a time of freedom and exploration. For youth from more disadvantaged backgrounds, there is a higher potential for stagnation, with supposed freedoms masking scarcer opportunities and cultural norms and economic realities not always being well aligned (Arnett, 2004; Furstenberg, 2010). Both the timing and sequencing of young adult experiences, therefore, reflect the macro-level contexts in which young people are embedded and are closely connected to where they came from and where they are going.
A third important component of social change with implications for social roles and how they interact involves the advances in information technology in recent years. This technological revolution has reshaped American society as a whole and has been acutely felt among and driven by young adults. According to national data from the Pew Research Center, virtually all young adults use the Internet on a fairly regular basis, and nearly all have cell phones and use social media (Lenhart, 2013). Moreover, racial/ethnic and socioeconomic disparities in rates of usage are not large. In fact, information technology and social media pervade most aspects of daily life among most young adults (Lenhart, 2013). They are a central feature of school and work activities, keep young adults in closer contact with their parents compared with prior generations, allow young adults to greatly expand the reach of their social networks, serve as an increasingly popular venue for dating and union formation, provide new ways to increase health care access (and to improve health care delivery and facilitate the monitoring of personal health), and serve as a new context for political socialization and civic engagement (Chan-Olmsted et al., 2013; Clark, 2012; Kreager et al., 2014; Turkle, 2011; Wegrzyn, 2014). Indeed, young adults are driving much of the innovation and growth of social media (Lenhart, 2013). Consider a recent Harvard Business Review analysis (Frick, 2014), which reports that the modal age of founders of billion-dollar Silicon Valley startups is 20-24. Thus, young adults are both consumers and creators of the new media, and the ways in which they move toward, take on, and function within adult roles are changing as a result—a theme that is revisited repeatedly in subsequent chapters.
Thus far, the general developmental processes of young adulthood (unique in the life course if not historically specific) and the social activities and roles of young adulthood (unique in the life course and historically specific) have been discussed separately, but in reality, they are intertwined. One way to see this intertwining is to consider the health and health behaviors of young adults, which have physical, psychological, social, and structural underpinnings (Johnson et al., 2011).
Developmentally, young adults are continuing to accrue and refine cognitive skills and psychological competencies for mature decision making and self-regulation, and they face fewer natural threats to physical health compared with older adults. As a result, they should engage in less risky behavior than adolescents and be in better health than older adults, both of which are true to some extent. Socially, however, they tend to live more outside the purview of their parents relative to adolescents, and they are less governed by their family’s lifestyle and health habits—with less parental monitoring of sleep, curfews, peer relations, physical activity, and diet (Harris et al., 2005). At the same time, compared with older adults, they are less likely to participate in work and family roles that serve as strong social controls on risk taking. And they often have less access to quality health care than younger adolescents or older adults. Consequently, some of the health advantages of young adulthood relative to adolescence or older adulthood may be undermined, and the period of vulnerability often associated with adolescence may be lengthened (Harris et al., 2006; Neinstein, 2013; Schulenberg and Maggs, 2002).
Table 2-1 shows the top 10 causes of death among young adults in the United States. The top five are related in part to lifestyles, behaviors, and risk taking, especially the top three (injury, homicide, and suicide). The same is true of many other causes of death just below the top five, such as HIV. In this way, young adulthood has been described as a transitional period between behavioral causes of death in adolescence and health-related causes of death in later adulthood (Neinstein, 2013).
Looking more closely at the top two causes of death, rates of unintentional injury and homicide are higher among young adults—especially males—than among any other age group (CDC, 2012). Motor vehicle crashes account for the largest percentage of unintentional injuries, and young adults face the highest risk. Compared with those aged 26-34, young adults aged 18-25 are more likely to die or be injured in a motor vehicle crash and have more motor vehicle crash–related hospitalizations and emer-
TABLE 2-1 Leading Causes of Death in the United States (per 100,000 population), Ages 12-34
|Rank||Ages 12-17||Ages 18-25||Ages 26-34|
|Cause of Death||No.||Cause of Death||No.||Cause of Death||No.|
|1||Unintentional Injury||11.9||Unintentional Injury||39.1||Unintentional Injury||27.1|
|4||Malignant Neoplasms||2.7||Malignant Neoplasms||4.4||Malignant Neoplasms||9.0|
|5||Heart Disease||1.1||Heart Disease||3.2||Heart Disease||8.3|
|6||Congenital Anomalies||0.9||Congenital Anomalies||1.1||HIV||2.5|
|7||Cerebrovascular||0.3||Diabetes Mellitus||0.6||Diabetes Mellitus||1.5|
|8||Chronic Lower Respiratory Disease||0.3||HIV||0.6||Cerebrovascular||1.4|
|9||Influenza & Pneumonia||0.3||Influenza & Pneumonia||0.6||Liver Disease||1.1|
|10||Benign Neoplasms||0.2||Cerebrovascular||0.5||Congenital Anomalies||0.9|
SOURCE: Neinstein, 2013, reprinted with permission.
gency room visits (CDC, 2012). Young adults also are at greatest risk of injury due to firearms; young adult males have 10 times the risk of such an injury compared with young adult females (CDC, 2012).
With respect to basic health behaviors, Harris and colleagues (2006) tracked the health and health behavior of adolescents during their transition to young adulthood using National Longitudinal Study of Adolescent Health (Add Health) data. They examined 20 of the leading health indicators recognized in Healthy People 2010—the national public health agenda—as most critical to the development of healthy young people and tracked these indicators for the same cohort of individuals beginning when they were aged 12-18 until they were aged 19-26. Although there were some positives, the dominant pattern was declining health, seen most clearly in health behaviors and related health statuses. As these individuals entered their early and mid-20s, they were less likely to exercise, eat breakfast, and get regular physical checkups and dental checkups, and they were more likely to east fast food, contract sexually transmitted diseases, smoke cigarettes, binge drink, and use marijuana and hard drugs (Harris et al., 2006).
Substance use among young adults warrants special attention. The steady increase in substance use that begins in adolescence peaks during the young adult years (Johnston et al., 2014). Unlike many of the trends discussed in this report, this escalation of substance use tends to be as high or higher among middle-class whites relative to other groups (Johnston et al., 2014). Young adult rates and trajectories of substance use show considerable historical variation, reflecting cohort and period effects over the past 30 years (Johnston et al., 2014). Of particular concern, the rate of increase in use of alcohol and marijuana during this time period has become more rapid for more recent cohorts (Jager et al., 2013). At the same time, the general declines in substance use that characterize the rest of adulthood also tend to start in young adulthood; both sets of changes are associated with social role changes during this period (Bachman et al., 2001; Schulenberg and Maggs, 2002). Alcohol use and especially binge drinking generally peak in the early 20s before declining, a trajectory that is especially pronounced among college students (as discussed in Chapter 4); depending on the historical period, marijuana use tends to peak somewhat earlier (Johnston et al., 2014). Also depending on the historical period, annual and 30-day cigarette use tends to peak in the middle 20s and then decline; daily cigarette use, however, continues to increase with age across the 20s (Johnston et al., 2014). Thus, young adult health behavior is risky in many ways but also suggests a nascent positive trend. Another way of looking at these patterns is that young adulthood may be the last gasp of many of the behavioral risks of the early life course.
Along with these health risk behaviors, young adults also engage in health-promoting behaviors. For example, young adults (aged 18-24) are
more likely than any other age group of adults to meet the recommended guidelines for physical activity (30 percent, compared with 24 percent of those aged 25-44 and 18 percent of those aged 45-54) (see HHS, 2011). In other words, young adulthood is a mix of positives and negatives when it comes to health behavior. Given that young adult health behavior is likely a foundation for lifelong health trajectories, these patterns are one important lens for understanding that young adulthood is a critical developmental period.
Because young adults tend to be in better health than older adults, they are often thought to be in good health, but this is not necessarily true. Evidence suggests that the health status of young adults in the United States varies considerably. For example, overall obesity rates increase through adulthood, rising from 23 percent in those aged 20-24; to 35 percent among those in their late 20s, 30s, and early 40s; and to more than 40 percent at older ages (Harris, 2010). That being said, the rate among young adults is strikingly high (about one-quarter of the age group) and appears to be rising. In Add Health, a longitudinal study, obesity rates more than tripled from 11 percent in adolescence in 1995 to 37 percent by young adulthood in 2008 (Harris, 2010). Research documenting the emergence of the obesity epidemic has found that rising body mass indexes and obesity prevalence first occurred in the 1990s (particularly among adolescents and somewhat among children) (Lee et al., 2010, 2011), so current cohorts of young adults are entering adulthood with much higher obesity rates relative to previous cohorts of young adults and are the first generation to experience dramatically rising obesity rates in childhood and adolescence and they carry this health burden into adulthood. Importantly, the rate of increase in obesity across the age transition has been found to vary by educational experiences and expectations (Clarke et al., 2013).
In terms of obesity-related conditions, more than one in four young adults aged 24-32 in Add Health had hypertension, 69 percent were prehypertensive, 7 percent had diabetes, and 27 percent were prediabetic with impaired glucose tolerance or hyperglycemia (Gooding et al., 2014; Nguyen et al., 2011, 2014). Hypertension and diabetes are known risk factors for stroke, and the data reveal troubling increases in hospitalization for and prevalence of stroke among young adults over the past decade (George et al., 2011; National Center for Health Statistics, 2011). Alarmingly, because many of these conditions (e.g., high blood pressure, hyperglycemia) are asymptomatic and young adults typically are not exposed to routine screening systems or may not see a health care provider regularly, they often are unaware of ongoing and permanent damage caused by chronic conditions.
The levels of these health conditions suggest a higher than previously anticipated risk of cardiovascular disease in an age group often characterized as unburdened by chronic disease (Gordon-Larsen et al., 2004, 2010; Nguyen et al., 2011; Whitsel et al., 2011, 2012). Overall, the current generation of young adults appears to be at the forefront of the obesity epidemic and is vulnerable to experiencing its comorbid consequences.
Mental health among young adults also is cause for concern. Along with substance use, mental health disorders are the greatest source of disability among young adults in the United States. Indeed, nearly two-thirds of the burden of disability in young adults is associated with either mental health or substance use disorders (Davis, 2013), and by age 29, more than half of all individuals have experienced such a disorder (Kessler et al., 2005). The onset of the most serious mental health conditions—psychotic disorders—typically occurs in young adulthood (Seidman, 2013). Likewise, depression increasingly becomes a concern in young adulthood, as do suicidal thoughts, attempts, and deaths (recall the high placement of suicide in Table 2-1). Compared with those aged 25-34, young adults aged 18-25 have higher rates of serious psychological distress, and they are more likely to think about, plan for, and attempt suicide (SAMHSA, 2009). Compared with adolescents, young adults also are more likely to complete suicide (SAMHSA, 2009). Yet only a quarter of young adults with these experiences receive treatment or services, and they are more likely than older adults and adolescents to drop out of or discontinue treatment (SAMHSA, 2009). In many ways, they get lost within a health care system that treats them like adults even though they have special needs relative to other adults (Davis, 2013). That the specific mental health needs of young adults (relative to adolescents or all adults) rarely are studied on their own impedes the ability to serve this population.
In sum, the transition into adulthood is a critical period in health—despite the wide heterogeneity of experiences, health tends to worsen during this period and the higher levels of poor health in young adulthood tend to set the trajectories into adulthood with important consequences for future health (Harris, 2010). During the exploratory years of this transition, young adults as a group continue risk taking and poor (although improving) decision making that expose them to such health risks as unintended injury, unprotected sex, violence, binge drinking, motor vehicle accidents, suicide, and poor diet and nutrition, with potential adult consequences of liver and neurological disease, cardiac impairment, and stroke, as well as mortality (Clark et al., 2001; Johnston et al., 2014). As young adulthood comes to a close, there tend to be general improvements in health behavior.
The majority of young adults’ health problems are preventable. The Affordable Care Act and other recent efforts to increase young adult health care coverage at the state level provide opportunities to enhance preventive
care for young adults. However, efforts to provide them with preventive care are complicated by the lack of preventive guidelines for this age group and the fact that navigating the health care system during the transition from pediatric to adult providers is confusing and difficult, especially for those with behavioral health problems or a chronic disease (see Chapter 7).
Poor health in young adults has numerous negative impacts on individuals and on society at large. Beyond such obvious impacts as health care costs, it adversely affects national security, as reflected in the recruitment of military personnel. For example, estimates indicate that 12 percent of all age-eligible men and 35 percent of all age-eligible women were unable to meet U.S. Army standards for weight-to-height ratio and percent body fat in 2007-2008 (Cawley and Maclean, 2012). Furthermore, the Department of Defense reported that between 2006 and 2011, 62,000 individuals who arrived for military training failed their entrance physical because of their weight (Cutler and Miller, 2013).
The health of young adults varies by race, ethnicity, sex, sexual identity, age, disability, education, socioeconomic position, and geographic location (Hudson et al., 2013; Mulye et al., 2009). Certain populations of young adults have higher rates of such risky behaviors as unhealthy eating, lack of physical activity, unprotected sexual activity, substance use, and unsafe driving. In addition, major gender differences exist, as well as considerable ethnic and racial disparities, with non-Hispanic black and American Indian/non-Hispanic Alaska Native young adults faring worse in many areas (Park et al., 2014). There are also gaps in knowledge about the health of certain groups, such as LGBT young adults and young adults living in poverty (for an overview of similar gaps in adolescent data, see Knopf et al., 2007). At the same time, it is important to note that the differences go both ways. Among young adults, for instance, black males have a higher homicide rate than white males (100.3 versus 11.4 homicides per 100,000) (Smith and Cooper, 2013), but black males have a lower rate of illicit substance use than white males from early adolescence to young adulthood (Chen and Jacobson, 2012).
The United States today is in the midst of “an explosion of diversity” (William Frey, quoted in Ohlemacher, 2006, p. 1). Based on the 2010 census count, one of every three Americans is a person of color (U.S. Census Bureau, 2010). If these demographic patterns continue, non-Hispanic Euro-
pean Americans will cease to be a majority population in the United States before 2050, and there will be no racial or ethnic majority (U.S. Census Bureau, 2012). These dramatic shifts in the “vanguard of America’s new racial and ethnic diversity” are most evident in the booming population of minority youth (Johnson and Lichter, 2012, p. 32) and are likely, over time, to have a profound effect on the attitudes and experiences of adolescents and young adults as they are growing up, forming their group identities, and envisioning their place in the national community. Indeed, changes in the experiences of future cohorts of young adults will provide a useful measure of the extent to which coming of age in an increasingly diverse society affects the development of racial and ethnic identity, intergroup relations, and evolving conceptions of national identity.
In the meantime, however, many people of color continue to encounter systematic prejudice and discrimination that restrict opportunity and reduce well-being in pervasive ways and that contribute to the disparities in health and well-being of young adults documented throughout this report. Further, resistance to immigration in some parts of the country has heightened concerns about bias and discrimination based on ethnicity and religion (Cauce et al., 2011; Kim et al., 2013). Effects of bias and discrimination on health and well-being, as well as factors that protect or buffer young people against these effects, are briefly summarized here, considered throughout the report, and explored in greater depth in Appendix B.
The experience of being exposed to biased and discriminatory behavior has been characterized as a pervasive and normative stressor in the lives of people of color (García Coll et al., 1996). A 2013 national survey of adults by the Pew Research Center (2013a,b) indicates that 88 percent of non-Hispanic blacks and 57 percent of non-Hispanic whites believe that blacks are subject to “some”/“a lot” of discrimination in the United States. Among all adults, 73 percent say that Muslim Americans are subject to “some”/“a lot” of discrimination, while 65 percent hold this view of Hispanics.
Experiencing bias and discrimination has been linked to poorer outcomes in education and employment, worse physical and psychological outcomes, and acculturation stress. For example, African Americans and Hispanics are overrepresented among high school dropouts, and the associations between early school leaving and young adults’ future outcomes, including joblessness, have been well established (see Chapter 4 of this report). Among the many interrelated family, social, and economic factors that contribute to educational disadvantage for minorities, it is widely acknowledged that the differential treatment of minority children in school classification and discipline policies plays a significant role (Alfaro et al., 2009; NRC, 2013; U.S. Department of Education and National Center for Education Statistics, 2014). Several systematic reviews (Lee et al., 2009; Priest et al., 2013; Williams and Williams-Morris, 2000; Williams et al.,
2003) have found strong associations between racial discrimination and mental health outcomes among all racial/ethnic groups. A recent meta-analytic review of experimental and correlational studies concludes that perceiving pervasive instances of discrimination negatively affects psychological well-being across a wide range of measures (Schmitt et al., 2014). Persistent exposure to race-related stress increases “allostatic load,” and the accompanying heightened physiological responses are significant predictors of chronic diseases (Karlamangla et al., 2006).
Current patterns of discrimination are associated with structural factors (e.g., economic and/or residential segregation, institutional racism) that restrict opportunity and affect well-being in pervasive ways. However, it is also important to recognize that disadvantaged cultural groups have developed productive, adaptive means of coping with their deprivations and that individual resilience and family strengths play important roles in supporting the healthy development of ethnic minority young adults even in the face of societal stressors (García Coll et al., 1996). Several studies have identified factors that buffer, protect against, or reduce the impact of racism and discriminatory experiences on individuals (Luthar, 2006). These factors include social support, connections, feelings of belonging, and cultural socialization. For more detailed discussion, see Appendix B.
The committee’s key findings and their implications for the health, safety, and well-being of young adults are summarized below and discussed in greater detail in subsequent chapters of this report. Attention to these findings is intended to achieve progress toward ensuring the following key outcomes for young adults, with a particular focus on those young adults who are economically disadvantaged or otherwise marginalized:
- housing stability,
- healthy relationships and connections to responsible adults,
- civic engagement and community involvement, and
- effective parenting.
1. Young adulthood is a critical developmental period.
Like childhood and adolescence, young adulthood is a developmentally distinct period of the life course that can sensibly be viewed as a critical
window of development with a strong effect on long-term trajectories. It is a time when individuals face significant challenges and are expected to assume new responsibilities and obligations. Success or failure in navigating these paths can set young adults on a course that will strongly affect the future trajectories of their adult lives. Early developmental and social trajectories may be reinforced or reversed, early risks may accumulate or be counteracted, new experiences can be turning points or sources of stagnation or thriving, and developmental tasks not completed may constitute a significant setback for the future.
Developmentally, young adulthood is a time of both opportunity and risk. The process of maturation is not suddenly completed when a young person turns 18. The brain is still maturing, and strengths and vulnerabilities continue to emerge. Thus, young adults continue to be strongly responsive to education and training and to incentives to create and contribute. Mistakes and failures can be reversed, and timely preventive interventions can reduce risks and ameliorate the consequences of injuries or disorders.
2. The world has changed in ways that place greater demands on young adults.
Although the normal course of physiological and biological development of young adults probably has not changed in generations, the world in which they live has changed greatly. Today’s young adults live in a more global and networked world, marked by increased knowledge and information transfer, heightened risks, fairly low social mobility, and greater inequality. Economic restructuring, advances in information and communication technologies, and changes in the labor market have radically altered the landscape of risk and opportunity in young adulthood. Demands are higher, and there is less latitude for failure. Much of the burden of a restructured economy has been borne by the current cohort of America’s young adults. Developmentally speaking, young people are resilient and adaptable, but many young adults are struggling to find a path to employment, economic security, and well-being.
3. Young adults today follow less predictable pathways compared with young adults in previous generations.
Beginning in the 1970s, several well-established patterns of social and economic transition that once defined young adulthood have been altered. In previous generations, the path for most young adults was predictable: graduate from high school, enter college or the workforce, leave home, find a spouse, and start a family (Fussell, 2002). While there were always exceptions, these established milestones provided structure and direction for
young adults as they assumed adult responsibilities. Today, those pathways are considerably less predictable, often extended, and sometimes significantly more challenging, as the following examples illustrate:
- The cost of college has grown substantially, and many students have difficulty financing the investment or repaying the debt, yet prospects for well-paying jobs for high school graduates without some postsecondary credential are slim. Although many young adults enter college, dropout rates are high, and the number of years needed to finish degree programs has risen.
- Well-compensated entry-level jobs are becoming more difficult to find, even for young college graduates, and especially in the aftermath of the Great Recession. Many companies do not provide health insurance or other nonsalary economic benefits. Low earnings plague many young workers because they lack skills needed for higher-paying knowledge-based jobs, increasing numbers of the jobs available to them are part time, and institutions that have traditionally protected less-educated workers have been weakened.
- The estimate of a recent study is that 6.7 million youth and young adults aged 16-24—about 17 percent of the population in this age range—are neither in school nor working (Belfield and Levin, 2012). The rates are highest among African Americans and those aged 20-24, almost all of whom have left high school.
- Partnership and parenting patterns have shifted substantially. Many educated young adults live together for many years before marrying and having children, while many less-educated young adults have children outside of marriage before gaining the skills and income to support them. In addition, rapidly changing laws on same-sex marriage are providing new opportunities for family formation among LGBT young adults.
- The high cost of living independently has encouraged many young adults to move back into their parents’ home, a pattern well documented among the “millennial” generation.2
4. Inequality can be magnified during the young adult years.
The disruption of established social and economic pathways has presented more choices and opportunities for some young adults while creating more barriers for others. The young adult population has diverse strengths, needs, social supports, and financial resources. Many young adults quickly
2 A variety of age ranges are used to define the millennial generation. One example is those born between 1982 and 2003.
assume typical adult roles, although perhaps tenuously and continuing to need institutional support. Others reach the end of this period without assuming any adult roles and having few prospects, suggesting a lack of opportunities, experiences, skills, and/or maturity. These divergent trajectories reflect not only differences in psychological, social, and physical capacities but also differential opportunities rooted in economic and social inequality. Persistent prejudice and discrimination limit opportunities and mobility for racial, ethnic, and religious minorities, as well as individuals with disabilities and divergent sexual preferences, and can also have an adverse impact on health (see Appendix B).
In addition, marginalized young adults—such as those aging out of foster care, those in the justice system, those with disabilities, young parents, and children of low-income immigrants—are much less likely than other young adults to experience a successful transition to adulthood, although some of these young people ultimately fare very well as adults, and their hopes and aspirations are similar to those of their peers who have not been marginalized. Meeting the needs of marginalized groups not only improves their lives but also has the potential to help them become fully contributing members of society. In the absence of deliberate remedial action, however, this period of development is likely to magnify inequality, with lasting effects throughout adulthood.
5. Young adults connect generations.
As the children of prior generations and the parents of future generations, young adults are deeply embedded in family systems both at the level of individual families and at the population level. As a result, young adult experiences are shaped by the advantages and disadvantages their parents bring to their lives, and these experiences become the contexts for the parenting of their own children. The simultaneous proximity of young adults to being dependent children of parents and parents of dependent children creates both risks and opportunities.
6. Young adults are at the forefront of social change.
U.S. history is a story of sweeping economic, demographic, social, and technological changes, and young adults have long been at the leading edge of these changes. People in this age group tend to be highly interested in the broader world, their place in it, and how they can and do make a difference. They are greatly affected by global economic change, tend to be less conflicted than older adults about divisive cultural debates concerning behavioral norms and values, and are early adopters of new technologies—digital and social media being the most salient current example. They also
are the leading edge of “an explosion of diversity” (William Frey, quoted in Ohlemacher, 2006, p. 1) that will change the face of the nation, which, if current demographic trends continue, will have no racial or ethnic majority by 2050. As a result, adults who conduct research and design policies in any one era cannot simply extrapolate their own young adult experiences to those of the current cohort of young adults.
7. Young adults are surprisingly unhealthy.
Young adulthood is a critical period for protecting health, not just during the transitional years but over the life course. Despite some positives, however, the dominant pattern among young adults today is declining health, seen most clearly in health behaviors and related health statuses such as the following:
- As adolescents age into their early and mid-20s, they are less likely to eat breakfast, exercise, and get regular physical and dental checkups, and more likely to eat fast food, contract sexually transmitted diseases, smoke cigarettes, use marijuana and hard drugs, and binge drink.
- In many areas of risky behavior, young adults show a worse health profile than both adolescents and older adults. Thus, young adulthood is when many risky behaviors peak, but it is also the time when involvement in risky behaviors begins to decline. Across this time period are many opportunities for prevention and early intervention.
- Early adulthood is a time of heightened psychological vulnerability and onset of serious mental health disorders, a problem compounded by failure to recognize illness or to seek treatment.
- The current generation of young adults appears to be at the forefront of the obesity epidemic and is more vulnerable than previous generations to obesity-related health consequences in later years.
The higher levels of poor health in young adulthood have important consequences for future health, educational attainment, and economic well-being. Rapid technological changes, economic challenges, and a prolonged transition to adulthood appear to be contributing to the health problems of young adults by increasing their stress and sedentary habits while making them less likely to participate in work and family roles that serve as strong social controls on risk taking. Therefore, these worrisome trends in young adult health can be expected to continue or worsen.
Young adults are different from both adolescents and older adults, yet they often are combined with one or the other in statistical reporting and research design, as well as in policy and program classification. As a result, not enough is known about the special strengths and vulnerabilities of this population, as well as the ways in which socioeconomic and demographic disparities during this period of the life course contribute to disparities in the population at large. Likewise, little is known about the relative importance of young adulthood and other periods of the life course for long-term health and well-being. Furthermore, because of historical changes in how young adults live and what is expected of them, one cannot easily extrapolate from past research or policy traditions to today. An active, productive, and resilient population of young adults will benefit not only these young people but all members of U.S. society and the nation as a whole. Using the above findings and implications as a foundation, we offer corresponding principles to guide action that will help achieve this goal and that structure the discussion in the chapters to follow. Subsequent chapters provide an in-depth discussion of policies and programs in key domains for young adults’ health and well-being, along with specific recommendations for key actors.
Principle 1: Pay specific attention to young adults in research and policy.
Given the critical nature of young adulthood within the life course, it needs to be studied on its own rather than as an extension of adolescence or as a fungible period of adulthood. At the same time, long-term studies that embed this period within the life course are needed to elucidate both the independent and interconnected roles of young adult experiences in long-term life-course outcomes. Young adults often are cut off from child/adolescent services they may still need and are treated the same as older adults in adult services. Policy makers should ensure that outcomes are measured specifically for young adults and that programs take account of relevant differences between young and older adults.
Principle 2: Create economic opportunities for young adults.
A shrinking number of well-paying jobs for young adults without a college education, the cost of higher education, and the prolonged period of transition to adult roles, exacerbated by economic volatility, pose an underlying threat to young adults’ healthy adjustment and functioning. Taking action to improve prospects for social mobility can address the fundamental risks these young people face in modern society, risks that themselves have implications for the overall stability and progress of the nation.
Principle 3: Allow flexibility in policies and programs for young adults.
Given the absence of clear normative pathways during this period of the life course, the transitions and subsequent trajectories of young adults depend on both the individual characteristics of young adults and the environments in which they are embedded. Thus, efforts to serve this population through policies and programs need to be tailored to the various subpopulations of young adults, defined not just developmentally but also demographically and socioeconomically. Age alone during this period of life should not necessarily define needs and dictate programming. Flexibility is needed in defining eligibility criteria and program requirements.
Principle 4: Invest in the least advantaged young adults.
The prolonged period of educational attainment, together with its increasing costs, poses substantial burdens for the vast majority of families. But these challenges are especially daunting for the least advantaged families and the most marginalized young adults. Both research and policy should focus not just on increasing absolute levels of health, educational attainment, or other desired outcomes for young adults as a group, but also on making the investments needed to increase the productivity, health, and well-being of the many who are being left behind, as well as rectifying persistent racial and ethnic disparities.
Principle 5: Use multigenerational strategies to support young adults and their children.
Multigenerational investments and interventions are a promising trend in policy and practice that needs to receive greater attention. Supporting the human capital and workforce development of young parents is likely an investment in the long-term developmental trajectories of their children, and programs focused on the early health and education of young children provide an opportunity to reach their parents, many of whom are young adults. Targeting the connections between generations, therefore, offers two ways to serve young adults, with ripple effects over time.
Principle 6: Empower and engage young adults in policies and programs.
Young adults need to be at the table when decisions that affect them are being made, both because they deserve to be involved and because their input will contribute to better decision making. Their interest in such involvement is likely to be strong given their expanding perspective on the world. The influence of social media on young adult development and
functioning is not yet fully understood, and the potential for social media to facilitate the implementation of policies and programs, especially in public health and health care, has not been fully tapped. Both research and policy agendas need to integrate social media and related information technologies. Because young adults typically are more expert in social media than many researchers and policy makers, the incorporation of social media into these agendas would be an example of the broader value of giving young adults a voice in the process.
Principle 7: Invest in preventive approaches to improve the health of young adults.
Traditionally, the nation’s health system has underemphasized preventive health services for young adults. Young adults’ lack of health care insurance coverage often precludes them from seeking health care services, including the provision of preventive screening and services, although this gap has been somewhat alleviated by the Affordable Care Act and Medicaid expansion in some states. The role of families in ensuring continuity with a health care provider that offers preventive services also is diluted as young adults age out of their pediatrician’s practice. Yet many of the risk behaviors in which young adults engage can be addressed by population-based interventions, as well as earlier screening and referrals, for example, for clinical and behavioral interventions. The Affordable Care Act, as one example, incorporates preventive health services as part of health insurance coverage. Given the act’s emphasis on preventive services in such areas as reproductive health, substance abuse, and mental health, which reflect many of the health care needs of young adults, those young adults who enroll can clearly benefit from this newly available care.
The stability and progress of society at large depend on how any cohort of young adults fares as a whole. The same can be said of each cohort of children and adolescents, of course, but it is the transition to adulthood that reflects the end of trial periods and the beginning of more consequential actions. Young adults’ successful transition to independent and healthy adulthood, entry into the workforce, continued productivity, and successful parenting can help ensure the security and well-being of the nation. A healthy and productive generation of young adults nurtures the next generation and provides the worker replacement needed to support the retiring generation.
Focusing on the health and well-being of the current cohort of young adults (those becoming adults in the first third of the 21st century) is es-
pecially important because of the powerful (and perhaps transformative) economic and social forces now at work. One is the rapidly increasing “elder dependency ratio” (i.e., the ratio of individuals in the population aged 65 and older to the working-age population). This ratio has been increasing rapidly in all advanced industrial countries while the fertility rate has been declining, leaving the current cohort of working-age adults to support increasing numbers of retiring elders. In the United States, the elder dependency ratio increased from about 1 elder to 10 workers (0.1) in 1950 to 0.2 in 2000 and is expected to increase to 0.35 by 2050 (Fussell, 2002). This demographic shift led Elizabeth Fussell to call for renegotiating the “intergenerational contract” to couple building human capital through collective investments in young adults with increasing the age of eligibility for retirement support (Fussell, 2002). A similar collective renegotiation may already be occurring, explicitly or implicitly, when parents invest in education and support for young adults well into their 20s.
Another transformative social and economic change now under way is the substantial increase in immigration to the United States. This trend has helped replenish the workforce and attenuate the rise in the elder dependency ratio (which is expected to increase, on average, to about 0.45 in other developed countries by 2050) while also changing the very face of U.S. society (Fussell, 2002). This dramatic change is likely, over time, to have a profound effect on attitudes and experiences of adolescents and young adults as they are growing up, forming group identities, and envisioning their place in the national community. Indeed, changes in the experiences of future cohorts of young adults will provide a useful measure of the extent to which coming of age in an increasingly diverse society affects intergroup relations and evolving conceptions of national identity.
In sum, healthy, productive, and skilled young adults are critical for the nation’s workforce, global competitiveness, public safety, and national security. Providing more of the educational, economic, social, and health supports needed by all young adults—particularly those whose background and characteristics put them at risk of experiencing the greatest struggles—will ensure equal opportunity, erase disparities, and enable more young adults to successfully embrace adult roles as healthy workers, parents, and citizens.
Alfaro, E. C., A. J. Umaña-Taylor, M. A. Gonzales-Backen, M. Y. Bámaca, and K. H. Zeiders. 2009. Latino adolescents’ academic success: The role of discrimination, academic motivation, and gender. Journal of Adolescence 32(4):941-962.
Arnett, J. J. 2004. Emerging adulthood: The winding road from the late teens through the twenties. New York: Oxford University Press.
Arroyo, J., K. K. Payne, S. L. Brown, and W. D. Manning. 2013. Crossover in median age at first marriage and first birth: Thirty years of change. Bowling Green, OH: National Center for Family and Marriage Research.
Bachman, J. G., P. M. O’Malley, J. E. Schulenberg, L. D. Johnston, A. L. Bryant, and A. C. Merline. 2001. The decline of substance use in young adulthood: Changes in social activities, roles, and beliefs. New York: Psychology Press.
Bailey, M. J., and S. M. Dynarski. 2011. Gains and gaps: Changing inequality in U.S. college entry and completion. Cambridge, MA: National Bureau of Economic Research.
Baum, S., and S. Flores. 2011. Higher education and children in immigrant families. The Future of Children 21:171-193.
Belfield, C., and H. Levin. 2012. The economics of investing in opportunity youth. New York: Civic Enterprises.
Bernhardt, A., M. Morris, M. S. Handcock, and M. A. Scott. 2001. Divergent paths: Economic mobility in the new American labor market. New York: Russell Sage Foundation.
Blakemore, S.-J. 2008. The social brain in adolescence. Nature Reviews Neuroscience 9(4): 267-277.
Bound, J., M. F. Lovenheim, and S. Turner. 2010. Why have college completion rates declined? An analysis of changing student preparation and collegiate resources. American Economic Journal-Applied Economics 2(3):129-157.
Brock, T. 2010. Young adults and higher education: Barriers and breakthroughs to success. The Future of Children 20(1):109-132.
Cauce, A. M., R. Cruz, M. Corona, and R. Conger. 2011. The face of the future: Risk and resilience in minority youth. In Health disparities in youth and families. New York: Springer. Pp. 13-32.
Cauffman, E., E. P. Shulman, L. Steinberg, E. Claus, M. T. Banich, S. Graham, and J. Woolard. 2010. Age differences in affective decision making as indexed by performance on the Iowa gambling task. Developmental Psychology 46(1):193-207.
Cawley, J., and J. C. Maclean. 2012. Unfit for service: The implications of rising obesity for U.S. military recruitment. Health Economics 21(11):1348-1366.
CDC (Centers for Disease Control and Prevention). 2012. Nonfatal injury report, 2001-2012. http://webappa.cdc.gov/sasweb/ncipc/nfirates2001.html (accessed July 22, 2014).
Chan-Olmsted, S., H. Rim, and A. Zerba. 2013. Mobile news adoption among young adults: Examining the roles of perceptions, news consumption, and media usage. Journalism & Mass Communication Quarterly 90:126-147.
Chein, J., D. Albert, L. O’Brien, K. Uckert, and L. Steinberg. 2011. Peers increase adolescent risk taking by enhancing activity in the brain’s reward circuitry. Developmental Science 14(2):F1-F10.
Chen, P., and K. C. Jacobson. 2012. Developmental trajectories of substance use from early adolescence to young adulthood: Gender and racial/ethnic differences. Journal of Adolescent Health 50(2):154-163.
Cherlin, A. J. 2009. The marriage-go-round. New York: Random House LLC.
Clark, D. B., K. G. Lynch, J. E. Donovan, and G. D. Block. 2001. Health problems in adolescents with alcohol use disorders: Self-report, liver injury, and physical examination findings and correlates. Alcoholism-Clinical and Experimental Research 25(9):1350-1359.
Clark, L. S. 2012. The parent app: Understanding families in the digital age. New York: Oxford University Press.
Clarke, P. J., P. M. O’Malley, J. E. Schulenberg, H. Lee, N. Colabianchi, and L. D. Johnston. 2013. College expectations in high school mitigate weight gain over early adulthood: Findings from a national study of American youth. Obesity 21(7):1321-1327.
Cole, T. J. 2003. The secular trend in human physical growth: A biological view. Economics & Human Biology 1(2):161-168.
Cools, R. 2008. Role of dopamine in the motivational and cognitive control of behavior. The Neuroscientist 14(4):381-395.
Coontz, S. 2000. Historical perspectives on family studies. Journal of Marriage and Family 62(2):283-297.
Crosnoe, R., and M. K. Johnson. 2011. Research on adolescence in the twenty-first century. Annual Review of Sociology 37:439-460.
Cunningham, M. G., S. Bhattacharyya, and F. M. Benes. 2002. Amygdalo-cortical sprouting continues into early adulthood: Implications for the development of normal and abnormal function during adolescence. Journal of Comparative Neurology 453(2):116-130.
Cutler, T., and G. A. Miller. 2013. Retired military generals: Recruits dismissed for obesity cost $1.1 billion a year. http://www.mlive.com/news/index.ssf/2013/09/retired_military_generals_recr.html (accessed August 21, 2014).
Davis, M. 2013. Young adult mental health. Presentation at IOM/NRC Workshop on Improving the Health, Safety, and Well-Being of Young Adults, Washington, DC. http://www.iom.edu/~/media/Files/Activity%20Files/Children/ImprovingYoungAdultsHealth/Davis%20Presentation.pdf (accessed October 10, 2014).
Dennett, J., and A. S. Modestino. 2013. Uncertain futures? Youth attachment to the labor market in the United States and New England. Boston, MA: New England Public Policy Center.
Dorn, L. D., R. E. Dahl, H. R. Woodward, and F. Biro. 2006. Defining the boundaries of early adolescence: A user’s guide to assessing pubertal status and pubertal timing in research with adolescents. Applied Developmental Science 10(1):30-56.
Edin, K., and M. Kefalas. 2005. Promises I can keep: Why poor women put motherhood before marriage. Oakland: University of California Press.
Ernst, M., D. S. Pine, and M. Hardin. 2006. Triadic model of the neurobiology of motivated behavior in adolescence. Psychological Medicine 36(3):299-312.
Fingerman, K. L., Y. P. Cheng, E. D. Wesselmann, S. Zarit, F. Furstenberg, and K. S. Birditt. 2012. Helicopter parents and landing pad kids: Intense parental support of grown children. Journal of Marriage and Family 74(4):880-896.
Fischer, C. S., and M. Hout. 2006. Century of difference: How America changed in the last one hundred years. New York: Russell Sage Foundation.
Frick, W. 2014. How old are Silicon Valley’s top founders? Here’s the data. Harvard Business Review, April 3.
Fry, R. 2013. A rising share of young adults live in their parents’ home. Philadelphia, PA: Pew Research Center.
Furstenberg, Jr., F. F. 2010. On a new schedule: Transitions to adulthood and family change. The Future of Children 20(1):67-87.
Fussell, E. 2002. Youth in aging societies. In The future of adolescent experience: Societal trends and the transition to adulthood, edited by J. Mortimer and R. Larson. New York: Cambridge University Press. Pp. 18-51.
Fussell, E., and F. Furstenberg. 2005. The transition to adulthood during the 20th century: Race, nativity and gender. In On the frontier of adulthood: Theory, research, and public policy, edited by R. Settersten, F. Frustenberg, and R. Rumbaut. Chicago, IL: University of Chicago Press. Pp. 29-75.
Fuster, J. M. 2002. Frontal lobe and cognitive development. Journal of Neurocytology 31(3-5):373-385.
Fuster, J. M. 2008. The prefrontal cortex. 4th ed. Oxford, UK: Elsevier Ltd.
Galván, A., T. A. Hare, C. E. Parra, J. Penn, H. Voss, G. Glover, and B. Casey. 2006. Earlier development of the accumbens relative to orbitofrontal cortex might underlie risk-taking behavior in adolescents. The Journal of Neuroscience 26(25):6885-6892.
García Coll, C., G. Lamberty, R. Jenkins, H. P. McAdoo, K. Crnic, B. H. Wasik, and H. Vázquez García. 1996. An integrative model for the study of developmental competencies in minority children. Child Development 67(5):1891-1914.
Gee, D. G., K. L. Humphreys, J. Flannery, B. Goff, E. H. Telzer, M. Shapiro, T. A. Hare, S. Y. Bookheimer, and N. Tottenham. 2013. A developmental shift from positive to negative connectivity in human amygdala-prefrontal circuitry. Journal of Neuroscience 33(10):4584-4593.
Geier, C., R. Terwilliger, T. Teslovich, K. Velanova, and B. Luna. 2010. Immaturities in reward processing and its influence on inhibitory control in adolescence. Cerebral Cortex 20(7):1613-1629.
George, M. G., X. Tong, E. V. Kuklina, and D. R. Labarthe. 2011. Trends in stroke hospitalizations and associated risk factors among children and young adults, 1995-2008. Annals of Neurology 70(5):713-721.
Giedd, J. N., F. X. Castellanos, J. C. Rajapakse, A. C. Vaituzis, and J. L. Rapoport. 1997. Sexual dimorphism of the developing human brain. Progress in Neuro-Psychopharmacology and Biological Psychiatry 21(8):1185-1201.
Gogtay, N., J. N. Giedd, L. Lusk, K. M. Hayashi, D. Greenstein, A. C. Vaituzis, T. F. Nugent, D. H. Herman, L. S. Clasen, and A. W. Toga. 2004. Dynamic mapping of human cortical development during childhood through early adulthood. Proceedings of the National Academy of Sciences of the United States of America 101(21):8174-8179.
Goldin, C. D., and L. F. Katz. 2008. The race between education and technology. Cambridge, MA: Belknap Press of Harvard University Press.
Gooding, H.C., S. McGinty, T. K. Richmond, M. W. Gillman, and A. E. Field. 2014. Hypertension awareness and control among young adults in the National Longitudinal Study of Adolescent Health. Journal of General Internal Medicine 29(8):1098-1104.
Gordon-Larsen, P., L. S. Adair, M. C. Nelson, and B. M. Popkin. 2004. Five-year obesity incidence in the transition period between adolescence and adulthood: The National Longitudinal Study of Adolescent Health. American Journal of Clinical Nutrition 80(3):569-575.
Gordon-Larsen, P., N. S. The, and L. S. Adair. 2010. Longitudinal trends in obesity in the United States from adolescence to the third decade of life. Obesity (Silver Spring) 18(9):1801-1804.
Greimel, E., B. Nehrkorn, M. Schulte-Rüther, G. R. Fink, T. Nickl-Jockschat, B. Herpertz-Dahlmann, K. Konrad, and S. B. Eickhoff. 2013. Changes in grey matter development in autism spectrum disorder. Brain Structure and Function 218(4):929-942.
Hare, T. A., N. Tottenham, A. Galván, H. U. Voss, G. H. Glover, and B. J. Casey. 2008. Biological substrates of emotional reactivity and regulation in adolescence during an emotional go-nogo task. Biological Psychiatry 63(10):927-34.
Harris, K. M. 2010. An integrative approach to health. Demography 47(1):1-22.
Harris, K. M., R. B. King, and P. Gordon-Larsen. 2005. Healthy habits among adolescents: Sleep, exercise, diet, and body image. In What do children need to flourish? New York: Springer. Pp. 111-132.
Harris, K. M., P. Gordon-Larsen, K. Chantala, and J. R. Udry. 2006. Longitudinal trends in race/ethnic disparities in leading health indicators from adolescence to young adulthood. Archives of Pediatrics & Adolescent Medicine 160(1):74-81.
HHS (U.S. Department of Health and Human Services). 2011. Healthy people 2020. http://www.healthypeople.gov/2020/default.aspx (accessed July 22, 2014).
Holzer, H. J., and E. Dunlop. 2013. Just the facts, ma’am: Postsecondary education and labor market outcomes in the US. Bonn, Germany: IZA (Institute for the Study of Labor).
Hudson, D. L., E. Puterman, K. Bibbins-Domingo, K. A. Matthews, and N. E. Adler. 2013. Race, life course socioeconomic position, racial discrimination, depressive symptoms and self-rated health. Social Science & Medicine 97:7-14.
Hunter, N. D. 2012. Introduction: The future impact of same-sex marriage: More questions than answers. Georgetown Law Journal 100(6):1855-1879.
Jager, J., J. E. Schulenberg, P. M. O’Malley, and J. G. Bachman. 2013. Historical variation in drug use trajectories across the transition to adulthood: The trend toward lower intercepts and steeper, ascending slopes. Development and Psychopathology 25(2):527-543.
Johnson, K. M., and D. T. Lichter. 2012. Rural natural increase in the new century: America’s third demographic transition. In International handbook of rural demography, edited by L. J. Kulcsár and K. J. Curtis. The Netherlands: Springer. Pp. 17-34.
Johnson, M. K., R. Crosnoe, and G. H. Elder. 2011. Insights on adolescence from a life course perspective. Journal of Research on Adolescence 21(1):273-280.
Johnston, L. D., P. M. O’Malley, J. G. Bachman, J. E. Schulenberg, and R. A. Miech. 2014. Monitoring the future national survey results on drug use, 1975-2013. Volume II: College students and adults ages 19-50. Ann Arbor: Institute for Social Research, University of Michigan.
Karlamangla, A. S., B. H. Singer, and T. E. Seeman. 2006. Reduction in allostatic load in older adults is associated with lower all-cause mortality risk: MacArthur studies of successful aging. Psychosomatic Medicine 68(3):500-507.
Kessler, R. C., W. T. Chiu, O. Demler, and E. E. Walters. 2005. Prevalence, severity, and comorbidity of 12-month DSM-IV disorders in the national comorbidity survey replication. Archives of General Psychiatry 62(6):617-627.
Kim, S. Y., Q. Chen, Y. Wang, Y. Shen, and D. Orozco-Lapray. 2013. Longitudinal linkages among parent-child acculturation discrepancy, parenting, parent-child sense of alienation, and adolescent adjustment in Chinese immigrant families. Developmental Psychology 49(5):900-912.
Knopf, D. K., M. J. Park, C. D. Brindis, T. P. Mulye, and C. E. Irwin, Jr. 2007. What gets measured gets done: Assessing data availability for adolescent populations. Maternal and Child Health Journal 11(4):335-345.
Kreager, D. A., S. E. Cavanagh, J. Yen, and M. Yu. 2014. Where have all the good men gone? Gendered interactions in online dating. Journal of Marriage and Family 76(2):387-410.
Lebel, C., L. Walker, A. Leemans, L. Phillips, and C. Beaulieu. 2008. Microstructural maturation of the human brain from childhood to adulthood. NeuroImage 40(3):1044-1055.
Lee, H., D. Lee, G. Guo, and K. M. Harris. 2011. Trends in body mass index in adolescence and young adulthood in the United States: 1959-2002. Journal of Adolescent Health 49(6):601-608.
Lee, J. M., S. Pilli, A. Gebremariam, C. C. Keirns, M. M. Davis, S. Vijan, G. L. Freed, W. H. Herman, and J. G. Gurney. 2010. Getting heavier, younger: Trajectories of obesity over the life course. International Journal of Obesity 34(4):614-623.
Lee, S., H. S. Juon, G. Martinez, C. E. Hsu, E. S. Robinson, J. Bawa, and G. X. Ma. 2009. Model minority at risk: Expressed needs of mental health by Asian American young adults. Journal of Community Health 34(2):144-152.
Lenhart, A. 2013. Young adults, mobile phones and social media: Technology and the transition to adulthood. Presentation at IOM/NRC Workshop on Improving the Health, Safety, and Well-Being of Young Adults, Washington, DC. http://www.iom.edu/~/media/Files/Activity%20Files/Children/ImprovingYoungAdultsHealth/Lenhart%20Presentation.pdf (accessed October 10, 2014).
Lenroot, R. K., N. Gogtay, D. K. Greenstein, E. M. Wells, G. L. Wallace, L. S. Clasen, J. D. Blumenthal, J. Lerch, A. P. Zijdenbos, and A. C. Evans. 2007. Sexual dimorphism of brain developmental trajectories during childhood and adolescence. NeuroImage 36(4):1065-1073.
Lichter, D. T., D. K. McLaughlin, and D. C. Ribar. 2002. Economic restructuring and the retreat from marriage. Social Science Research 31(2):230-256.
Luna, B. 2009. Developmental changes in cognitive control through adolescence. Advances in Child Development and Behavior 37:233-278.
Luna, B., A. Padmanabhan, and K. O’Hearn. 2010. What has fMRI told us about the development of cognitive control through adolescence? Brain and Cognition 72(1):101-113.
Luthar, S. S. 2006. Resilience in development: A synthesis of research across five decades. In Developmental psychopathology, Vol. 3, 2nd ed., edited by D. Cicchetti and D. J. Cohen. Hoboken, NJ: Wiley. Pp. 739-795.
McLanahan, S. 2004. Diverging destinies: How children are faring under the second demographic transition. Demography 41(4):607-627.
Modell, J., F. F. Furstenberg, and T. Hershberg. 1976. Social-change and transitions to adulthood in historical-perspective. Journal of Family History 1(1):7-32.
Mulye, T. P., M. J. Park, C. D. Nelson, S. H. Adams, C. E. Irwin, Jr., and C. D. Brindis. 2009. Trends in adolescent and young adult health in the United States. Journal of Adolescent Health 45(1):8-24.
National Center for Health Statistics. 2011. Health, United States, 2011. Washington, DC: U.S. Government Printing Office.
Neinstein, L. 2013. The new adolescents: An analysis of health conditions, behaviors, risks and access to services among young adults. Los Angeles: University of Southern California.
Nguyen, Q. C., J. W. Tabor, P. P. Entzel, Y. Lau, C. Suchindran, J. M. Hussey, C. T. Halpern, K. M. Harris, and E. A. Whitsel. 2011. Discordance in national estimates of hypertension among young adults. Epidemiology 22(4):532-541.
Nguyen, Q. C., E. A. Whitsel, J. W. Tabor, C. C. Cuthbertson, M. H. Wener, A. J. Potter, C. T. Halpern, L. A. Killeya-Jones, J. M. Hussey, C. Suchindran, and K. M. Harris. 2014. Blood spot-based measures of glucose homeostasis and diabetes prevalence in a nationally representative population of young U.S. adults. Annals of Epidemiology (published online ahead of print). http://dx.doi.org/10.1016/j.annepidem.2014.09.010 (accessed October 22, 2014).
NRC (National Research Council). 2013. Reforming juvenile justice: A developmental approach. Washington, DC: The National Academies Press.
Ohlemacher, S. 2006. Diversity grows in 49 of 50 states. Associated Press. http://seattletimes.com/html/nationworld/2003199276_diversity15.html (accessed October 16, 2014).
Ordaz, S., and B. Luna. 2012. Sex differences in physiological reactivity to acute psychosocial stress in adolescence. Psychoneuroendocrinology 37(8):1135-1157.
Ordaz, S. J., W. Foran, K. Velanova, and B. Luna. 2013. Longitudinal growth curves of brain function underlying inhibitory control through adolescence. Journal of Neuroscience 33(46):18109-18124.
Padmanabhan, A., and B. Luna. 2013. Developmental imaging genetics: Linking dopamine function to adolescent behavior. Brain and Cognition 89(0):27-38.
Park, M. J., J. T. Scott, S. H. Adams, C. D. Brindis, and C. E. Irwin, Jr. 2014. Adolescent and young adult health in the United States in the past decade: Little improvement and young adults remain worse off than adolescents. Journal of Adolescent Health 55(1):3-16.
Parke, R. D. 2013. Future families: Diverse forms, rich possibilities. Hoboken, NJ: John Wiley & Sons.
Patrick, M. E., J. E. Schulenberg, and P. M. O’Malley. 2013. High school substance use as a predictor of college attendance, completion, and dropout: A national multicohort longitudinal study. Youth & Society 1-23.
Payne, K. 2011. FP-11-11. On the road to adulthood: Sequencing of family experiences. http://scholarworks.bgsu.edu/ncfmr_family_profiles/10 (accessed July 22, 2014).
Payne, K. 2012. FP-12-04. School enrollment and completion. http://scholarworks.bgsu.edu/ncfmr_family_profiles/17 (accessed July 22, 2014).
Petanjek, Z., M. Judaš, G. Šimić, M. R. Rašin, H. B. Uylings, P. Rakic, and I. Kostović. 2011. Extraordinary neoteny of synaptic spines in the human prefrontal cortex. Proceedings of the National Academy of Sciences of the United States of America 108(32):13281-13286.
Pew Research Center. 2013a. After Boston, little change in views of Islam and violence. Washington, DC: Pew Research Center. http://www.people-press.org/2013/05/07/after-bostonlittle-change-in-views-of-islam-and-violence/ (accessed October 15, 2014).
Pew Research Center. 2013b. For African Americans, discrimination is not dead. Washington, DC: Pew Research Center. http://www.pewresearch.org/fact-tank/2013/06/28/for-africanamericans-discrimination-is-not-dead/ (accessed September 26, 2014).
Priest, N., Y. Paradies, B. Trenerry, M. Truong, S. Karlsen, and Y. Kelly. 2013. A systematic review of studies examining the relationship between reported racism and health and wellbeing for children and young people. Social Science & Medicine 95:115-127.
Raznahan, A., P. W. Shaw, J. P. Lerch, L. S. Clasen, D. Greenstein, R. Berman, J. Pipitone, M. M. Chakravarty, and J. N. Giedd. 2014. Longitudinal four-dimensional mapping of subcortical anatomy in human development. Proceedings of the National Academy of Sciences of the United States of America 111(4):1592-1597.
Rindfuss, R. R., C. G. Swicegood, and R. A. Rosenfeld. 1987. Disorder in the life course—how common and does it matter. American Sociological Review 52(6):785-801.
Roisman, G. I., A. S. Masten, J. D. Coatsworth, and A. Tellegen. 2004. Salient and emerging developmental tasks in the transition to adulthood. Child Development 75(1):123-133.
SAMHSA (Substance Abuse and Mental Health Services Administration). 2009. Results from the 2008 National Survey on Drug Use and Health: National findings. Rockville, MD: SAMHSA.
Scherf, K. S., J. M. Smyth, and M. R. Delgado. 2013. The amygdala: An agent of change in adolescent neural networks. Hormones and Behavior 64(2):298-313.
Schmitt, M. S., N. R. Branscombe, T. Postmes, and A. Barcia. 2014. The consequences of perceived discrimination for psychological well-being: A meta-analytic review. Psychological Bulletin 140:921-948.
Schneider, B. 2007. Forming a college-going community in U.S. public high schools. Lansing: Michigan State University.
Schulenberg, J. E., and J. L. Maggs. 2002. A developmental perspective on alcohol use and heavy drinking during adolescence and the transition to young adulthood. Journal of Studies on Alcohol 14:54-70.
Schulenberg, J. E., and I. Schoon. 2012. The transition to adulthood across time and space: Overview of special section. Longitudinal and Life Course Studies 3(2):164-172.
Seidman, L. J. 2013. Mental health—psychotic disorders. Presentation at IOM/NRC Workshop on Improving the Health, Safety, and Well-Being of Young Adults, Washington, DC. http://www.iom.edu/~/media/Files/Activity%20Files/Children/ImprovingYoungAdultsHealth/Seidman%20Presentation.pdf (accessed October 10, 2014).
Seltzer, J. A. 2000. Families formed outside of marriage. Journal of Marriage and Family 62(4):1247-1268.
Settersten, R. A., and B. Ray. 2010. Not quite adults: Why 20-somethings are choosing a slower path to adulthood, and why it’s good for everyone. 1st ed. New York: Delacorte Press.
Shanahan, M. J. 2000. Pathways to adulthood in changing societies: Variability and mechanisms in life course perspective. Annual Review of Sociology 26:667-692.
Simmonds, D., M. N. Hallquist, M. Asato, and B. Luna. 2013. Developmental stages and sex differences of white matter and behavioral development through adolescence: A longitudinal diffusion tensor imaging (DTI) study. NeuroImage 92:356-368.
Smith, A. R., J. Chein, and L. Steinberg. 2013. Impact of socio-emotional context, brain development, and pubertal maturation on adolescent risk-taking. Hormones and Behavior 64(2):323-332.
Smith, E. L., and A. Cooper. 2013. Homicide in the U.S. known to law enforcement, 2011. Washington, DC: Bureau of Justice Statistics.
Somerville, L. H., and B. Casey. 2010. Developmental neurobiology of cognitive control and motivational systems. Current Opinion in Neurobiology 20(2):236-241.
Sowell, E. R., P. M. Thompson, C. J. Holmes, T. L. Jernigan, and A. W. Toga. 1999. In vivo evidence for post-adolescent brain maturation in frontal and striatal regions. Nature Neuroscience 2(10):859-861.
Sowell, E. R., B. S. Peterson, P. M. Thompson, S. E. Welcome, A. L. Henkenius, and A. W. Toga. 2003. Mapping cortical change across the human life span. Nature Neuroscience 6(3):309-315.
Spear, L. P. 2000. Neurobehavioral changes in adolescence. Current Directions in Psychological Science 9(4):111-114.
Steinberg, L. 2013. Psychological development in young adulthood. Presentation at IOM/NRC Workshop on Improving the Health, Safety, and Well-Being of Young Adults, Washington, DC.
Steinberg, L., D. Albert, E. Cauffman, M. Banich, S. Graham, and J. Woolard. 2008. Age differences in sensation seeking and impulsivity as indexed by behavior and self-report: Evidence for a dual systems model. Developmental Psychology 44:1764-1778.
Stone, J., A. Berrington, and J. Falkingham. 2013. Gender, turning points, and boomerangs: Returning home in young adulthood in Great Britain. Demography 51:257-276.
Teachman, J. D., L. M. Tedrow, and K. D. Crowder. 2000. The changing demography of America’s families. Journal of Marriage and Family 62(4):1234-1246.
Turkle, S. 2011. Together alone: Why we expect more from technology and less from each other. New York: Basic Books.
U.S. Census Bureau. 2010. Foreign-born population in the United States, 2010. Washington, DC: U.S. Department of Commerce. http://www.census.gov/prod/2012pubs/acs-19.pdf (accessed October 10, 2014).
U.S. Census Bureau. 2012. 2012 national population projections. http://www.census.gov/population/projections/data/national/2012.html (accessed October 16, 2014).
U.S. Department of Education and National Center for Education Statistics. 2014. The condition of education 2014 (NCES 2014-083). http://nces.ed.gov/pubs2014/2014083.pdf (accessed October 10, 2014).
van Leijenhorst, L., B. G. Moor, Z. A. Op de Macks, S. A. Rombouts, P. M. Westenberg, and E. A. Crone. 2010. Adolescent risky decision-making: Neurocognitive development of reward and control regions. NeuroImage 51(1):345-355.
Wahlstrom, D., P. Collins, T. White, and M. Luciana. 2010. Developmental changes in dopamine neurotransmission in adolescence: Behavioral implications and issues in assessment. Brain and Cognition 72(1):146-159.
Wegrzyn, C. 2014. Social media and information technology. Presentation at IOM/NRC Workshop on Improving the Health, Safety, and Well-Being of Young Adults: State Policies and Programs and Social Media and Information Technology, Washington, DC.
Whitsel, E. A., Q. C. Nguyen, C. Suchindran, J. M. Hussey, L. A. Killeya-Jones, J. W. Tabor, C. S. Fitzgerald, S. P. Hallquist, C. T. Halpern, and K. M. Harris. 2011. Value added quality, quantity, and diversity of national blood pressure data on young adults. Epidemiology 22(4):544-545.
Whitsel, E. A., Q. C. Nguyen, C. Suchindran, J. W. Tabor, C. C. Cuthbertson, M. H. Wener, A. J. Potter, L. Killeya-Jones, J. M. Hussey, C. T. Halpern, and K. M. Harris. 2012. Dried capillary whole blood spot-based hemoglobin A1c, fasting glucose, and diabetes prevalence in a nationally representative population of young U.S. adults: Add Health, wave IV. Circulation 125:AP010.
Wierenga, L., M. Langen, S. Ambrosino, S. van Dijk, B. Oranje, and S. Durston. 2014. Typical development of basal ganglia, hippocampus, amygdala and cerebellum from age 7 to 24. NeuroImage 96:67-72.
Williams, D., and R. Williams-Morris. 2000. Racism and mental health: The African American experience. Ethnicity and Health 5(3-4):243-268.
Williams, D. R., H. W. Neighbors, and J. S. Jackson. 2003. Racial/ethnic discrimination and health: Findings from community studies. American Journal of Public Health 93(2): 200-208.
Zagorsky, J. L., and P. K. Smith. 2011. The freshman 15: A critical time for obesity intervention or media myth? Social Science Quarterly 92(5):1389-1407.