The microbiota-gut-brain axis in neuropsychiatric disorders: Mechanisms, advances, and clinical applications.

Neuropsychiatric disorders are increasingly recognized as systemic conditions arising from dynamic interactions within the gut-brain-immune network. The Microbiota-Gut-Brain Axis (MGBA) serves as a central regulatory system orchestrating neurodevelopment, neural homeostasis, and immune-metabolic balance. This review summarizes evidence across seven major neuropsychiatric disorders, Depression, Autism Spectrum Disorder, Attention-Deficit/Hyperactivity Disorder, Alzheimer's disease, Schizophrenia, Anxiety and Obsessive Compulsive Disorder, demonstrating that dysregulation of the MGBA constitutes a shared pathological mechanism. On this common basis, we delineate disorder specific neurochemical and immunological features and highlight the clinical potential of microbiota-targeted interventions. Moreover, psychotropic medications profoundly alter microbial physiology, influencing bacterial growth and metabolism, thereby complicating interpretation of MGBA-disease relationships. Future research should define strain-specific therapeutic actions and integrate multi-omics approaches to unravel causal pathways, ultimately enabling precision microbiome modulation in neuropsychiatric medicine.