Most patients with both bipolar disorder and obsessive–compulsive disorder (OCD) should be treated as having bipolar disorder, researchers suggest.
In their systematic review of OCD and bipolar disorder comorbidity, they found that, in the majority of cases, OC symptoms are secondary manifestations of mood episodes rather than a separate disease.
This finding has important implications regarding the treatment of the condition, say the researchers, led by Andrea Amerio (University of Parma, Italy), given that antidepressant treatment of OCD can worsen bipolar disorder.
The researchers conducted a comprehensive literature review considering all aspects of OCD and bipolar disorder comorbidity. Research papers were considered if they included bipolar disorder and OCD patients over 6 years of age and without physical comorbidities, as long as the diagnostic criteria used were specified.
A total of 749 articles published up until 30 March 2013 were retrieved, of which 64 were included in the study.
Amerio et al found that lifetime prevalence of comorbid OCD was 11% to 21% in bipolar disorder patients and that of comorbid bipolar disorder was 6% to 10% in OCD patients. Restricting the analysis to studies with a sample size of greater than 250 resulted in a predicted comorbid OCD and bipolar disorder prevalence of 3.0% to 13.6%.
About 50–75% of OCD cases occurred only during mood episodes in bipolar disorder, according to the course of illness studies, suggesting that they were secondary to mood episodes. However, “a substantial minority of comorbid OCD cases are not episodic and may represent ‘true’ OCD independent of [bipolar disorder]”, the researchers write in Acta Psychiatrica Scandinavica.
In comparison with non-comorbid OCD patients, those with bipolar disorder had a more episodic course of OC symptoms (up to 75 vs 3%), which typically worsened during depression (78%) and improved during mania/hypomania (64%).
They also had poorer functioning and quality of life compared with patients with only one diagnosis, and five studies also reported higher hospitalisation rates in comorbid patients.
The researchers note that comorbidity was associated with a higher total mean number of depressive episodes (8.9 vs 4.1) and possibly more antidepressant-induced mania/hypomania (39 vs 9%).
This led them to conclude that “[bipolar disorder]–OCD patients may respond for both groups of symptoms with adequate doses of mood stabilizers and atypical antipsychotics. Because of the risk of worsening [bipolar disorder] via [serotonin reuptake inhibitor-induced mania/hypomania, antidepressants should only be used in a minority of refractory OCD”.
