Diagnostic validity of comorbid bipolar disorder and obsessive-compulsive disorder: a systematic review Amerio A, Odone A, Liapis CC, Ghaemi SN. 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, PsycINFO, 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 AE 4.2 vs. 4.1 AE 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. • The evidence so far on BD-OCD nosology-mainly based on the course of illness-supports the view that the majority of cases of comorbid BD-OCD are in fact cases of BD. OC symptoms usually are secondary manifestations of depressive or manic mood episodes.• BD-OCD patients may respond for both groups of symptoms with adequate doses of mood stabilizers and atypical antipsychotics. Because of the risk of worsening BD via SRI-induced mania/hypomania, antidepressants should only be used in a minority of refractory OCD.
Considerations• Course of illness is the only diagnostic validator that clearly supports the OCD-BD construct as a subtype of BD. Findings on the phenomenology, heredity, biological markers, and treatment were fragmented and heterogeneous and mainly suggested increased severity of illness or functioning without helping us to answer the nosological question.• The use of retrospective assessment scales with unclear sensitivity in discriminating true ego-dystonic obsessions from depressive ruminations may have biased results toward an overestimation of obsession's prevalence. In addition, small sample sizes, mainly from out-patients units, may have limited the generalizability of the results to a whole community.