Context: More than half of the bipolar disorder (BD) cases have an additional diagnosis; one of the most difficult to manage is obsessive-compulsive disorder (OCD). Although some authors recently investigated the co-occurrence of anxiety and BD, the topic remains insufficiently studied. The current study aimed to investigate differences in comorbid OCD between BD-I and BD-II.
Evidence acquisition: A systematic review and meta-analysis was conducted on the prevalence and predictors of comorbid BD-I/BD-II and OCD. Relevant papers published until June 30, 2015 were identified searching the electronic databases MEDLINE, Embase, PsycINFO and the Cochrane Library.
Results: Fourteen articles met the inclusion criteria. The pooled prevalence of BD-I in OCD was 3.9% (95% confidence interval (CI), 2.4 to 6.4, I2 = 83%, Q = 56) while that of BD-II in OCD was 13.5% (95% CI, 9.3 to 19.3, I2 = 89%, Q = 91). The pooled prevalence of OCD in BD-I was 21.7 (95% CI, 4.8 to 60.3, I2 = 84%, Q = 95). With regard to OCD-BD predictors, mean age and rate of males did not predict the prevalence of BD-I (β = 0.0731, 95% CI, -0.1097 to 0.256, z = 0.78; β = 0.035, 95% CI, -0.2356 to 0.1656, z = 0.34) and BD-II (β = 0.0577, 95% CI, -0.1942 to 0.0788, z = 0.83; β = -0.0317, 95% CI, -0.1483 to 0.085, z = 0.53) in OCD. The mean age explained some of the observed heterogeneity (R2 = 0.13; R2 = 0.08).
Conclusions: This first systematic review and meta-analysis of the prevalence and predictors of comorbid BD-I/BD-II and OCD suggests that BD-OCD comorbidity is a common condition in psychiatry. However, the available evidence does not allow to assess whether BD-I or BD-II are more common in patients with OCD.
Keywords: Bipolar I; Bipolar II; Obsessive-Compulsive: Comorbidity.