Decades of psychology have categorised human personality into five broad buckets: openness to experience (curiosity and imagination), conscientiousness (organisation and responsibility), extraversion (sociability), agreeableness (compassion), and neuroticism (a tendency towards anxiety and volatility).
In new findings published in Nature, scientists have completed one of the largest-ever genetic analyses of these ‘big five’ traits, offering a more detailed picture of the genetic architecture of personality.
“The finding that genetic signals were broadly consistent across different contexts … supports the view that personality traits such as extraversion and neuroticism have a biological basis,” Veena Kumari, professor of Experimental Psychology at Brunel University London, said. “However, like most psychological constructs, personality is a complex phenotype.” She noted that human behaviour remains deeply tethered to its environment and “may not be similarly expressed, or even measured with the same precision” across different walks of life.
Inside the genome
The global team of researchers analysed data from up to 1.14 million participants across 46 study cohorts. Participants first completed validated personality questionnaires, which allowed the researchers to assign each person a score for the five traits.
The researchers then analysed the participants’ DNA using a genome-wide association study (GWAS). That is, they looked across the genome for tiny genetic differences that tended to occur more often in people with higher or lower scores on each personality trait.
“The study identified some 1,250 DNA [variations] that are associated with personality traits,” Mani Ramaswami, professor of neurogenetics at Trinity College Dublin, said. “It is important to note that these are tiny changes in the DNA and not the genes as a whole. Each one on its own has a minuscule effect” on human behaviour.
The goal of this exercise was not to find a single piece of DNA that determines whether someone is outgoing or anxious but to spot patterns spread across the genome in the form of genetic variants that, taken together, could be associated with small differences in personality across a large number of people.
Genes and life
The findings reinforced a long-standing idea in genetics that there is no single ‘personality gene’. The dataset also directly challenged older theories that attempted to link traits to particular brain chemicals.
The team found several gene variants scattered across the DNA, and tallied them up into a single number called a polygenic index — a score that combines the effects of the variants, each associated with specific traits.
The researchers then used these scores to test whether the genetic patterns associated with personality turned up in other parts of the people’s lives. Specifically, by comparing these indices with large publicly available datasets on health, behaviour, and social outcomes, they found a range of genetic connections. For example, genetic patterns associated with higher conscientiousness were linked to a lower body mass index, fewer hospital visits, and lower substance use. Genetic patterns associated with neuroticism, on the other hand, showed strong associations with anxiety, depression, and other psychiatric disorders.
Seeing DNA linked to such serious health outcomes might make the index sound like a genetic crystal ball. Michel Nivard, professor of genetic epidemiology at the University of Bristol, is quick to burst that bubble.
“Look, if you want to know more about your personality, you can take a 3-5 minute online test. It’ll be highly predictive,” Dr. Nivard said. For an individual, he said, the genetic effect “is weak, and adds no information over a 3-5 minute test at all.”
Instead, the breakthrough’s true value is at the macroscopic level. The genetic data is “strong enough to do new kinds of psych-, bio-, and social science of personality in larger groups,” Dr. Nivard said, “where we work with averages across many individuals.”
Beyond correlations
Hemant Tiwari, professor of Biostatistics at the University of Alabama at Birmingham, warned against jumping to conclusions like having a neurotic personality could cause someone to become depressed.
He noted that human biology is messy, and “shared genetic influences can affect personality, psychopathology, cognition, self-regulation, and health simultaneously.”
In other words, the same genes that shape our temperament may also trigger certain health issues, rather than one causing the other. Because the data cannot reliably separate the two, Dr. Tiwari said, “whether personality itself causally drives downstream outcomes remains unresolved.”
The genetic correlations extend beyond health into social behaviour and residential choices as well. The study found that by middle age, people with genetic profiles associated with higher openness to experience were more likely to have moved into cosmopolitan professional areas. Meanwhile, those with genetic profiles associated with higher conscientiousness were more likely to have moved away from cosmopolitan areas and toward affluent suburban communities.
The researchers also tried untangling nature from nurture by looking at siblings in their data. Siblings share the same upbringing but inherit slightly different combinations of DNA. By comparing them, the researchers could strip away the effects of the childhood environment and isolate the direct impact of genetics.
While parents still shape their children in complex ways, the data show the environmental transfer of personality is neither strong nor straightforward. As Dr. Nivard noted, the findings largely exclude “the possibility that extraverted parents environmentally cause their kids to be more extraverted”.
Sequencing within families
Translating these insights into global clinical practice, however, faces a severe bottleneck. The genomic databases powering this research are dominated by individuals with European-like genomes. When a polygenic index built on such data is applied to populations with different genetic ancestries, prediction generally becomes less reliable.
Moving forward, Dr. Ramaswami said DNA sequencing within families exhibiting extreme behavioural variants will be far more useful than broad population studies.
An approach along these lines, he noted, is already being pioneered in India for psychiatric conditions through a joint effort by the National Centre for Biological Sciences (NCBS) and the National Institute of Mental Health and Neurosciences (NIMHANS), both in Bengaluru.
Anirban Mukhopadhyay is a geneticist by training and science communicator from New Delhi.
Published – October 28, 2026 07:30 am IST
