Effect of alcohol use on the course of bipolar disorder: one-year follow-up study using the daily prospective Life Chart method.

Objectives: Relatively little is known about the temporal relationship between alcohol use and subsequent mood changes in patients with bipolar disorder, and the available findings are inconsistent. The present study was a fine-grained analysis of the temporal relationship between alcohol use and short-term mood-switching probabilities.

Methods: The study included 137 patients with bipolar disorder who performed daily self-ratings of their mood symptoms and the number of alcohol units consumed for a period of up to 52 weeks by using the National Institute of Mental Health self-rated prospective Life Chart Method. At baseline, the Structured Clinical Interview for DSM-IV was administered and demographic, social, and clinical characteristics were obtained. Multi-state models were used to assess the impact of the number of alcoholic drinks on patients' transition through different states of mood (depression, euthymia, and mania).

Results: The effect of alcohol use on the change in mood states was limited. For women in a depressive state, higher alcohol use was associated with a shorter time before entering the euthymic state [hazard ratio (HR) = 1.18, 95% confidence interval (CI): 1.03-1.36, p < 0.05], whereas, for men in an euthymic state, higher alcohol use was associated with a longer time before entering a manic state (HR = 0.81, 95% CI: 0.71-0.92, p < 0.05). The correlation between the consumed number of drinks per week and the average mood severity score of the following week was -0.01 (p < 0.001), indicating that only 0.01% of the variance in mood severity in this population is explained by alcohol use. Possible explanations for these findings are discussed.

Conclusions: The current study, using a fine-grained analysis, suggests that alcohol use does not have a direct effect on the course of bipolar disorder in patients using mood stabilizers.