Psychobiotics in pediatric autism spectrum disorder: A systematic review of efficacy, mechanisms, and clinical translation

Figure 1 Psychobiotics and the gut-brain axis in autism spectrum disorder. Psychobiotics, including probiotics, prebiotics, synbiotics, and postbiotics, may modulate the gut microbiota by increasing beneficial bacteria, enhancing short-chain fatty acid production, and improving intestinal barrier integrity. These changes can influence the gut-brain axis through immune signaling, microbial metabolites, vagal pathways, and regulation of neuroactive compounds such as serotonin, gamma-aminobutyric acid, and dopamine. Through these interconnected mechanisms, psychobiotics may reduce gut inflammation, improve gastrointestinal function, and potentially influence neuroinflammation, neurotransmission, and behavioral outcomes associated with autism spectrum disorder. ASD: Autism spectrum disorder; GABA: Gamma-aminobutyric acid; HPA: Hypothalamic-pituitary-adrenal axis; SCFAs: Short-chain fatty acids.