Substance Use Disorders in Bipolar Disorder: An Update Michael A. Cerullo, MD, and Stephen M. Strakowski, MD Corresponding author Michael A. Cerullo, MD Department of Psychiatry, University of Cincinnati College of Medicine, 231 Albert Sabin Way (ML0559), Cincinnati, OH 45267-0559, USA. E-mail: cerullmc@ucmail.uc.edu Current Psychosis & Therapeutics Reports 2006, 4:171–175 Current Science Inc. ISSN 1545-8083 Copyright © 2006 by Current Science Inc. Substance use disorders (SUDs) commonly co-occur during the course of bipolar type I disorder, and they can negatively affect illness outcome. This paper reviews recent research examining SUDs in bipolar disorder. These studies confirmed the high prevalence rate of SUDs but found that they are less common in younger patients (< age 17 years). Two new longitudinal studies suggest that a co-occurring SUD worsens the prognosis of bipolar disorder and leads to more affective symptoms and suicide attempts. Two new studies have examined the treatment of bipolar patients with a comorbid SUD. These studies suggest that valproate (as an adjunct to lithium) and aripiprazole may be useful in the treatment of the affective symptoms of bipolar patients with a comorbid SUD and may also help with the treatment of the SUD. Introduction Bipolar type I disorder is a serious psychiatric disorder that affects 1.5% of the US population [1]. The treatment of bipolar disorder is complicated by a high rate of co-occurring substance use disorders (SUDs). Regier et al. [2] found that among psychiatric illnesses, bipolar patients had the second highest rate of SUDs at 61% (compared with 17% for the general population, 47% for schizophrenia, and 27.2% for major depressive disorder); only antisocial personality disorder was higher at 84%. Prior research has highlighted the importance of co-occurring SUDs in bipolar disorder [3–5,8]. In the University of Cincinnati First-Episode Mania Study [3,4], Strakowski et al. [3] found that comorbid SUDs were associated with treatment noncompliance (which was associated with poorer outcome). Comorbid SUDs also have direct effects on outcome; after adjusting for compliance effects, patients with a SUD had delayed onset of symptomatic recovery [3]. Strakowski et al. [4] also found that the duration of alcohol abuse was positively correlated with the duration of depression and that the duration of cannabis abuse was positively correlated with the duration of mania. A long-term prospective study found that a history of alcohol use disorders (AUDs) in patients with bipolar was associ- ated with lower residential and occupational status [5]. In the McLean-Harvard First-Episode Mania Study [6,7], Tohen et al. [8] found that comorbid SUDs were associated with increased episodes of depression. Therefore, it is clear that comorbid SUDs are an important factor in understanding and treating bipolar disorder. There have been several new research stud- ies looking at this topic, and this article will focus on reports from 2005 and the first part of 2006 (Table 1). The first studies reviewed will be those that examined the epidemiology of SUD in bipolar patients. Next, we will review several studies that consider the effect of SUDs on the outcome of bipolar disorder. Finally, two studies that examined the treatment of bipolar disorder with comorbid SUDs will be reviewed. The Epidemiology of SUD in Bipolar Patients Five recent studies addressed epidemiologic questions regarding the co-occurrence of substance use and bipolar disorders. Using data from the McLean-Harvard First- Episode Mania Study [6–8], Baethge et al. [9•] examined the clinical characteristics of 112 patients who met the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria for bipolar type I disorder. The patients were followed for up to 2 years after their initial presenta- tion to McLean hospital with a manic or mixed episode. Thirty-seven (33%) of the patients were found to have a SUD at index, with 22 patients using only one substance. Alcohol abuse and dependence were the most common SUDs, followed by cannabis and then cocaine use disorders. Anxiety disorders were also found to be more frequent in patients with a SUD (30% vs 13%). Of the 80 patients who remained in the study 24 months after the initial diagnosis, 31 (39%) had a current SUD.