Our results clearly demonstrate that a large percentage of young people from at-risk communities enter adulthood with serious adversity in their pasts. High school seniors in this sample suffered high levels of exposure to ACEs during their lifetimes, most likely due to the urban, socio-economically disadvantaged character of the communities in this study. Rates of most ACEs reported by girls and boys in this sample exceed estimates of ACEs occurring before age 16 in the NCS sample [
2], in a rural North Carolina (NC) sample [
20], and in a mostly white, lower middle class sample [
8], although they appear to be lower than those in the Singer et al. [
6] high school sample. In addition, our results highlight the importance of race as a risk factor for exposure to certain types of ACEs. The higher prevalence estimates reported in the present study are almost certainly a function of the greater racial/ethnic diversity relative to previous studies (e.g. [
22,
36]).
The public health impact of such high levels of exposure to childhood adversities is evident in their strong and pervasive affects on mental health in early adulthood. Substantial effect sizes for events such as sexual abuse/assault and physical abuse and assault were observed, providing further evidence of the especially pernicious effects of child maltreatment and violence on mental health [
3,
6,
11]. In addition, the pervasive nature of these effects–only 1 of the 10 ACEs examined was not significantly associated with multiple mental health outcomes–is consistent with previous research that found little evidence for specificity in the effects of adverse events in the etiology of mental disorders [
2,
6,
10,
11,
16]. Our results replicate and strengthen a number of prior studies revealing the broad-based impact of ACEs on depressive symptoms and drug use in early adulthood [
15,
37], although the association of ACEs with antisocial behavior in this period of life is to our knowledge a novel finding. While novel, this latter finding was not wholly unanticipated, as it supports Widom's assertion that childhood victimization may be an important cause of juvenile delinquency [
38]. Taken together, these findings, coupled with other evidence that the impact of major childhood adversities persists well into adulthood, indicate the critical need for prevention and intervention strategies targeting early adverse experiences and their mental health consequences.
Because the transition to adulthood is a watershed developmental period, the mental health consequences of ACEs are likely to have far-reaching impact by disrupting the establishment of positive roles and relationships that set the course for adult occupational and social attainment [
31,
39]. However, understanding the ways in which the mental health consequences of early adversity impact both the selection of and ability to function in young adult roles may provide promising avenues for effective intervention. Because of the fluidity and malleability of roles during this period (see [
40]), the transition to adulthood offers a potential "turning point" in the lives of disadvantaged youth. For example, previous research has shown that both post-secondary education and supportive romantic relationships positively influence the lifecourse trajectories of at-risk young adults [
41-
45]. Moreover, these roles are likely synergistic in their influence: One of the benefits of higher education in women is that it delays establishment of committed romantic relationships, resulting in higher quality marriages [
43,
44] which promote better mental health [
46]. Clearly, strategies for preventing serious childhood adversity would be most beneficial: however, the malleability of young adulthood may provide additional opportunities to re-direct lifecourse trajectories in a positive direction and to prevent the adult mental health consequences of ACEs.
Although some gender differences in the impact of ACEs on mental health in young adults were found, our findings, taken as a whole, suggest that the contention that child abuse results in gender-typical psychopathology [
47] is not so clear-cut. Young men are equally as likely as young women to exhibit depressive symptoms in response to ACEs. In addition, although the impact of ACEs on antisocial behavior was generally much stronger among young men, young women exposed to some ACEs do exhibit elevated levels of antisocial behavior. We did find one noteworthy gender difference, however. Sexual abuse/assault is associated with much higher levels of drug use, depressive symptoms and antisocial behavior in young men than in young women. Our results were based on a very small sample of sexually victimized boys, so this finding needs to be viewed with caution. Nevertheless, because the impact of sexual abuse among boys is understudied, this result underlines the need for further longitudinal research on the impact of sexual abuse/assault among boys.
To our knowledge, our study is the first to investigate racial/ethnic differences in the impact of a variety of ACEs on a variety of outcomes for the three most prevalent racial/ethnic groups in the US. Our results indicate that when racial/ethnic differences exist, young Whites consistently exhibit greater vulnerability to ACEs, particularly for externalizing behaviors. One explanation is that these results may illustrate a "steeling effect" [
48] in which youths in some ethnic groups are better able to successfully cope with stress and adversity and are consequently less prone to mental health difficulties. Research on coping processes may provide support for this explanation, as there is evidence that cognitive coping styles more typical among ethnic subcultures may explain differential racial/ethnic vulnerability to stress [
26]. For example, differences in coping styles partially explain greater vulnerability to PTSD among Hispanic compared to Black and White police officers (see [
27]), and greater religiosity, found among Blacks compared to Whites, has been found to be protective [
49].
Finally, the limitations of our study need to be noted. While our response rates were high for the original survey of respondents, as well as for the follow-up, the differential attrition of Hispanic and Black respondents relative to Whites is a limitation. In addition, despite the use of multiple waves of data to separate predictors from outcomes, the direction of causality between ACEs and mental health may be tenuous. This is particularly true for antisocial behavior and drug use, both of which may increase exposure to some types of ACEs; moreover a complicated, non-recursive relationship between ACEs and childhood antisocial/drug activity may exist (see [
19] for discussion of this issue). Finally, consistent with other studies investigating the relationship between ACEs and mental health [
2,
6,
8], we did not take into account the age at which the adversities occurred in our analysis. Although this is clearly an important factor in determining their developmental impact (see [
19]), we were unable to consider age at occurrence because of the low frequency of occurrence of these ACEs in our data. This is an important avenue for future study.