Comorbid disorders in patients with bipolar disorder and concomitant substance dependence

Objective: Substance dependence is common in bipolar disorder and is associated with an increase in Axis I and II comorbidity. Little research has compared the relative rates of comorbidity among bipolar patients with dependence on different substances. Methods: The Mini International Neuropsychiatric Interview (MINI) was used to assess 166 outpatients involved in one of three clinical trials of medications for bipolar disorder and substance dependence. Patients had concurrent alcohol dependence, cocaine dependence, or both conditions. Results: Generalized anxiety disorder and current depressed mood were significantly more common in bipolar patients with alcohol dependence than bipolar patients with cocaine dependence. Those with cocaine dependence had significantly higher rates of post-traumatic stress disorder and antisocial personality disorder and were more likely to present in a mixed mood state than patients dependent on alcohol. Cocaine ENC dependent patients were more likely than alcohol dependent patients to have Bipolar I relative to Bipolar II. Limitations: This is a retrospective, cross-sectional data analysis using the MINI for diagnosis. Conclusions: Cocaine dependence and alcohol dependence were associated with different clinical features and comorbid disorders in bipolar patients. The results may help confirm the validity of integrative models of mood, behavioral, anxiety, and personality disorders. Further studies on the causal relationship between substance dependence and concurrent and lifetime Axis I disorders for patients with bipolar disorders are indicated.