The Effect of Probiotic Supplementation in Alleviating Symptoms of Five Major Mental Illnesses: A Comprehensive Review

Abstract

Context: The gut microbiota significantly influences the formation and functioning of the brain due to its connection to the central nervous system via the gut-brain axis. This communication influences both physiological and psychological processes. Probiotic supplementation, which aims to restore and maintain a healthy gut microbiome, has emerged as a promising adjunctive treatment for various mental illnesses. Evidence Acquisition: This study serves as a comprehensive review of the relationship between gut microbiota and mental health disorders such as depression, bipolar disorder, schizophrenia, autism, and attention deficit hyperactivity disorder (ADHD). Additionally, it explores the effects of probiotic supplements on improving or mitigating the pathogenesis of these disorders. PubMed, Google Scholar, and Web of Science were searched for relevant studies published up to November 2024. Results: The findings support alterations in the gut microbiome among individuals with mental health disorders, including depression, schizophrenia, ADHD, and autism, which contribute to pathogenesis associated with these conditions. Regarding probiotics’ impact on mental health disorders, evidence indicates that the Lactobacillus and Bifidobacterium families may play a role in alleviating clinical symptoms and improving general mental health in individuals with neurodevelopmental disorders. Probiotics also contribute significantly to regulating the gut microbiome and decreasing epithelial barrier permeability. Conclusions: The evidence gathered suggests that probiotics positively influence therapeutic processes for individuals with these diseases; however, further studies are required to understand how probiotics affect the gut-brain axis mechanisms.