The impact of substance abuse on the course of bipolar disorder.

BACKGROUND Substance abuse occurs at high rates in bipolar disorder. The reasons for this co-occurrence are unknown. Alcohol use disorders have been associated with both earlier and later age of onset of bipolar disorder, in part based on the temporal associations of the two conditions. Both drug and alcohol use disorders are associated with impaired outcome of bipolar illness. This influence may involve both direct effects of alcohol or drugs on the initiation of affective symptoms and indirect effects on treatment compliance. To extend these previous findings we examined the temporal associations of substance abuse and affective symptoms in patients with new onset bipolar disorder. METHODS Associations between affective symptoms and alcohol and cannabis use disorder symptoms were evaluated using regression and time-series correlative methods in 50 new-onset bipolar patients. RESULTS The duration of alcohol abuse during follow-up was associated with the time patients experienced depression. The duration of cannabis abuse was associated with the duration of mania. Several subgroups could be identified with different temporal relationships among these disorders. CONCLUSIONS Although the relationships among substance use and bipolar disorders are complex, systematic study of the courses of the disorders might clarify how these conditions interact longitudinally. As the numbers of subjects in specific subgroups are relatively small in this study, these results should be considered preliminary.