i3S study suggests link between psychopathic traits and gut and oral bacteria
A team of i3S scientists has identified associations between bacteria present in the gut and mouth and psychopathic traits in a sample from the general population. The research was published in the scientific journal Translational Psychiatry.
Psychopathy encompasses a range of characteristics, including impulsivity, manipulation, lack of empathy and antisocial behaviour. Although its origins involve both genetic and environmental factors, the biological mechanisms underlying these traits remain poorly understood.
In this study, the researchers recruited 200 Portuguese participants and assessed psychopathic traits, empathy and anxiety using psychological assessment scales. At the same time, they collected stool, saliva and blood samples to analyse the bacteria present in the body and identify chemical substances potentially involved in communication between the gut and the brain.
“The results show that certain gut and oral bacteria are associated with psychopathic traits in the community, suggesting that microorganisms in the body may be linked to processes involved in emotions and social behaviour,” explains Carolina Costa, the study’s first author, whose research was carried out as part of her PhD in Biomedical Sciences at the Abel Salazar Institute of Biomedical Sciences (ICBAS).
Among the main findings, the team identified associations between psychopathic traits and several specific gut bacteria. The researchers also observed differences in substances found in stool samples, namely glucose (sugar) and taurine, a molecule produced by the body that plays a role in several brain and metabolic functions. Both were associated with higher levels of the traits under study.
Despite these associations, the authors emphasise that the study does not demonstrate a cause-and-effect relationship.
“We cannot say that bacteria cause psychopathic traits, but we observed a relationship between certain oral and gut bacterial profiles and specific behavioural characteristics,” notes Benedita Sampaio-Maia, the study coordinator and researcher at i3S.
According to the researchers, these findings add to the growing body of evidence suggesting a connection between microorganisms in the gut and oral cavity and brain function, with potential effects on emotions and behaviour.
The work may pave the way for the future identification of biological markers associated with mental health, as well as the development of new intervention strategies based on diet, probiotics or other approaches aimed at modifying the body’s microbial communities.
The study was carried out in collaboration with researchers from the Faculty of Psychology and Educational Sciences of the University of Porto (FPCEUP), the Faculty of Dental Medicine of the University of Porto (FMDUP), and the University of Oxford.
