How DNA shapes who we are: More than 1,200 genetic variants help determine personality

A massive genetic study has uncovered significant connections between an individual's DNA and their personality traits, according to a new research published in Nature. The extensive study, involving over 1.14 million participants across 46 research studies in 13 countries, sought to explore the role of genetics in shaping human personality.

The researchers utilized a method called genome-wide association studies (GWAS) to examine the DNA of a large number of individuals simultaneously, searching for common genetic variants linked to specific personality traits. The results revealed over 1,260 genetic markers associated with the Big Five personality traits, including extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience.

These traits, often referred to as the "Big Five," are now widely accepted by scientists as a more continuous and accurate way to describe personality compared to traditional personality type systems. The study found that between 5 and 16% of the variation in personality traits could be explained by common genetic variants, suggesting that genetics plays a substantial role in determining our personality traits.

Interestingly, the researchers discovered that the genetic markers associated with most personality traits were strongly linked to genes expressed in the prefrontal cortex, a brain region responsible for emotional regulation, decision-making, and self-control. This area is also implicated in various psychiatric disorders, such as anxiety, schizophrenia, ADHD, and bipolar disorder.

The findings imply that the genetics of personality shares substantial overlap with the genetics of psychiatric disorders, which may explain their consistent association with the same brain region. Moreover, the study revealed that certain personality traits, such as extraversion, can directly impact physical health. For instance, individuals who scored high in extraversion were found to have a higher risk of COVID-19 infection, while those with high conscientiousness had a lower BMI, reduced smoking frequency, and fewer hospital admissions.

The results of this groundbreaking research provide deeper insights into the genetic factors influencing personality, which in turn may help improve our understanding of the relationship between personality traits and overall health outcomes. However, the researchers acknowledge that there are still several gaps in the current understanding of personality genetics, particularly in how these traits manifest across different cultures and languages.

Nonetheless, the findings have the potential to revolutionize our approach to categorising, identifying, and treating various diseases by integrating personality traits into health outcome models.