In a new report published in Nature Neuroscience consisting of over 50,000 case studies analyzed by a large group of scientists internationally have possibly found a link between genetic disposition leading to high risk of alcoholism and psychiatric disorders such as ADHD, schizophrenia and depression. The study’s senior author Arpana Agrawal, Ph.D., a professor of psychiatry at Washington University School of Medicine in St. Louis did make it clear that “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.”
A Problematic Gene
The gene identified as the contributor to risk of alcoholism is the ADH1B gene and regulates how the body converts alcohol to a substance called acetaldehyde. The gene’s natural variation within people created a correlation with the ability of the boy to convert alcohol to acetaldehyde. The people who’s genetics lead to quicker conversion created a ‘protective effect’ leading to less drinking overall. The effects of this gene are also targeted by some medications designed to treat addiction such as Disulfiram (Antabuse).
The study compared genetic variants from nearly 15,000 individuals diagnosed with alcohol dependence to nearly 38,000 people who did not have that diagnosis. The research group found that the risk factors related to alcohol dependence also were linked to risk for other psychiatric disorders, such as depression, schizophrenia, ADHD and the use of cigarettes and marijuana, but were quick to point out that more research from a larger sample size is needed to create a stronger link and support a causation relationship between the two. The study included primarily subjects of European and African descent. “In the future, we need to study much larger numbers of people from non-European populations because we don’t know as much about genetic factors that affect their risk. As our study showed, these factors can differ from population to population” according to Dr. Agrawal.
Further Research Required
While the study provided progress towards suggesting a angle to prescribe treatment, Agrawal remained clear that this study was by no means the end of research into the risks into alcoholism developing in drinkers. “The risk conferred by the ADH1B gene is one of the strongest single-gene effects seen in people with a psychiatric illness, but overall, it explains only a small proportion of the risk,” Agrawal said. “Many additional gene variants are making small contributions to alcoholism risk, but to find them, we’ll need to study more people.”