The effect of moderate and excessive alcohol use on the course and outcome of patients with bipolar disorders: a prospective cohort study.

OBJECTIVE

Comorbid alcohol use disorders (AUDs) are frequently associated with negative effects on course and outcome of bipolar disorder. This prospective cohort study assessed the effect of actual alcohol use (no, moderate, and excessive) on the course and outcome of patients with bipolar disorders.

METHOD

Between June 2003 and November 2005, 137 outpatients (aged 23-68 years) with DSM-IV-diagnosed bipolar I (66%) or II (34%) disorder rated their mood and the number of alcohol units consumed daily for a period up to 52 weeks with the National Institute of Mental Health Self-Rating Prospective Life-Chart Method (LCM). At baseline, the Structured Clinical Interview for DSM-IV was administrated, and demographic, social, and clinical characteristics were obtained. At monthly visits, the Clinical Global Impressions Scale-Bipolar Version (CGI-BP), the Global Assessment of Functioning (GAF) scale, and the Medical Outcomes Study 36-Item Short-Form Health Survey (MOS-SF-36) were rated. Based on the alcohol use in the first 4 weeks of follow-up, patients were assigned to 1 of 3 groups: no/incidental, moderate, or excessive alcohol use.

RESULTS

None of the sociodemographic and clinical characteristics at baseline were significantly different between the 3 drinking groups, with the exception of-and as a consequence of the group assignment-the prevalence of lifetime and current diagnosis of AUD. Also, no differences between the 3 drinking groups were found on any of the clinical outcome variables, ie, number of days ill (depressed, hypomanic/manic, and total); severity of depression, mania, and overall bipolar illness (LCM); GAF score; CGI-BP (depression, mania, and overall); and all the subscales of the MOS-SF-36. Also, the number of episodes according to DSM-IV and the Leapfrog method showed no significant differences between the drinking groups.

CONCLUSIONS

In this sample of patients and with the sensitive measurement of mood and drinking status over a full year, we could not confirm the findings of other studies indicating a negative effect of excessive alcohol use on the course of bipolar illness. This study found that neither moderate nor excessive use of alcohol has a negative effect on the course and outcome of bipolar illness. Possible explanations for these findings are discussed.