Scientists Identify 1,260 Genetic Variants Linked To Personality In Largest Study Of Its Kind With 1M Subjects

An international team of researchers has identified 1,260 genetic variants linked to the "Big Five" personality traits, marking the largest study of its kind and offering new evidence that personality has a measurable biological foundation beyond environment and life experience alone.

The study, published Sept. 2 in the journal Nature, was led by researchers including Ted Schwaba of Michigan State University, Michel Nivard of the University of Bristol, and Elliot Tucker-Drob, working through a collaborative research effort called the Revived Genomics of Personality Consortium. The project combined results from 46 different research cohorts spanning 13 to 15 countries, drawing on genetic and personality data from more than 1.1 million participants at its peak sample size, according to figures cited in the research.

Of the 1,260 identified variants, 824 had never previously been linked to personality in earlier research, representing a substantial leap in scale compared with prior studies in the field. For the trait of conscientiousness alone, the number of genome-wide significant genetic locations jumped from just three identified in the most recent prior research to 131 in the new study. Neuroticism, the most extensively studied of the five traits, saw its known genetic locations climb from 224 to 706.

The Big Five personality framework, widely used within psychology, measures five relatively stable and habitual differences in how people think, feel and act: openness to experience, conscientiousness, extraversion, agreeableness and neuroticism. Participants across the 46 cohorts involved in the study provided DNA samples and completed standardized questionnaires measuring these traits, allowing researchers to search for genetic variants statistically associated with each one.

Schwaba, the study's lead author, said the findings underscore just how broadly relevant personality appears to be across nearly every domain of human life.

"Personality seems to be relevant nearly everywhere you look," Schwaba said. "We hope this study will encourage many other scientists to incorporate personality traits into their fields of study. For example, genetic variants associated with neuroticism predict more time spent in the hospital, which is relevant to physicians and health researchers, and variants associated with openness to experience are linked to income and switching jobs, which is relevant to vocational researchers."

Despite identifying more than a thousand genetic variants linked to personality, researchers emphasized that no single "personality gene" exists. Instead, personality traits appear to be influenced by an enormous number of individual genetic variants, each carrying an extremely small effect on its own. According to the study, the median effect size for a genetic variant linked to extraversion corresponds to shifting someone's expected score from roughly the 50th percentile to the 50.35th percentile, an exceedingly modest individual effect that only becomes meaningful in aggregate across more than a thousand variants combined.

Overall, common genetic variants were found to explain between 4.8% and 9.3% of the total variation in personality measures across the population studied, a figure that rose to between 7.6% and 13.4% when researchers used more reliable, longer-form measurement instruments. Those figures remain considerably lower than the broader heritability estimates for personality derived from twin studies, which have historically placed the heritable component of personality between roughly 40% and 60%, reflecting the difference between the specific common genetic variants this study was able to detect and the fuller, more complex genetic architecture believed to underlie personality more broadly.

Michel Nivard, a professor of genomic epidemiology at the University of Bristol and one of the study's authors, explained the broader motivation behind the research in comments to Time magazine.

"We think that personality is super-important for health," Nivard said.

Researchers noted that Big Five personality scores have long been associated with risk for various mental health outcomes, with neuroticism in particular linked to anxiety, and that personality traits more broadly can help predict outcomes such as whether people are likely to consistently take prescribed medication or seek out medical care when facing a health problem.

Beyond identifying the raw genetic variants, researchers used the data to draw connections between personality genetics and a wide range of life outcomes. The study found, for example, that common genetic variants linked to openness to experience predicted a greater likelihood that a person would move to more cosmopolitan neighborhoods later in life, a pattern researchers noted could then reinforce and further shape that same personality trait through the person's new environment. Separately, genetic variants associated with conscientiousness were linked to a person's likelihood of taking up smoking, while variants linked to extraversion were associated with differences in COVID-19 infection risk, and variants tied to agreeableness and openness to experience were linked to a person's likelihood of participating in research studies in the first place.

Denis Bratko, a psychologist at the University of Zagreb in Croatia who studies genetic influences on personality but was not involved in the new research, said the study helps resolve a longstanding challenge in the field. Previous efforts to find clear genetic correlations with personality traits had largely failed to produce consistent results, in part because earlier studies were too small and because personality appears to be influenced by an unusually large number of individual genetic variants, each with only a tiny effect on its own.

To help ensure the associations identified were genuinely genetic rather than reflections of shared family environment or other confounding factors, researchers also incorporated data from within-family genetic association studies, which compare siblings directly in order to control for shared upbringing, covering up to 50,725 participants within that portion of the analysis. According to Nature's coverage of the findings, the genetic links to personality identified in the study proved more robust to such confounding factors than gene associations previously found for traits including education level and income.

Researchers involved in the study were careful to stress that the findings do not suggest personality is fixed or predetermined by a person's genes. Rather, the study's authors described genetics as providing only a basic underlying framework, with environment, culture and individual life decisions continuing to play a substantial role in how personality traits ultimately develop and express themselves over the course of a person's life.

The research team has made the full summary statistics and underlying analytical code from the study publicly available through the Open Science Framework, allowing other researchers to build on the findings. Scientists involved in the project said they hope the newly identified genetic variants will serve as a foundation for future research examining how these biological pathways interact with social and environmental factors, offering a more complete picture not only of the genetic underpinnings of individual personality traits, but of how those traits, in combination with life circumstances, ultimately shape the outcomes people experience across health, career, relationships and beyond.