Bipolar I and II Disorders; A Systematic Review and Meta-Analysis on Differences in Comorbid Obsessive-Compulsive Disorder.
BACKGROUND
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.


METHODS
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.
Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy; Mood Disorders Program, Tufts Medical Center, Boston, MA, USA.
Andrea
A
Amerio
Institute of Psychiatry, Kings College London, London, UK.
Brendon
B
Stubbs
School of Medicine-Public Health Unit, University of Parma, Parma, Italy; Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, USA.
Anna
A
Odone
Department of Mental Health, Local Health Service, Parma, Italy.
Matteo
M
Tonna
Department of Mental Health, Local Health Service, Parma, Italy.
Carlo
C
Marchesi
Mood Disorders Program, Tufts Medical Center, Boston, MA, USA; Tufts University Medical School, Department of Psychiatry and Pharmacology, Boston, MA, USA.
S
S
Nassir Ghaemi
Bipolar I; Bipolar II; Obsessive-Compulsive: Comorbidity