ど高くないと考えてしまうだろう．しかしもし個人の自
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比の高いグループ10にいれば対応は変わってくるであろ
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86
自殺と遺伝
Abstract
GENETIC STUDY OF SUICIDE
Akitoyo Hishimoto, M.D. Ph.D.
Department of Psychiatry, Yokohama City University Graduate School of Medicine
Suicide is one of the leading causes of death among persons under 50 years of age in Japan. The increase in the
suicide rate because of the recent COVID-19 pandemic, which has brought on economic difficulties, social isolation,
psychological distress, and so on, has been deeply concerning. Individual background characteristics related to
suicidal behavior are various, such as employment, poverty, pain due to sickness, and bullying. However,
epidemiological evidence, such as family, twin, and adoption studies, has indicated a high degree of heritability for
suicide. We now have one of the largest genomic samples related to completed suicide thanks to the cooperation of
bereaved families, and we recently performed a first genome-wide association study (GWAS) for completed suicide
in the Japanese population (746 completed suicides vs. 14,049 controls). We are the first to have demonstrated
biological evidence of "suicide heritability" by a new approach of GCTA and polygenic risk score (PRS) analysis.
We found around 40% SNP heritability, which is almost equal to that for schizophrenia and bipolar disorder. In
addition, we have shown the possibility of clinical applications in which individual PRS may predict suicide risk. In
the near future, we may be able to identify the genetic locus related to susceptibility to suicide and predict suicide
more precisely with a larger sample size.
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