Metabolic Dysfunction in Psychiatric Disorders: A Narrative Review of Shared Pathways Between Mental Illness and Cardiometabolic Disease

Psychiatric disorders and cardiometabolic disease (CMD) frequently coexist and contribute to substantial morbidity, premature mortality, and reduced quality of life. Although this association is increasingly recognized, the shared biological and clinical pathways linking mental illness with metabolic dysfunction remain incompletely defined. This article is a narrative review that examines recent evidence on mechanisms connecting depression, anxiety, schizophrenia, severe mental illness (SMI), obesity, insulin resistance, diabetes, dyslipidemia, hypertension, and cardiovascular disease. A narrative review approach was used, with literature identified from major biomedical databases and prioritized according to relevance to shared psychiatric-metabolic mechanisms, clinical significance, recency, and methodological strength. The review focuses on chronic low-grade inflammation, hypothalamic-pituitary-adrenal (HPA) axis dysregulation, insulin resistance, oxidative stress, mitochondrial dysfunction, altered brain energy metabolism, gut microbiome disruption, sleep and circadian disturbance, psychotropic medication effects, and behavioral and social determinants. Current evidence suggests that psychiatric and cardiometabolic disorders are associated through bidirectional and overlapping pathways rather than a single causal mechanism. Metabolic dysfunction may be associated with worsening psychiatric symptoms through inflammatory, neuroendocrine, and neurotrophic effects, while psychiatric illness may increase cardiometabolic risk (CMR) through stress biology, lifestyle factors, medication exposure, and fragmented healthcare access. Antipsychotic-associated weight gain and glucose-lipid abnormalities remain important, but metabolic changes may also precede long-term treatment exposure, particularly in psychotic disorders. These findings support routine metabolic screening, early risk stratification, individualized psychotropic prescribing, lifestyle intervention, and integrated care involving psychiatry, primary care, endocrinology, cardiology, nutrition, and behavioral health services. Future longitudinal studies and randomized trials are needed to clarify causality and evaluate interventions that improve both psychiatric and cardiometabolic outcomes. Metabolic health should be considered a core component of psychiatric assessment and management.