The Role of Gut Microbiota in the High-Risk Construct of Severe Mental Disorders: A Mini Review

Abstract

Severe mental disorders (SMD) are highly prevalent psychiatric conditions exerting an enormous toll on society. Therefore, prevention of SMD has received enormous attention in the last two decades. Preventative approaches are based on the knowledge and detailed characterization of the developmental stages of SMD and on risk prediction. One relevant biological component, so far neglected in high risk research, is microbiota. The human microbiota consists in the ensemble of microbes, including viruses, bacteria, and eukaryotes, that inhabit several ecological niches of the organism. Due to its demonstrated role in modulating illness and health, as well in influencing behavior, much interest has focused on the characterization of the microbiota inhabiting the gut. Several studies in animal models have shown the early modifications in the gut microbiota might impact on neurodevelopment and the onset of deficits in social behavior corresponding to distinct neurosignaling alterations. However, despite this evidence, only one study investigated the effect of altered microbiome and risk of developing mental disorders in humans, showing that individuals at risk for SMD had significantly different global microbiome composition than healthy controls. We then offer a developmental perspective and provided mechanistic insights on how changes in the microbiota could influence the risk of SMD. We suggest that the analysis of microbiota should be included in the comprehensive assessment generally performed in populations at high risk for SMD as it can inform predictive models and ultimately preventative strategies.

Involvement of Gut Microbiota in Schizophrenia and Treatment Resistance to Antipsychotics

“…This could permit to ascertain whether changes in the composition of the gut microbiota correspond to major psychopathological modifications, establishing causality. While the analysis of drug-naïve patients would be particularly difficult in the case of TRS, given that this tends to be a mid/long term outcome in the clinical course of SCZ, and patients with TRS have, by definition, been exposed to several trials of antipsychotics, such an approach could be feasible only using establishing prospective cohorts followed in the long-term, as for high-risk studies [ 53 , 54 ]. Finally, translational approaches, including those using faecal transplant of the gut microbiota from more severe SCZ cases, such as TRS, into germ free animals, could lead to the identification of specific phenotypic alterations in animal models, and eventually of biosignature which can be reverse translated and validated in humans.…”

Protein Intake and Cognitive Function in Older Adults: A Systematic Review and Meta-Analysis

“… 75 Besides, cross-sectional studies using nationally representative samples have observed that people with sleep disturbance had a low protein intake. 35 , 36 More recently, the role of microbiota on cognitive impairment 76 and severe mental disorders 77 has received increased attention. These data have important clinical implications since protein intake and microbiota are interconnected so that the structure and function of the microbiome might be impacted by protein quality, while it influences protein catabolism, digestion, and absorption.…”

Definition of a Dietary Pattern Expressing the Intake of Vegetables and Fruits and Its Association with Intestinal Microbiota

“…In this index, greater distance indicates the greater difference between samples in the intestinal microbiota. In evaluations of the diversity of intestinal microbiota and various diseases, it was reported that many disease patients, for instance, lifestyle-related diseases, inflammatory diseases, mental disorders and infections, had a decreased α-diversity compared to healthy individuals [27][28][29][30][31][32][33][34][35][36], suggesting that the richness and evenness of intestinal microbiota have important roles on not only specific diseases but also general health conditions. This is likely because a decrease in α-diversity of intestinal microbiota causes a decline in the complementary/alternative functions of intestinal bacteria, making hosts vulnerable to changes in the external environment and susceptible to diseases [1].…”