Genetic, environmental etiologies of suicide attempt, death partially overlap
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Researchers found partial overlap between the genetic and environmental etiologies of suicide attempt and death, according to study results published in American Journal of Psychiatry.
They also found the etiologies to have modest sex differences and to shift across the life course.
“Efforts to directly compare the etiology of suicide attempt and death are difficult where longitudinal data on both outcomes are not available for a large, representative sample, such as when samples are selected as described above,” Alexis C. Edwards, PhD, of the department of psychiatry at the Virginia Commonwealth University School of Medicine, and colleagues wrote. “Furthermore, the relatively low prevalence of suicide attempts and, in particular, suicide deaths has impeded efforts to obtain reliable heritability estimates for these outcomes because of inadequate statistical power. In the near term, these constraints mean that molecular genetic studies are unlikely to be able to elucidate shared versus outcome-specific aspects of etiology.”
Thus, the researchers noted the necessity of utilizing other methodologic approaches to address this research gap. In the current study, they analyzed Swedish national registry data for a large cohort of twin, full siblings and half-siblings comprised of 1,314,990 individuals born between 1960 and 1990 who were followed through 2015. They estimated heritability of suicide attempt and suicide death, as well as genetic environmental associations between them, using twin-family modeling. Further, they evaluated the link between suicide attempt by young people vs. adults.
Results of bivariate models showed moderate heritability for suicide attempt and death among both women and men, with a substantial but incomplete genetic correlation for the outcomes. Edwards and colleagues noted weaker environmental correlations. Individuals aged 10 years to 24 years had stronger heritability of suicide attempt compared with those aged 25 years and older. Women had stronger genetic correlations between attempt during youth and during adulthood compared with men.
“In conjunction with modest environmental correlations, our findings speak to partially distinct etiologies, raising the likelihood of incompletely overlapping opportunities for prevention and risk prediction,” Edwards and colleagues wrote. “Furthermore, as demonstrated by our analysis of suicide attempt across young people and adults, both genetic and environmental influences on risk are temporally dynamic, particularly among men. Efforts to reduce risk for suicidal behavior must therefore consider sex differences and shifts across the life course, and gene identification efforts would benefit from distinguishing between suicide attempts and suicide deaths.”