The five-factor model is a framework used to describe universal personality dimensions, which encompass five fundamental traits known as OCEAN: openness, conscientiousness, extraversion, agreeableness, and neuroticism. Research indicates that roughly half of our personality is inherited, while the remainder is shaped by social and environmental factors. The Big Five test is freely accessible at

Of these traits, neuroticism is particularly associated with psychological vulnerability and an increased susceptibility to health-related problems. A recent study conducted during the COVID-19 pandemic revealed that while neuroticism is linked to anxiety and depression, metacognitive strategies play a more substantial role in promoting emotional well-being. In this article, we explore a different approach to influencing neuroticism and managing mental health concerns by considering 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 examined 672 adults, ranging from 23 to 69 years old, and identified noteworthy variations in the diversity and composition of the gut microbiome based on the Big Five personality traits. Those who scored higher in neuroticism exhibited elevated levels of the bacterial class gammaproteobacteria, which includes potential pathogens. Similar increases were observed in individuals with lower scores in conscientiousness, a trait associated with motivation and self-discipline. The study also detected signs of HPA axis activation and heightened inflammatory markers in these individuals. Furthermore, the study suggested that increased gut barrier permeability and the presence of bacterial toxins might play a role in the physiology of neuroticism.

Another study in the Human Microbiome Journal delved into how gut microbes could impact personality traits through various pathways, including neural, immune, endocrine, and neurotransmitter systems. This study involved 655 adults, with an average age of 42 (83 percent from North America). It found that higher levels of anxiety and stress, as well as reduced sleep quality, were linked to changes in microbiome composition and reduced diversity. Specific bacterial genera were associated with distinct behavioral traits, such as certain Bacteroides strains linked to the production of the neurotransmitter GABA, which is crucial for managing stress and depression. Additionally, the study highlighted associations between the prevalence of particular gut bacteria and sociability or neuroticism levels.

The study did not uncover strong correlations between common probiotic species or strains and personality traits, emphasizing the strain-specific nature of these bacteria’s effects on behavior. Interestingly, although the study revealed a positive connection between mental well-being and diets rich in probiotic and prebiotic foods, it did not find a similar link among individuals taking probiotic supplements.

Nurturing the Gut to Nourish the Mind

The absence of significant correlations with supplemental probiotics may be attributed to the likelihood that individuals with lower gut diversity and more significant disturbances are more inclined to use supplements. The author suggests that the effectiveness of probiotics depends on strain-specific mechanisms. While maintaining a diverse and healthy gut is best achieved through a diet rich in probiotic and prebiotic foods, it can be helpful to carefully select high-performance probiotic formulations. Some of these formulations, known as psychobiotics, have demonstrated clinical effectiveness in enhancing mood, memory, cognition, and potentially influencing the Big Five personality traits positively. However, it is crucial to opt for probiotics supported by human clinical evidence for the final formulation, rather than relying solely on individual strains, to increase the likelihood of achieving the desired outcomes.

Categories: Health

Nicolas Desjardins

Hello everyone, I am the main writer for SIND Canada. I've been writing articles for more than 12 years and I like sharing my knowledge. I'm currently writing for many websites and newspapers. I always keep myself very informed to give you the best information. All my years as a computer scientist made me become an incredible researcher. You can contact me on our forum or by email at [email protected].