In one of the first studies of its kind, scientists have claimed that the organisms living inside the gut of psychopaths may be the drivers of their peculiar behaviour. The research team has claimed that they have discovered a link between the specific balance of microflora in the gut and psychopathic behaviour.As detailed in the yet-to-be-peer-reviewed study published in Translational Psychiatry, a team of researchers led by University of Porto biomedical scientist Carolina Costa said they’ve found the first-ever evidence of how microbiota could influence traits linked to psychopathy. Psychopathy is considered a controversial personality construct characterised by lack of empathy, poor behaviour control as well as antisocial and in extreme cases, criminal behaviour. It is important to understand that having some psychopathic traits does not automatically mean that a person is violent or criminal.As Science Alert points out, previous research has found that psychopaths can share similar brain structures, including pathways in the prefrontal cortex. The latest paper, however, suggests those links could even extend into the microbiome.
A gut connection?
The gut is home to trillions of microorganisms that help digest food, support immunity and produce chemicals that can affect the body. In recent years, scientists have become interested in the gut-brain axis, the two-way communication system that links the digestive system and the brain. This has eventually raised questions about whether the bacteria living inside our gut could influence mood, emotions and even behaviour.The researchers in this study were interested in subclinical psychopathic traits, meaning traits that can exist to different degrees in the general population rather than necessarily representing a clinical diagnosis. Their goal was to investigate whether the composition of gut and mouth bacteria was linked with these personality characteristics.“We hypothesised that the composition of the gut and oral microbiota may be associated with subclinical psychopathic personality traits,” the researchers wrote in the paper, an “unedited version” of which was shared by the journal Translational Psychiatry. “To our knowledge, this is the first study to explore this association.”Costa and her colleagues examined the answers of 200 adult participants who filled out a questionnaire that was specifically designed to measure psychopathic traits. They also analysed blood, saliva, and faecal samples from the participants for bacterial composition.While the diversity of gut and oral microbes showed no clear links to psychopathic traits in itself, those who showed stronger psychopathic traits had a higher abundance of three kinds of bacteria when compared to those with weaker psychopathic traits.“Allisonella, Prevotella, and C. evryensis showed significant positive associations with psychopathy scores, while T. vincentii was negatively associated,” the researchers concluded. The roles of these microbacteria range from helping in digestion and other metabolic processes, to assisting in warding off infections.The team suggested that Allisonella, in particular, has been linked to human diseases and has been found to promote inflammation, a “key factor in psychiatric disorders such as anxiety and depression,” thereby suggesting a “possible link to psychopathy.”Prevotella has also been linked to “differences in brain regions responsible for emotional, attentional and sensory processing, leading to a deficit in specificity of encoding contextual details of incoming stimuli.”The study also identified differences in certain substances produced or influenced by the body’s metabolism. Faecal levels of glucose and taurine differed between the groups and were positively associated with psychopathy scores. These findings could provide clues about possible biological pathways connecting the gut and the brain.
A controversial research
The claims from the research are positively controversial. For one, the sample size was on the smaller side and relied on self-reported findings, which could greatly skew results as they’re susceptible to bias. Results could also vary depending on geographic regions, the researchers point out.“Finally, as findings are correlational, causality cannot be established, especially given the bidirectionality of microbiota-brain communication,” they concluded.In other words, it may actually be an inverse relationship, with the balance of the gut microbiome being caused by psychopathic traits instead of the other way around.“For instance, psychopathy-linked factors, such as eating behaviours and hormonal differences could be responsible for shaping gut microbiota composition,” the researchers wrote.While this is a fascinating research, more investigation needs to be done to make a connection and statement thoroughly.