Scientists say organisms living inside the intestines of psychiatric patients can be drivers of bad and sinful behavior

In one of the first studies of its kind, scientists have claimed that organisms living inside the gut of psychiatric patients may be the driver of their strange behaviour. The research team claimed to have discovered a link between the specific balance of bacteria in the gut and psychopathic behaviour.As detailed in the not-yet-peer-reviewed study published in the journal Translational Psychiatry, a team of researchers led by University of Puerto Carolina biomedical scientist Costa said they have found the first-ever evidence of how microorganisms influence traits associated with psychopathy. Psychopathy is a controversial personality construct characterized by lack of empathy and poor behavioral control as well as antisocial and, in extreme cases, criminal behavior. It is important to understand that having certain psychopathic traits does not automatically mean that a person is violent or a criminal.As Science Alert noted, previous research has found that psychopaths could share similar brain structures, including pathways in the prefrontal cortex. However, the latest research suggests that these links could extend to the microbiome.

Gut connection?

The intestine 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 ultimately raised questions about whether the bacteria that live inside our gut can influence mood, emotions, and even behavior.The researchers in this study were interested in subclinical psychopathic traits, that is, traits that can be present to varying degrees in the general population rather than necessarily representing a clinical diagnosis. Their goal was to investigate whether the composition of gut and oral bacteria was related to these personality characteristics.“We hypothesized 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 in 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 specifically designed to measure psychopathic traits. They also analyzed blood, saliva and stool samples from the participants for bacterial composition.While the diversity of gut and oral microbes did not show any clear links to psychopathic traits per se, those who showed stronger psychopathic traits had higher abundances of three types of bacteria 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 tiny bacteria range from aiding in digestion and other metabolic processes, to helping ward off infection.Alisonella, in particular, has been linked to human disease and has been found to promote inflammation, a “key factor in psychiatric disorders such as anxiety and depression,” suggesting a “potential link to psychopathy,” the team suggested.Prevotella has also been linked to “differences in brain regions responsible for emotional, attentional, and sensory processing, leading to deficits in the specificity of encoding contextual details of incoming stimuli.”The study also identified differences in some substances that are produced or affected by the body’s metabolism. Stool glucose and taurine levels differed between the two groups and were positively associated with psychopathy scores. These findings could provide clues about potential biological pathways linking the gut and brain.

Controversial research

The claims from the research are positively controversial. First, the sample size was smaller and relied on self-reported outcomes, which can significantly skew the results because they are subject to bias. The researchers point out that results may also vary depending on geographic regions.“Finally, because the results are correlational, causality cannot be proven, especially given the bidirectionality of communication between the microbiota and the brain,” the researchers concluded.In other words, it may actually be an inverse relationship, where gut microbiome balance is a result of psychopathic traits rather than the other way around.“For example, factors associated with psychopathy, such as eating behaviors and hormonal differences, could be responsible for shaping the composition of the gut microbiota,” the researchers wrote.While this is fascinating research, more investigation needs to be done to make a comprehensive connection and statement.