The impact of anhedonia on physical health and somatic diseases: an exploratory literature review.

Anhedonia, or the lack of interest and pleasure, is a transdiagnostic feature of mental health disorders with emerging links to physical health. This exploratory literature review investigated evidence of anhedonia's association with physical health and somatic diseases. A citation chaining approach was applied to 20 papers identified through targeted searches conducted from September to October 2024 on PubMed and Google/Google Scholar. Studies published in English and reporting outcomes in adults with anhedonia were included. Quality assessments were performed using the Centre for Evidence-Based Medicine critical appraisal tool for prognostic studies. Data on study characteristics, assessment and definition of anhedonia, and clinical outcomes were extracted. 41 publications on 40 unique studies were included. Most studies included patients with cardiac conditions, and 14 reported a psychiatric diagnosis, predominantly depression. Anhedonia was significantly associated with all-cause mortality, risk of major adverse cardiovascular events and worse physical health-related quality of life. Moreover, high positive affect was correlated with lower risk of functional decline, reduced inflammatory biomarkers and protective effects against conditions like diabetes and hypertension, compared with low positive affect. To our knowledge, this is the first exploratory review to gather evidence that anhedonia, whether occurring as a symptom of depression, another psychiatric disorder, or a somatic condition, may be associated with poorer health and somatic disease outcomes. Conversely, positive affect may confer protective benefits. These insights emphasise the need to prioritise development of treatment modalities that have proven impacts on hedonic tone.