Personality Traits and
Psychiatric Disorders Linked to Specific Genomic Locations
Researchers
also find correlations between traits and distinct disorders
By Scott LaFee,
December
08, 2016 -- A meta-analysis of genome-wide association studies (GWAS) has
identified six loci or regions of the human genome that are significantly
linked to personality traits,
report researchers at University
of California San Diego School of Medicine in this week’s advance online
publication of Nature Genetics.
The findings also show correlations with psychiatric disorders.
“Although personality traits are
heritable, it has been difficult to characterize genetic variants associated
with personality until recent, large-scale GWAS,” said senior author Chi-Hua
Chen, PhD, assistant professor in the Department of Radiology at UC San Diego
School of Medicine.
Five psychological factors are
commonly used to measure individual differences in personality:
- Extraversion (versus
introversion) reflects talkativeness, assertiveness and a high activity
level
- Neuroticism (versus
emotional stability) reflects negative affect, such as anxiety and
depression
- Agreeableness (versus
antagonism) measures cooperativeness and compassion
- Conscientiousness
(versus undependability) indicates diligence and self-discipline
- Openness to experience
(versus being closed to experience) suggests intellectual curiosity and
creativity
Psychologists and others define
personality phenotypes — sets of observable characteristics — based upon
quantitative scoring of these five factors. Past meta-analyses of twin and
family studies have attributed approximately 40 percent of variance in
personality to genetic factors. GWAS, which look for genetic variations across
a large sampling of people, have discovered several variants associated with
the five factors.
In their new paper, Chen and
colleagues analyzed genetic variations among the five personality traits and
six psychiatric disorders, using data from 23andMe, a privately held personal
genomics and biotechnology company, the Genetics of Personality Consortium, a
European-based collaboration of GWAS focusing on personality questions, UK
Biobank and deCODE Genetics, an Iceland-based human genetics company.
The researchers found, for
example, that extraversion was associated with variants in the gene WSCD2 and
near gene PCDH15; neuroticism was associated with variants on chromosome 8p23.1
and gene L3MBTL2. Personality traits were largely separated genetically from
psychiatric disorders, except for neuroticism and openness to experience, which
clustered in the same genomic regions as the disorders.
In addition, there were high
genetic correlations between extraversion and attention deficit hyperactivity
disorder (ADHD) and between openness and schizophrenia and bipolar disorder.
Neuroticism was genetically correlated with internalized psychopathologies,
such as depression and anxiety.
“We identified genetic variants
linked to extraversion and neuroticism personality traits,” said Chen. “Our
study is in an early stage for genetic research in personality and many more
genetic variants associated with personality traits are to be discovered. We
found genetic correlations between personality traits and psychiatric
disorders, but specific variants underlying the correlations are unknown.”
The authors note that while the
sample size of the meta-analyses was large (123,132 to 260,861 participants in
different studies), they used only GWAS summary statistics and cannot estimate
all genetic variance factors; some studies also used different methodologies.
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