Medically unexplained somatic symptoms and bipolar spectrum disorders: A systematic review and meta-analysis

Background: Patients with bipolar spectrum disorders (BSD) frequently report medically unexplained somatic symptoms. However, the prevalence and the consequences for treatment and outcome are currently unknown.

Methods: To estimate the prevalence of somatic symptoms in BSD, we conducted a systematic review and meta-analysis of empirical studies published between 1980 and 2015. The odds for somatic symptoms in BSD were compared with unipolar depression (UPD) and general population or mixed psychiatric controls. Studies were retrieved from four electronic databases utilizing Boolean operations and reference list searches. Pooled data estimates were derived using random-effects methods.

Results: Out of 2634 studies, 23 were eligible for inclusion, yielding an N of 106,785 patients. The estimated prevalence of somatic symptoms in BSD was 47.8%. The estimated prevalence of BSD in persons with somatic symptoms was 1.4%. Persons with BSD had a higher prevalence of somatic symptoms compared with population or mixed psychiatric controls (OR 1.82, 95% CI 1.14-2.92). Persons with BSD had a similar prevalence of somatic symptoms compared with UPD controls (OR 0.99, 95% CI 0.68-1.44).

Limitations: This study is correlational; thus causal inferences cannot be made. Reporting of somatic symptoms likely varies with BSD severity and subtype. Some studies reported insufficient information regarding comorbid medical conditions and medications.

Conclusions: Persons with BSD suffer from somatic symptoms at a rate nearly double that of the general population, a rate similar to persons with UPD. Our results suggest the utility of an integrated care model in which primary care and specialist physicians collaborate with mental health professionals to jointly address psychological and bodily symptoms.