Review articleMedical comorbidity in bipolar disorder: The link with metabolic-inflammatory systems

- BD has been consistently associated with inflammation-related general medical comorbidity.
- Several factors are involved in immune-inflammatory changes in BD including genetic factors, psychological stress and substance abuse.
- Iatrogenic effects of medication could induce and aggravate metabolic abnormalities in BD.
- Metabolically neutral medications and simultaneous treatment of BD and GMC are potentially useful alternatives to manage immuno-inflammatory changes.

BackgroundBipolar disorder (BD) is associated with chronic low-grade inflammation, several medical comorbidities and a decreased life expectancy. Metabolic-inflammatory changes have been postulated as one of the main links between BD and medical comorbidity, although there are few studies exploring possible mechanisms underlying this relationship. Therefore, the aims of the current narrative review were 1) synthesize the evidence for metabolic-inflammatory changes that may facilitate the link between medical comorbidity and BD and 2) discuss therapeutic and preventive implications of these pathways.MethodsThe PubMed and Google Scholar databases were searched for relevant studies.ResultsIdentified studies suggested that there is an increased risk of medical comorbidities, such as autoimmune disorders, obesity, diabetes and cardiovascular disease in patients with BD. The association between BD and general medical comorbidities seems to be bidirectional and potentially mediated by immune dysfunction. Targeting the metabolic-inflammatory-mood pathway may potential yield improved outcomes in BD; however, further study is needed to determine which specific interventions may be beneficial.LimitationsThe majority of identified studies had cross-sectional designs, small sample sizes and limited measurements of inflammation.ConclusionsTreatment and prevention of general medical comorbidities in mood disorders should include preferential prescribing of metabolically neutral agents and adjunctive lifestyle modifications including increased physical activity, improved diet and decreased substance abuse. In addition, the use of anti-inflammatory agents could be a relevant therapeutic target in future research.