Examining the association between inflammation and motivational anhedonia in neuropsychiatric disorders: A systematic review.

Background Inflammation, motivational anhedonia, and neuropsychiatric disorders are associated with significant functional impairment and are a major public health concern. The objective of this systematic review is to examine the relationship between inflammatory activity and motivational anhedonia in neuropsychiatric disorders. Methods Preclinical and clinical studies were qualitatively synthesized and summarized. Results We found an association between inflammation and neuropsychiatric disorders, and a transdiagnostic association between motivational anhedonia and neuropsychiatric disorders. This review also identified brain regions associated with motivational processes that might have a latent vulnerability to persistent inflammatory activity. Motivational processes might be impacted early in the development of neuropsychiatric disorders, and could lead to a precursory manifestation of motivational anhedonia before (eg, prodromal phase) or early in the clinical course of the disorder. Conclusions Although inflammation, motivational anhedonia, and neuro psychiatric disorders are strongly associated, direct evidence of causal interactions are limited. Further research is required to understand the association and mechanical underpinnings, and improve assessment of this construct. The immune system could serve as a novel treatment target to improve symptoms of motivational anhedonia across diverse neuro psychiatric disorders; however, well-designed interventional studies are required to assess this hypothesis.