The Genetic Basis of Future Pharmacological Strategies for the Management of Comorbid Obesity and Depression: A Scoping Review

Depression and obesity are highly comorbid with one another, with evidence for bidirectional causal links between each disorder and a shared biological basis. The available evidence suggests that genetic factors play a major role in influencing both the occurrence of comorbid depression and obesity, their courses, and their response to existing treatments. The current paper is a scoping review of studies that have evaluated the contribution of specific genetic variants to the comorbidity between obesity and depression. Based on a search of the PubMed and EMBASE databases, 28 studies were included in this review, covering 54 candidate genes. Positive associations were identified for fourteen genetic loci (AKR1C2, APOA5, COMT, DAT1, FTO, KCNE1, MAOA, MC4R, MCHR2, NPY2R, NR3C1, Ob, PCSK9 and TAL1). Replicated findings across two or more independent samples were observed for the FTO and MC4R genes. Many of these gene products represent novel molecular targets for the pharmacological management of obesity which are not pharmacologically influenced by existing anti-obesity or antidepressant medications. The implications of these associations for future drug development are discussed, with an emphasis on recent evidence on the polygenic architecture of comorbid depression and obesity, and on a precision medicine approach to these conditions.