The Gut’s Impact on the Big Five Personality Traits

The five-factor model serves as a framework for delineating universal personality dimensions, encompassing five essential traits known as OCEAN: openness, conscientiousness, extraversion, agreeableness, and neuroticism. Research suggests that approximately half of our personality is inherited, while the remainder is molded by societal and environmental factors. The Big Five personality test can be taken for free on the Psyculator platform. 

Among these traits, neuroticism is particularly linked to psychological vulnerability and a heightened susceptibility to health-related issues. A recent study conducted during the COVID-19 pandemic disclosed that while neuroticism is associated with anxiety and depression, metacognitive strategies assume a more significant role in enhancing emotional well-being. In this article, we explore an alternative approach to influencing neuroticism and addressing mental health challenges by exploring the connection between the gut and the brain.

Personality and the Gut Microbiome

In a recent observational study published in Brain, Behavior, and Immunity, researchers scrutinized 672 adults, spanning ages from 23 to 69, and discerned notable variations in the diversity and composition of the gut microbiome linked to the Big Five personality traits. Individuals with higher neuroticism scores displayed heightened levels of the bacterial class gammaproteobacteria, which includes potential pathogens. Similar elevations were observed in individuals scoring lower in conscientiousness, a trait associated with motivation and self-discipline. The study also identified indications of HPA axis activation and elevated inflammatory markers in these individuals. Moreover, the study posited that increased gut barrier permeability and the presence of bacterial toxins might contribute to the underpinnings of neuroticism.

Another study in the Human Microbiome Journal probed into how gut microbes could impact personality traits through various avenues, encompassing neural, immune, endocrine, and neurotransmitter systems. This study encompassed 655 adults, with an average age of 42 (with 83 percent hailing from North America). It revealed that heightened anxiety and stress levels, coupled with diminished sleep quality, were correlated with alterations in microbiome composition and reduced diversity. Distinct bacterial genera were associated with specific behavioral traits, with particular Bacteroides strains linked to the production of the neurotransmitter GABA, pivotal in managing stress and depression. Furthermore, the study illuminated connections between the prevalence of specific gut bacteria and levels of sociability or neuroticism.

The study failed to unveil robust correlations between common probiotic species or strains and personality traits, underscoring the strain-specific nature of these bacteria’s effects on behavior. Intriguingly, even though the study established a positive relationship between mental well-being and diets rich in probiotic and prebiotic foods, no similar connection emerged among individuals taking probiotic supplements.

Cultivating the Gut to Nourish the Mind

The dearth of substantial correlations with supplemental probiotics might be ascribed to the probability that individuals with lower gut diversity and more pronounced disturbances are more inclined to resort to supplements. The author posits that the efficacy of probiotics hinges on strain-specific mechanisms. While sustaining a varied and healthy gut is most effectively achieved through a diet abundant in probiotic and prebiotic foods, it may be advantageous to selectively opt for high-performance probiotic formulations. Some of these formulations, recognized as psychobiotics, have showcased clinical efficacy in enhancing mood, memory, cognition, and potentially exerting positive influences on the Big Five personality traits. Nonetheless, it remains imperative to select probiotics substantiated by human clinical evidence for the final formulation, rather than solely relying on individual strains, to heighten the likelihood of attaining desired outcomes.