The Gut Microbiome in Psychosis From Mice to Men: A Systematic Review of Preclinical and Clinical Studies

Abstract

The gut microbiome is rapidly becoming the focus of interest as a possible factor involved in the pathophysiology of neuropsychiatric disorders. Recent understanding of the pathophysiology of schizophrenia emphasizes the role of systemic components, including immune/inflammatory and metabolic processes, which are influenced by and interacting with the gut microbiome. Here we systematically review the current literature on the gut microbiome in schizophrenia-spectrum disorders and in their animal models. We found that the gut microbiome is altered in psychosis compared to healthy controls. Furthermore, we identified potential factors related to psychosis, which may contribute to the gut microbiome alterations. However, further research is needed to establish the disease-specificity and potential causal relationships between changes of the microbiome and disease pathophysiology. This can open up the possibility of. manipulating the gut microbiome for improved symptom control and for the development of novel therapeutic approaches in schizophrenia and related psychotic disorders.

Keywords: early life events; gut microbiota; inflammation; microbiota metabolites; schizophrenia; stress.

Figure 1

Flow diagram (47).

Figure 2

SYRCLE’s risk of bias tool.

Figure 3

Quality assessment of all animal studies.

Figure 4

STROBE completeness of reporting analysis of human studies.

Figure 5

Microbiome methodological consideration.

Figure 6

Taxonomic tree of schizophrenia. Showing reduced abundance in orange, increased abundance in purple with lighter shades of orange and purple to signify that only preclinical evidence is available. White-no change only for representative purposes. Ultrahigh-risk individuals †(4), first episode psychosis ^ (54), first episode schizophrenia “(55), chronic schizophrenia # (57) ∇(56) ∞(40), maternal immune activation model + (53), pharmacological model * (52), social isolation! (46).