Population attributable fractions of psychiatric disorders and suicide ideation and attempts associated with adverse childhood experiences

Objectives. We sought to determine the fractions of psychiatric disorders and suicide ideation and attempts in a general population sample attributable to childhood physical abuse, sexual abuse, and witnessing domestic violence.Methods. Data were obtained from the US National Comorbidity Survey Replication. Population attributable fractions were calculated to determine the proportion of psychiatric disorders and suicide ideation and attempts attributable to adverse childhood experiences. The analysis was stratified by gender.Results. The estimated attributable fractions for psychiatric disorders attributable to having experienced any adverse childhood event ranged from 22% to 32% among women and 20% to 24% among men. Having experienced any adverse event accounted for a substantial proportion of suicide ideation and attempts among women (16% and 50%, respectively) and men (21% and 33%, respectively). Substantial proportions of poor mental health outcomes were also attributable to increasing number of adverse events.Conclusions. The estimated proportions of poor mental health outcomes attributed to childhood adversity were medium to large for men and women. Prevention efforts that reduce exposure to adverse childhood events could substantially reduce the prevalence of psychopathology and suicidal behavior in the general population.Past research has established a strong association between exposure to childhood adversity and increased likelihood of psychiatric disorders1^–5 and suicidal behavior6^,7 in adulthood. In addition, when one looks at adverse childhood events along a continuum, a dose–response group relationship has been found with increasing severity of childhood adversity corresponding with poorer mental health outcomes.8 Although the relationship between childhood adversity and poor adult mental health is widely accepted, there is little information on what proportion of psychiatric disorders and suicidal behavior is attributable to adverse childhood experiences in the general population.To date, only a few published studies have calculated population attributable fractions to estimate the proportion of psychiatric disorders and suicidality associated with adverse childhood experiences. In a study of a community sample, Scott found that 3.9% of psychiatric cases were attributable to childhood sexual abuse.9 Dube et al. used a clinic sample to assess the relationship between several adverse childhood experiences and illicit drug use and found that 56% of lifetime drug problems, 63% of illicit drug addiction, and 64% of intravenous drug use was attributable to having experienced at least 1 adverse childhood event.10 In a different study, Dube et al., using the same data, found that 67% of lifetime suicide attempts, 80% of child or adolescent suicide attempts, and 64% of adult suicide attempts were attributable to having experienced 1 or more adverse childhood events.11 Finally, Molnar et al. found that after they controlled for the effects of psychiatric disorders and other adverse childhood experiences, 8% to 12% of serious suicide attempts were attributable to childhood sexual abuse in a nationally representative US sample.7The proportion of poor mental health outcomes attributable to adverse childhood experiences varies substantially from one study to another. At least some of this variation can be explained on methodological grounds. The size of the attributable fraction depends on the prevalence of the exposure in the population and the strength of association between the exposure and outcome variable.12 In the 2 studies in which the authors reported high attributable fractions, broad definitions of any childhood events were used, including experiences such as parental divorce, which resulted in more than 60% endorsement of childhood adversity in the clinical sample.10^,11 The high prevalence of adverse childhood events would contribute to the large estimated attributable fractions. Another explanation for the large attributable fractions in the study in which childhood adversity and suicide were examined was that the authors controlled for depressed affect, self-reported alcoholism, and illicit drug use with single items, but did not control for psychiatric disorders.11 Failure to control for psychiatric disorders when assessing the relationship between childhood adversity and suicide attempts would inflate associations and contribute to larger estimates of attributable fractions.Conversely, other studies have shown lower attributable fractions, which are more common in epidemiological studies. The low attributable fraction in Scott’s9 research may be partly because of the suspected underestimation of the prevalence of childhood sexual abuse, which led the author to conclude that the relationship between childhood sexual abuse and psychiatric disorders may be stronger than the results indicated. Lower attributable fractions reported by Molnar et al.7 were likely attributable to the inclusion of important covariates in the models.In addition to the aforementioned methodological discrepancies in previous studies, other methodological limitations of past research have included the calculation of attributable fractions for only 1 type of childhood adversity,7^,9^,13 the assessment of only 1 category of mental health outcome,7^,10^,11^,13 the estimation of attributable fractions for females only13 or males and females combined without the consideration of possible gender differences,10^,11 the failure to evaluate the impact of potentially important covariates,9 and the lack of nationally representative general population samples.9^–11 We addressed the limitations of past research with the inclusion of numerous childhood adversities and mental health outcomes, the stratification of the analyses based on gender, the inclusion of important covariates, and the use of a contemporary nationally representative sample.We sought to estimate the population attributable fractions for each group of psychiatric disorders (any mood disorder, any anxiety disorder, any substance use disorder, and any psychiatric disorder) and suicidal behavior (ideation and attempts) among men and women attributable to childhood physical abuse, childhood sexual abuse, having witnessed domestic violence, and the number of adverse childhood events experienced after adjustment for important covariates.