Stress Burden and the Lifetime Incidence of Psychiatric Disorder inYoung Adults

BACKGROUND: With the exception of studies of individual traumatic events, the significance of stress exposure in psychiatric disorder previously has not been effectively examined. OBJECTIVE: To address the hypothesis that accumulated adversity represents an important risk factor for the subsequent onset of depressive and anxiety disorders. DESIGN: A community-based study of psychiatric and substance use disorders among a large, ethnically diverse cohort representative of young adults in South Florida. Adversity was estimated with a count of major and potentially traumatic events experienced during one's lifetime and prior to the onset of disorder. SETTING: Most interviews took place in the homes of participants, with 30% conducted by telephone. PARTICIPANTS: We obtained a random sample of individuals aged 18 to 23 years from a previously studied representative sample of young adolescents. Because participants in the prior study were predominantly boys, a supplementary sample of girls was randomly obtained from the early-adolescence school class rosters. A total of 1803 interviews were completed, representing a success rate of 70.1%. MAIN OUTCOME MEASURES: Depressive and anxiety disorders were assessed through computer-assisted personal interviews using the DSM-IV version of the Michigan Composite International Diagnostic Interview. RESULTS: Level of lifetime exposure to adversity was found to be associated with an increased risk of subsequent onset of depressive and/or anxiety disorder. This association remained clearly observable when childhood conduct disorder, attention-deficit/hyperactivity disorder, prior substance dependence, and posttraumatic stress disorder were held constant and when the possibility of state dependence effects was considered. CONCLUSION: Evidence suggests that high levels of lifetime exposure to adversity are causally implicated in the onset of depressive and anxiety disorders.