Marked shifts in gut microbial structure and neurotransmitter metabolism in fresh inmates revealed a close link between gut microbiota and mental health: A case-controlled study

BACKGROUND/OBJECTIVE: The gut microbiota plays a pivotal role in psychological health, but the mechanistic perspective between gut microbiome and mental health remains poorly understood METHOD: The present case-controlled study recruited 30 unimprisoned subjects and 31 inmates that had been detained in jail for no more than a month. The mental health status, gut microbiota and blood NH3, H2S, 5-hydroxy trptamine and dopamine levels were measured. RESULTS: Compared with unimprisoned controls, the fresh inmates exhibited significantly higher scores on anxiety and depression. Both phylogenetic structure and functional genes of the gut microbiota markedly shifted in inmates. Inmates was more Bacteroides-dominated, while unimprisoned subjects were more Prevotella-dominated. Short-chain fatty acids (SCFAs)-producing genera were largely decreased in inmates and were negatively related to mental disorder scores, while Bacteroidetes and Proteobacteria were positive to anxiety and depression scores. Simultaneously, the inmates possessed reduced genes that participate in amino acids, carbohydrates and vitamin cofactors metabolism, but enriched genes that involved in the neurotransmitter-producing Shikimate pathway. Correlation analysis revealed that Anaerotruncus and Prevotella were negative to depression score, and Enterococcus was negative to anxiety score. CONCLUSIONS: Our results revealed potential link between gut microbiota and mental health, leading further support to the microbiota–gut–brain axis theory.