Generalized anxiety disorder, major depressive disorder, and their comorbidity as predictors of all-cause and cardiovascular mortality: the Vietnam experience study.

OBJECTIVE: To examine whether the 1-year prevalence of major depressive disorder (MDD), generalized anxiety disorder (GAD), and their comorbidity were associated with subsequent all-cause and cardiovascular disease (CVD) mortality during 15 years in Vietnam veterans.
METHODS: Participants (N = 4256) were from the Vietnam Experience Study. Service, sociodemographic, and health data were collected from service files, telephone interviews, and a medical examination. One-year prevalence of MDD and GAD was determined through a diagnostic interview schedule based on the Diagnostic and Statistical Manual of Mental Disorders (version IV) criteria. Mortality over the subsequent 15 years was gathered from US army records.
RESULTS: MDD and GAD were positively and significantly associated with all-cause and CVD mortality. The relationships between MDD and GAD and CVD mortality were no longer significant after adjustment for sociodemograhics, health status at entry, health behaviors, and other risk markers. Income was the covariate with the strongest impact on this association. In analyses comparing comorbidity and GAD and MDD alone, with neither diagnosis, comorbidity proved to be the strongest predictor of both all-cause and CVD mortality.
CONCLUSION: GAD and MDD predict all-cause mortality in a veteran population after adjusting for a range of covariates. However, those with both GAD and MDD were at greatest risk of subsequent death, and it would seem that these disorders may interact synergistically to affect mortality. Future research on mental disorders and health outcomes, as well as future clinical interventions, should pay more attention to comorbidity.