From Mouth to Mind: Oral Biome and Its Neuropsychiatric Effects— A Systematic Review

Aim: The oral microbiome is a complex community of microorganisms residing in the mouth, playing an essential role in oral, systemic, and neuropsychiatric health. The objective of this review is to examine the extent of neuropsychiatric disorders that are related to the oral microbiome, as well as to promote more research in this area. Methods: A comprehensive search was performed on Google Scholar, Web of Science, and PubMed following PRISMA guidelines, including studies published up to May 2025. All the English-language papers were evaluated based on the inclusion and exclusion criteria established. Results: A total of 15 studies met the inclusion criteria. Studies argue about the correlations between shifts in oral microbiome, which affect anxiety, stress, trauma, depression, bipolar affective disorder, panic disorder, autism spectrum disorder, and maternal stress and anxiety. Conclusion: The results indicate a noteworthy, albeit intricate, link between disruptions in the oral microbiome and neuropsychiatric health. Additional longitudinal and mechanistic research is needed to better understand the underlying pathways and guide clinical interventions.