families living in poverty in 2004 varied from 5.3 percent in Minnesota to 17.6 percent in Mississippi.
In order to focus prevention efforts most effectively, it is essential to know when vulnerability to an emotional or behavioral disorder increases simply with an increasing number of risk factors, irrespective of their nature, and when increased risk follows specific risk exposures. (Of course, both may occur at the same time.) We illustrate how both aspects of risk come into play with data from over 6,000 assessments of 1,420 youth from the GSMS. On one hand, there was a clear relationship between total risk exposure, using a list of over 80 risk factors, and MEB disorders. Rates of nearly all of these disorders were three or more times higher in the highest risk group than in the lowest risk group, irrespective of the type of risk.
On the other hand, when the question of specific risk factors for specific disorders was examined in the same data set, both general and disease-specific risk factors emerged (Shanahan and Hofer, 2005). Parental unemployment and maternal depression were associated with increased risk for most MEB disorders, but the analyses revealed “signature sets” of factors associated only with certain diagnoses. For example, while sexual abuse, poor parental supervision, and deviant peers were risk factors for both conduct disorder and oppositional defiant disorder, parental depression and loss of close relations and friends were specific to conduct disorder in these analyses. In the emotional disorders, parental depression was a specific risk for depression but was not associated with any anxiety disorders, whereas parental drug use and unemployment were associated with anxiety disorders but not with depression (see also Chapter 4).
The role of individual differences in genetic makeup has been the focus of intensive study in recent decades (see Chapter 5). Twin and adoption studies have identified a genetic component of risk for most child and adolescent psychiatric2 disorders (Rutter, Silberg, et al., 1999a, 1999b), and genetic research in psychiatry began with the hypothesis that genes “cause” mental illness (Kendler, 2005). However, with the exception of a number of rare disorders, such as Williams syndrome, Turner syndrome, fragile X syndrome, and velocardiofacial syndrome (Davies, Isles, and Wilkinson, 2001; Inoue and Lupski, 2003; Thapar and Stergiakouli, 2008) so far no unequivocal candidate genes for specific mental, emotional, or behavioral disorders in children or adults have survived the test of replication in multiple studies (Joober, Sengupta, and Boksa, 2005; Thapar and Stergiakouli, 2008). There are some indications that variations in specific genes may contribute to such disorders as depression (Levinson, 2006; Lopez-Leon, Janssens, et al., 2008).