Diagnostic validity of comorbid bipolar disorder and obsessive–compulsive disorder: a systematic review

Objective At least 50% of bipolar disorder ( BD ) patients have an additional diagnosis, one of the most difficult to manage being obsessive–compulsive disorder ( OCD ). Defining the nosology of BD ‐ OCD comorbidity has important clinical implications, given that treatments for OCD can worsen BD outcomes. Method A systematic review was conducted on: i) BD ‐ OCD comorbidity lifetime prevalence and ii) on standard diagnostic validators: phenomenology, course of illness, heredity, biological markers, and treatment response. Relevant papers published through March 30th 2013 were identified searching the electronic databases MEDLINE , Embase, Psyc INFO , and the Cochrane Library. Results Sixty‐four articles met inclusion criteria. Lifetime comorbidity prevalence was 11–21% in BD patients and 6–10% in OCD patients. Compared to non‐comorbid subjects, BD ‐ OCD has a more episodic course of OC symptoms (up to 75% vs. 3%), typically with worsening during depression (78%) and improvement during mania/hypomania (64%), as well as a higher total mean number of depressive episodes (8.9 ± 4.2 vs. 4.1 ± 2.7) and perhaps more antidepressant‐induced mania/hypomania (39% vs. 9%). Conclusion In this first systematic review of BD ‐ OCD comorbidity, it appears that OC symptoms are usually secondary to BD , rather than representing a separate disease.