The Microbiome in Posttraumatic Stress Disorder and Trauma-Exposed Controls: An Exploratory Study
Inadequate immunoregulation and elevated inflammation may be risk factors for posttraumatic stress disorder (PTSD), and microbial inputs are important determinants of immunoregulation; however, the association between the gut microbiota and PTSD is unknown. This study investigated the gut microbiome in a South African sample of PTSD-affected individuals and trauma-exposed (TE) controls, to identify potential differences in microbial diversity or microbial community structure.Methods
The Clinician Administered Posttraumatic Stress Disorder Scale for DSM-5 (CAPS-5) was used to diagnose PTSD according to DSM-5 criteria. Microbial DNA was extracted from stool samples obtained from 18 individuals with PTSD and 12 TE control participants. Bacterial 16S ribosomal RNA (rRNA) gene V3/V4 amplicons were generated and sequenced. Microbial community structure, alpha-diversity, and beta-diversity were analyzed; random forest analysis was used to identify associations between bacterial taxa and PTSD.Results
There were no differences between PTSD and TE control groups in alpha- or beta-diversity measures (e.g., alpha-diversity, Shannon index, t = 0.386, P = .70; beta diversity, based on analysis of similarities (ANOSIM), Bray Curtis test statistic = –0.033, P = .70); however, random forests analysis highlighted three phyla as important to distinguish PTSD status: Actinobacteria, Lentisphaerae, and Verrucomicrobia. Decreased total abundance of these taxa was associated with higher PTSD CAPS scores (r = –.387, P = .035).Conclusions
In this exploratory study, measures of overall microbial diversity were similar among individuals with PTSD and TE controls; however, decreased total abundance of Actinobacteria, Lentisphaerae, and Verrucomicrobia was associated with PTSD status.