Objective: Marijuana abuse, primarily a disorder of adolescents and young adults, is highly prevalent among patients with severely ill psychiatric population, especially those with bipolar disorder. Additional marijuana abuse may impact on the clinical presentation of bipolar illness and may potentially act as mediator of treatment response in this population. However, the characterization of bipolar disorder patients with additional marijuana abuse and the impact of such abuse on treatment outcome has been rarely examined. The aim of this study was to characterize bipolar alcoholic patients with comorbid marijuana abuse and test the impact of marijuana abuse on alcohol and mood outcome of patients with bipolar disorder and comorbid alcohol dependence.
Method: We conducted secondary analyses of a randomized, double blind, placebo-controlled trial testing valproate in 52 bipolar alcoholics. Subjects had a comprehensive assessment at baseline using structured diagnostic assessments, and they were then assessed every 2 weeks for 24 weeks.
Results: Twenty-five subjects (48%) reported marijuana abuse. Those with co-occurring marijuana abuse were younger, had fewer years of education, and had significantly higher number of additional psychiatric comorbidity. They also had more severe alcohol and other drug use and were significantly more likely to present in the manic phase. The mixed model indicated that the placebo-treated marijuana abuse group had the worst alcohol use outcome.
Conclusions: Marijuana abuse among patients with bipolar disorder and alcohol dependence is associated with higher degree of severity of alcohol and other drugs of abuse and may negatively impact on alcohol treatment outcome.