Glucagon-like Peptide-1 Receptor Agonists as a Dual-target Strategy for Depression and Metabolic Health: A Narrative...

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), originally developed for type 2 diabetes mellitus (T2DM) and obesity, show promising potential as a novel treatment for depression, particularly in patients with comorbid metabolic disorders. This narrative review examines the bidirectional relationship between obesity and depression, driven by shared mechanisms such as chronic low-grade inflammation, hypothalamic-pituitary-adrenal axis dysregulation, and impaired neuroplasticity. GLP-1 RAs, including liraglutide and exenatide, demonstrate neuroprotective effects by enhancing brain-derived neurotrophic factor expression and synaptic plasticity, alongside anti-inflammatory properties that reduce proinflammatory cytokines (e.g., tumor necrosis factor-alpha and interleukin-6). They also modulate serotonin turnover in mood-regulating brain regions, mirroring selective serotonin reuptake inhibitors. Preclinical studies in animal models reveal improved behavioral outcomes, while human observational studies and limited clinical trials, such as the LEAD-3 trial, report enhanced mood and quality of life in T2DM and obesity patients. However, challenges, including high treatment costs ($800-$1000/month), injectable administration, and needle-related anxiety, limit patient adherence, and clinical adoption. The lack of large-scale randomized controlled trials targeting depression as a primary outcome further hinders definitive conclusions. This review highlights GLP-1 RAs' potential to address both metabolic and depressive symptoms, offering a holistic approach to managing these interconnected conditions. Future research should focus on long-term efficacy, optimal dosing, and overcoming adherence barriers to establish GLP-1 RAs as a viable psychiatric treatment.