In the general population, personality traits may predict the composition and diversity of the gut microbiome, a study published in the Human Microbiome Journal suggests.

At-home fecal samples from 655 adults were analyzed. Gut microbiota were sequenced and analyzed. Each participant also completed an online questionnaire with 44 continuous and categorical variables that assessed behavioral traits, diet, health, lifestyle, and sociodemographics.

Personality traits were assessed using the 50-item International Personality Item Pool, which divided participants into 5 key personality domains. These domains were extraversion, agreeableness, conscientiousness, neuroticism, and openness. Social skills and communication, social network size, dietary habits, and participants’ tendency to feel anxious were also assessed.

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The sociability personality trait positively predicted genus abundance for Akkermansia (P =.038), Lactococcus (P =.002), and Oscillospira (P <.001). In addition, sociability was a negative predictor of the abundances of Desulfovibrio (P =.019) and Sutterella (P =.028). Neurotic tendencies, consisting of a combination measure of neuroticism, anxiety, and stress, represented a negative predictor of a genus abundance for Corynebacterium (P <.001) and Streptococcus (P =.029).

Variables negatively correlated to the Shannon’s diversity index, a measure of gut microbiome diversity, included stress (Padj =.045), anxiety (Padj =.077), and agreeableness (Padj =.048). A positive correlation between the Shannon’s diversity index and social network size (Padj =.043) suggested that people with larger social networks more often have a greater diversity in the gut microbiome. People who ate more so-called adventurous foods, or foods that contained naturally occurring probiotics or prebiotics, also tended to have greater microbiome diversity.

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Limitations of this study included the small sample size and its cross-sectional nature, which precluded the ability to identify causation.

Findings from this and similar studies “may inform the development of probiotic or prebiotic therapies to help improve mood and treat conditions such as autism, anxiety and depression,” the study author wrote.


Johnson KVA. Gut microbiome composition and diversity are related to human personality traits. Human Microbiome Journal. 2020;15:100069.