Medical Comorbidities in Bipolar Disorder

Bipolar disorder (BD) medical comorbidity presents significant clinical and public health concerns with serious impact on health. The aim of this article is to present an updated narrative review of original research articles (case control, longitudinal cohort, and cross-sectional studies) and meta-analyses published in English language journals from January 2013 to May 2017 focusing on general medical comorbidity in BD, including the added risks of iatrogenic factors relevant to the treatment of BD. We found numerous patterns of association between BD and various medical disorders involving multiple organ systems. One pattern indicated reciprocal increase in the rate of each comorbid condition, such as an increased rate of BD in asthma or migraine, and likewise an increase in the rate of asthma or migraine in patients with BD. A second pattern was a predominantly unidirectional increase in the rate of BD in patients with certain medical disorders, such as multiple sclerosis or cerebellar diseases. A third pattern was a predominantly unidirectional increased rate of medical disorders in patients with BD. One study suggested the potential involvement of genetic mechanisms for the association between BD and migraine. Most of the studies had cross-sectional or retrospective designs, and many relied on analysis of large administrative databases inviting multiple potential biases. Our review highlights the association between BD and a variety of medical disorders. Further research is needed to elucidate the potential underlying etiopathological mechanisms that contribute to observed comorbidities. The results of this review also emphasize the need for comprehensive screening for medical disorders in BD and for adoption of an integrated model of care to address these complex comorbidities.