Attempted suicide in people with co-occurring bipolar and substance use disorders: Systematic review and meta-analysis

BACKGROUND: Both individuals with bipolar (BD) and those with alcohol (AUD) and other substance (SUD) use disorders are likely to attempt suicide. Comorbidity of BD and AUD/SUD may increase the likelihood of suicide attempts. We conducted a meta-analysis to estimate the association of comorbid AUD/SUD and suicide attempts in subjects with BD in the literature to date. METHODS: Electronic databases through January 2013 were searched. Studies reporting rates of suicide attempts in people with co-occurring BD and AUD/SUD were retrieved. Comorbid AUD and SUD and suicide attempts rates as well as demographic, clinical, and methodological variables were extracted from each publication or obtained directly from its authors. RESULTS: Twenty-nine of 222 studies assessed for eligibility met the inclusion criteria, comprising a total of 31,294 individuals with BD, of whom 6308 (20.1%) had documented suicide attempts. There were consistent findings across the studies included. As compared to controls, subjects with BD and comorbid AUD/SUD were more likely to attempt suicide. The cross-sectional association estimates showed random-effects pooled crude ORs of 1.96 (95% CI=1.56-2.47; p<0.01), 1.72 (95% CI=1.52-1.95; p<0.01), and 1.77 (95% CI=1.49-2.10; p<0.01), for combined AUD/SUD, AUD, and SUD. There was no publication bias and sensitivity analyses based on the highest quality studies confirmed core results. LIMITATIONS: The effects of the number and the type of suicide attempts could not be investigated due to insufficient information. CONCLUSIONS: Comorbid AUD and SUD in individuals with BD are significantly associated with suicide attempts. Individuals with this comorbidity should be targeted for intensive suicide prevention efforts.