Substance use disorders increase the odds of subsequent mood disorders.

Background: There is a well-known association between mood disorders and substance use disorders (SUD), but little research has been conducted on SUDs as risk factors for the development of subsequent mood disorders.

Methods: We analyzed data from the National Comorbidity Survey Replication study. Diagnoses were determined using DSM-IV criteria. Odds ratios (aORs) of subsequently developing mood disorders were adjusted for age, sex and race/ethnicity.

Results: Data from 5217 individuals were included (6.6% male; mean age 45.3 years; 72.6% White, 11.2% Black, 12.5% Hispanic and 3.7% other). Subsequent mood disorders developed in 26.4% of individuals with primary adolescent-onset SUD (12-17 years), 21.7% of those with SUD onset at 18-25 years, and 14.0% of those with SUD onset between the ages of 26 and 34 years. The mean lagtime between SUD onset and development of a mood disorder was about 11 years. Controlling for demographic variables, the aORs of developing a mood disorder in these three age groups were 2.44, 3.65, and 3.25. Substance dependence was associated with higher odds of mood disorders than was abuse. Among the specific mood disorders, the increased odds of developing bipolar disorder were particularly high among individuals with drug dependence.

Conclusions: Individuals with adolescent and young adult-onset SUD had increased odds of developing a secondary mood disorder. This indicates that adolescents and young adults with SUD should be closely monitored for both positive and negative mood symptoms. SUD treatment and aftercare offer opportunities for the early identification of secondary mood disorders.