Childhood adversity, adult stressful life events, and risk of past-year psychiatric disorder: a test of the stress sensitization hypothesis in a population-based sample of adults.

BACKGROUND Childhood adversity (CA) is associated with adult mental disorders, but the mechanisms underlying this association remain inadequately understood. Stress sensitization, whereby CA increases vulnerability to mental disorders following adult stressful life events, has been proposed as a potential mechanism. We provide a test of the stress sensitization hypothesis in a national sample. METHOD We investigated whether the association between past-year stressful life events and the 12-month prevalence of major depression, post-traumatic stress disorder (PTSD), other anxiety disorders, and perceived stress varies according to exposure to CA. We used data from the National Epidemiological Survey of Alcohol and Related Conditions (NESARC) (n=34 653). RESULTS Past-year stressful life events were associated with an increased risk of major depression, PTSD, anxiety disorders, and perceived stress. However, the magnitude of the increased risk varied according to respondents' history of CA. For example, past-year major stressors were associated with a 27.3% increase in the 12-month risk of depression among individuals with 3 CAs and a 14.8% increased risk among individuals without CAs. Stress sensitization effects were present for depression, PTSD, and other anxiety disorders in women and men, although gender differences were found in the threshold of past-year stress needed to trigger such effects. Stress sensitization was most evident among individuals with 3 CAs. CONCLUSIONS CA is associated with increased vulnerability to the deleterious mental health effects of adult stressors in both men and women. High levels of CA may represent a general diathesis for multiple types of psychopathology that persists throughout the life course.