Researchers identified more than a hundred genetic regions associated with neuroticism, a trait used to gauge personality that is also associated with risk factors for depression and schizophrenia.
For this, the largest study ever done on neuroticism, scientists used data from many studies in what researchers call a “meta-analysis.”
Altogether the study includes data from almost half a million people, including from 23andMe customers who consented to participate in research.The study led by Danielle Posthuma, a statistical geneticist at the Vrije Universiteit Amsterdam, identified 136 genes associated with neuroticism.
“Neuroticism is an important risk factor for depression,” said Posthuma. “Hence, insights into the biological mechanisms underlying neuroticism may eventually be informative for the development of drugs to treat depression. Our study is the most comprehensive study into the genetics and biological mechanisms of neuroticism to date, and provides very specific starting points for follow-up studies.”
The study, published in the journal Nature Genetics, was also able to show two distinct clusters for the neuroticism, one around “worry” and the other for what is called “depressed affect,” which describes a state of reduced emotional expression often associated with schizophrenia. In a parallel meta-analysis that also included data from 23andMe and was published in Nature Genetics, Posthuma and her team found found 205 loci associated with intelligence offering a deeper look at the neurobiology of cognitive function. That study also found associations between those genetic regions and “intelligence-linked” genes, and associations with educational attainment, Alzheimer’s disease and ADHD. The researcher “suggest protective effects of intelligence (against) Alzheimer’s disease and ADHD,” but it is linked to an increased risk for autims.
This research is the latest in a series of studies that have illuminated the underlying genetic basis for cognitive function, personality traits and psychiatric disorders. The research around personality have included work on the genetics around the so-called called “Big Five” personality traits — neuroticism, extraversion, openness, agreeableness, and conscientiousness.
On that spectrum of traits, a high level of neuroticism is associated with various mental and physical health issues including depression, anxiety, and substance abuse. High levels of neuroticism are also associated with schizophrenia.
By revealing genes associated with neuroticism, this study adds to our understanding of the underlying neurobiology of the condition. The study points to genes and gene regions involved in neurogenesis, or the process of neuron production in the brain, as well as other processes involving neural stem cells and nerve cells in the brain.
“These results are a major step forward in understanding the neurobiology of neuroticism and provide clear clues for functional follow-up experiments,” the study authors said.