Predictors of first lifetime onset of major depressive disorder in young adulthood.

The first onset of major depressive disorder (MDD) most frequently occurs in young adulthood. However, few studies have examined predictors of first lifetime MDD during this high-risk period. The present study examined a broad range of demographic, clinical, and psychosocial variables as prospective predictors of first onset of MDD in a large community sample of young adults (N = 502) from the Oregon Adolescent Depression Project. Between ages 19-31, 35.3% of the sample had a first lifetime MDD episode. Female gender, familial loading of mood disorders, history of childhood sexual abuse, prior history of anxiety disorder, poor self-reported physical health, and subthreshold depressive symptoms significantly predicted MDD onset. In a multivariate model, female gender, familial loading of mood disorders, and subthreshold depression each contributed unique variance in predicting first lifetime MDD. This model had a moderate-to-large effect in predicting MDD onset. Gender did not moderate the other predictors, and the magnitude of the effects did not diminish over the course of the follow-up. These findings indicate that a number of risk factors significantly predict first lifetime MDD in young adulthood, and that simple multivariate risk models may be useful for identifying individuals at high risk for MDD.