According to a study published in Translational Psychiatry, scientists have discovered a link between specific gut bacteria and subclinical psychopathic traits in humans. Researchers led by University of Porto biomedical scientist Carolina Costa found that adults scoring higher on psychopathic personality questionnaires exhibited a distinct abundance of certain microflora in their digestive tracts and mouths compared to those with lower scores.
The Gut-Brain Axis and Personality Traits
The human gut contains trillions of microorganisms responsible for aiding digestion, supporting immune functions, and producing chemicals that influence the body. Scientists increasingly study the gut-brain axis, a two-way communication pathway connecting the digestive system to the brain. This biological network raises questions about whether resident bacteria affect human moods, emotions, and behavior.
In this latest project, researchers focused on subclinical psychopathic traits. These characteristics exist to varying degrees across the general population rather than pointing strictly to a clinical diagnosis. The team sought to determine if mouth and gut bacteria compositions aligned with these distinct personality markers. According to the study, investigators hypothesized that microbiome compositions associate directly with subclinical psychopathic traits.
Did you know? The gut microbiome produces chemicals that can affect the body.
Specific Bacteria Linked to Psychopathy Scores
Researchers examined answers from 200 adult participants who completed a questionnaire designed to measure psychopathic traits. The team also analyzed blood, saliva, and faecal samples to map bacterial compositions. While overall microbial diversity showed no direct connection to psychopathy scores, participants with stronger traits displayed a higher abundance of three specific bacterial kinds.
According to the findings, Allisonella, Prevotella, and C. evryensis showed significant positive associations with higher psychopathy scores. Conversely, T. vincentii showed a negative association. The research team noted that Allisonella has previously linked to human diseases and promotes inflammation, a known key factor in psychiatric disorders like anxiety and depression. Furthermore, Prevotella connects to differences in brain regions responsible for emotional, attentional, and sensory processing.
Metabolic Byproducts and Biological Pathways
Beyond bacteria, the study identified variations in substances produced or influenced by human metabolism. Faecal levels of glucose and taurine differed noticeably between participant groups. These specific chemical levels showed positive associations with psychopathy scores, offering potential clues about the biological pathways connecting the digestive tract to the brain.
However, the research remains controversial due to several methodological limitations. The sample size was relatively small and relied heavily on self-reported questionnaire findings, which remain susceptible to personal bias. Results can also vary significantly depending on geographic regions. Because the findings are strictly correlational, researchers emphasized that causality cannot be established yet.
The gut-brain communication channel operates bidirectionally. This means an inverse relationship remains entirely possible, where psychopathic traits, unique eating behaviors, or hormonal differences shape the gut microbiome rather than bacteria driving the behavior.
Frequently Asked Questions
Does having gut bacteria linked to psychopathy mean a person is dangerous?
Having some psychopathic traits does not automatically mean that a person is violent or criminal.
Can we change our personality by changing our gut microbiome?
Not currently. Researchers emphasize that the study is correlational. Causality cannot be established, especially given the bidirectionality of microbiota-brain communication.
Was this study peer-reviewed?
The study was detailed in the yet-to-be-peer-reviewed study published in Translational Psychiatry.
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