School of Medicine

Alcohol dependence, psychiatric disorders share genetic links

Key alcoholism gene influences how quickly body metabolizes alcohol

From the WashU School of Medicine News

In the largest study of genetic factors linked to alcohol dependence, an international team of researchers identified a gene known to affect risk and determined that many other genes also contribute to risk for alcohol dependence to a lesser degree. In addition, the study linked genetic factors associated with alcohol dependence to other psychiatric disorders, such as depression, and showed that genetic factors tied to typical drinking sometimes are different from those linked to alcohol dependence.

The new analysis, from the Substance Use Disorders working group of the Psychiatric Genomics Consortium, adds to the current understanding of alcohol dependence, a complex disorder influenced by genes, environment and their interactions.

The gene that was conclusively associated with risk of alcohol dependence regulates how quickly the body metabolizes alcohol. The effects of other genes weren’t big enough to reach statistical significance individually — even though this study involved more than 50,000 people — but their combined effects were significant.

The goal of the research was to better understand how genes may contribute to alcohol problems as a way to develop improved and more personalized treatments.

The study is published online Nov. 26 in the journal Nature Neuroscience.

“The current estimate is that one in eight Americans suffers from alcohol dependence,” said senior author Arpana Agrawal, PhD, a professor of psychiatry at Washington University School of Medicine in St. Louis. “And the gene we identified has a protective effect, but by no means is it the only thing affecting risk of alcohol dependence. We know environmental factors also play a role. We also think the genetic susceptibility to alcohol dependence stems from the small, cumulative effects of a very large number of variants across the genome.”

The analysis compared genetic variants from nearly 15,000 individuals diagnosed with alcohol dependence to nearly 38,000 people without such a diagnosis.

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