Scientists have found a new method that could help illuminate the many genetic variants that contribute to personality traits and psychological disorders.
Both genetics and environmental factors influence personality. Estimates suggest that as much as 50 percent of the variance in personality among individuals is influenced by genetics, and in recent years ever-larger genome-wide association studies have been able to identify some of those genetic associations.
But consistently finding these clues is difficult in part because there are a large number of genetic variants that individually have a small effect but together exert an influence on personality and psychological disorders.
So researchers at the University of California at San Diego created this new method for improving the statistical power for gene discovery looking specifically at neuroticism, one of the so-called “Big Five” traits for measuring personality. People with high neuroticism scores tend to respond worse to stress and be moodier than average. Neuroticism is associated with various mental and physical health issues including depression, anxiety, and substance abuse, and high levels of neuroticism are associated with schizophrenia.
Using data from about 60,000 23andMe customers who consented to participate in research, as well as data from the UK Biobank and the international Genetic Personality Consortium, the researchers combined two statistical tools — relative enrichment scores and false discovery rates — as a way to extract more information regarding the genetic variants associated with the trait.
This method helped the researchers improve the statistical power of what would be a traditional large-scale genome-wide association study, revealing underlying genetic associations that couldn’t be seen otherwise. In this case, they found five genetic variants in four different genes or gene regions. Variants in one of those genes, EP300, are associated with schizophrenia.
“These genetic and phenotypic findings suggest that neuroticism might share the same biological pathways with psychiatric disorders,” the researchers concluded in the paper.
The researchers said they were able to increase “power for gene discovery for neuroticism.” Beyond that, the researchers argue that the model demonstrates, “that this statistical framework is a promising tool for improving gene discovery using existing (genome-wide association study) summary statistics.”
Go to the Journal of Human Molecular Genetics to read more about this study.