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.
