A National Swedish Longitudinal Twin-Sibling Study of alcohol use disorders among males

Abstract

Aims To examine whether genetic influences on the development of AUD during emerging adulthood through mid-adulthood are stable or dynamic. Design A twin study modeling developmental changes in the genetic and environmental influences on AUD over three age periods (18–25, 26–33, and 33–41) as a Cholesky decomposition. Setting Sweden. Participants Swedish male twin pairs (1,532 monozygotic and 1,940 dizygotic) and 66,033 full male sibling pairs born less than two years apart. Measurements AUD was identified based on Swedish medical and legal registries. Findings The best fitting model included additive genetic and unique environmental factors, with no evidence for shared environmental factors. Although the total heritability was stable across time, there were two major genetic factors contributing to AUD risk, one beginning at ages 18–25 with a modest decline in importance over time, and another of less impact beginning at ages 26–33 with a modest increase in importance by ages 33–41. Conclusions The heritability of AUD was stable across the three age periods. Two sets of genetic risk factors contributed to AUD risk, with one originating during the ages 18–25 and another coming online at ages 26–33, providing support for the developmentally dynamic hypothesis.

Continuity of genetic and environmental influences on clinically assessed major depression from ages 18 to 45

“…One may, therefore, use heterogenous samples without worrying that they might be identifying distinct genetic risk variants acting at different ages. This is unlike for instance for alcohol use disorder, where changing genetic influences has been found during adulthood (Long et al ., 2017; Torvik et al ., 2017). There are, however, indications that the genetic effects for MDD could be different in childhood, early adolescence and old age (Gillespie et al ., 2004; Nivard et al ., 2015; Petkus et al ., 2016; Waszczuk et al ., 2016).…”

Rich club and reward network connectivity as endophenotypes for alcohol dependence: a diffusion tensor imaging study

“…First-degree relatives of patients with AUD are at greater risk of developing the disorder and heritability of AUD is estimated at 50-85% (Long et al 2017;Verhulst, Neale & Kendler 2016), suggesting a large familial component to the disorder. Therefore, the investigation of unaffected first-degree relatives, in addition to AUD patients and healthy controls, may help to distinguish biomarkers of genetic risk without the confounding effects of the burden of illness, medication or clinical state.…”

Birth order and health events attributable to alcohol and narcotics in midlife: A 25-year follow-up of a national Swedish birth cohort and their siblings

“…Substantial evidence shows that there are significant environmental and genetic influences on the development and transmission of substance use disorders ( Kendler et al, 2016 , 2021 ). Further, these influences may have differential effects for the development and transmission of substance use disorders during discrete life course stages ( Long et al, 2017 ). Future research is needed to provide additional insights into the potentially time-inconstant contributions of family background and these outcomes throughout the life course.…”