Precise estimates of the size of the problem of MEB disorders of youth in the United States, or changes in the problem over time, require nationally representative population surveys that make valid and reliable diagnoses. However, as discussed below, the consensus from a large number of recent studies with smaller samples or from other countries provides a ballpark estimate.

Clinical psychiatry has mapped out a range of MEB disorders and related problems seen in children and adolescents. These are listed in the two main taxonomies of disease, the section on mental and behavioral disorders in the International Statistical Classification of Diseases and Related Health Problems (ICD) (World Health Organization, 1993) and the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) (American Psychiatric Association, 1994). Some other major public health problems, like crime and violence, are subsumed within the diagnostic criteria for conduct disorder. The disorders examined in this chapter are those in the American Psychiatric Association’s DSM-IV. The DSM-IV includes abuse of and dependence on alcohol and illicit drugs, as well as dependence on tobacco.

This section reviews current epidemiological information about the more common MEB disorders up to age 25: conduct disorder and oppositional defiant disorder, often combined as disruptive behavior disorders; attention deficit hyperactivity disorder (ADHD); anxiety disorders, including posttraumatic stress disorder; depression; and drug abuse and dependence. Disorders of low population frequency, with little reliable epidemiological data but considerable societal burden—such as autism spectrum disorders and pervasive developmental disorders, schizophrenia, bipolar disorder, eating disorders, and obsessive compulsive disorder—are discussed when information is available. More specific information may be available when the adolescent version of the NCS is published.

Table 2-2 presents the results of a meta-analysis of data on the prevalence of MEB disorders in young people from more than 50 community surveys from around the world, published in the past 15 years (updated from Costello, Mustillo, et al., 2004). The analysis controlled for sample size, number of prior months that subjects were asked about in reporting their symptoms, and age of participants. Not all studies report on all diagnoses. The table includes the 16 diagnoses or diagnostic groupings that were reported by at least 8 studies (number of studies shown in parentheses).

Figure 2-1 illustrates with a box-and-whisker plot the range of estimates from these surveys for each diagnosis. The ends of the “whiskers” for each