A new study comes to flesh out our understanding of the genetic basis for problematic drinking.

Previously, we knew of 13 gene variants associated with heavy drinking. Now, this study expands our knowledge to an impressive 29 different gene variants linked to problematic alcohol use. One limitation of the study is that, despite its relatively large sample of 435,000 people, all of them were of European descent.

Bottoms up

“The new data triple the number of known genetic risk loci associated with problematic alcohol use,” said Joel Gelernter at Yale University School of Medicine, the Foundations Fund Professor of Psychiatry and a professor of genetics and neuroscience.

Foundations Fund Professor of Psychiatry and professor of genetics and of neuroscience, who is the senior author of the multi-institutional study.

The study looked at genome-wide records of people of European ancestry contained in four separate biobanks and datasets. The team identified individuals who met criteria for problematic drinking, including alcohol use disorder and alcohol use with medical consequences and then looked for genetic variants they all shared.

They located 19 previously-unknown genes that represent risk factors for such behavior, alongside 10 previously-identified genes.

Furthermore, they looked at genetic risk factors for several psychiatric disorders including anxiety disorder and depression in the genomes. During the study, this step allowed them to analyze the genetic links between such disorders and heavy drinking. Major depressive disorder showed the greatest correlation to problematic drinking; risk-taking behavior, insomnia were also positively correlated with such behavior.

The genes identified in this study are particularly stable from a hereditary point of view in the brain (they’re more stable across generations) and in “evolutionarily conserved regulatory regions of the genome”, which suggests that they perform important functions in our metabolism. Exactly what these functions remain to be determined.

“This gives us ways to understand causal relations between problematic alcohol use traits such as psychiatric states, risk-taking behavior, and cognitive performance,” said Yale’s Hang Zhou, associate research scientist in psychiatry and lead author of the study. “With these results, we are also in a better position to evaluate individual-level risk for problematic alcohol use,” Gelernter said.

Heavy drinking is associated with adverse medical and social outcomes, so understanding which people are at risk for such behavior could help us better protect them.

The paper “Genome-wide meta-analysis of problematic alcohol use in 435,563 individuals yields insights into biology and relationships with other traits” has been published in the journal Nature Neuroscience.