Sex differences in posttraumatic stress disorder.

BACKGROUND: Epidemiologic surveys in the general population documented a higher rate of posttraumatic stress disorder (PTSD) in women than in men. To date, the finding has received little scientific attention. This study examines the extent to which sex differences in PTSD might be explained by previously identified risk factors and whether the sex difference in PTSD varied by age at exposure to traumatic events.

METHODS: The NIMH-DIS (NIMH Diagnostic Interview Schedule, Version III Revised) was used to measure DSM-IIIR disorders in a random sample of 1007 young adults. Cox proportional hazards models were used to estimate changes in the hazards ratio for PTSD associated with sex when potential risk factors were included.

RESULTS: Lifetime prevalence of exposure to traumatic events and number of traumatic events did not vary by sex. The prevalence of PTSD was higher for women than for men exposed to traumatic events (hazards ratio, 2.3; 95% confidence interval, 1.5-3.6). Preexisting anxiety disorders or major depressive disorders played a part in the observed sex difference in PTSD. Family history of anxiety disorder and early separation from parents, although significant risk factors for PTSD in subjects of both sexes, were unrelated to the sex difference in PTSD. The sex difference in PTSD was markedly greater if exposure occurred in childhood than later on.

CONCLUSIONS: Posttraumatic stress disorder is more likely to develop in females than in males after exposure to a traumatic event. Susceptibility to PTSD in females might be greater in childhood than after age 15 years. Explanations of the sex difference might involve characteristics of individuals and of the traumatic experiences.