Risks for the transition from major depressive disorder to bipolar disorder in the National Epidemiologic Survey on Alcohol and Related Conditions.

OBJECTIVE

It is currently not possible to determine which individuals with unipolar depression are at highest risk for a manic episode. This study investigates clinical and psychosocial risk factors for mania among individuals with major depressive disorder (MDD), indicating diagnostic conversion from MDD to bipolar I disorder.

METHOD

We fitted logistic regression models to predict the first onset of a manic episode among 6,214 cases of lifetime MDD according to DSM-IV criteria in the National Epidemiologic Survey on Alcohol and Related Conditions. Participants in this survey were interviewed twice over a period of 3 years, in 2000-2001 and in 2004-2005, and survey data were gathered using the Alcohol Use Disorder and Associated Disabilities Interview Schedule-IV.

RESULTS

Approximately 1 in 25 individuals with MDD transitioned to bipolar disorder during the study's 3-year follow-up period. Demographic risk factors for the transition from MDD to bipolar disorder included younger age, black race/ethnicity, and less than high school education. Clinical characteristics of depression (eg, age at first onset, presence of atypical features) were not associated with diagnostic conversion. However, prior psychopathology was associated with the transition to bipolar disorder: history of social phobia (odds ratio [OR] = 2.20; 95% confidence interval [CI], 1.47-3.30) and generalized anxiety disorder (OR = 1.58; 95% CI, 1.06-2.35). Lastly, we identified environmental stressors over the life course that predicted the transition to bipolar disorder: these include a history of child abuse (OR = 1.26; 95% CI, 1.12-1.42) and past-year problems with one's social support group (OR = 1.79; 95% CI, 1.19-2.68). The overall predictive power of these risk factors based on a receiver operating curve analysis is modest.

CONCLUSIONS

A wide range of demographic, clinical, and environmental risk factors were identified that indicate a heightened risk for the transition to bipolar disorder. Additional work is needed to further enhance the prediction of bipolar disorder among cases of MDD and to determine whether interventions targeting these factors could reduce the risk of bipolar disorder.