Study identifies genetic variant that may contribute to alcohol and drug addiction

People with a genetic variant of a neurotransmitter gene may have an increased risk of addiction to alcohol and other substances later in life if they were exposed to childhood stress, such as divorce or emotionally distant parents, and other adverse experiences, according to recent research.
A study led by researchers at the University of Oklahoma College of Medicine in collaboration with researchers from the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health, focused on an inherited variant of the gene for the enzyme catechol‐O‐methyltransferase (COMT). “This is a well-known genetic variant of COMT, common worldwide, that leads to lower activity of this enzyme, and that has been previously observed to alter brain responses to stress and cognitive challenges,” stated study co-author, David Goldman, M.D., Chief of NIAAA’s Laboratory of Neurogenetics. COMT does so by helping the body manage levels of neurotransmitters, including dopamine, that are released when a person drinks alcohol or takes a drug like amphetamine.
The study included 480 healthy young adults ages 18–30 years of age who had experienced varying amounts of early-life adversity during childhood and adolescence. The researchers found that people who experienced early life stress and had the genetically less active COMT variant were more vulnerable and started drinking at a younger age. This heightened vulnerability often led to consumption of alcohol and illicit drugs prior to the age of 15 years, a predictor for alcohol and other substance use disorders in later life.
These findings demonstrate the interplay between a person’s genetic makeup and adverse environmental factors during childhood to alter the risk of alcohol and other substance use disorders later in life. Although no single gene alone strongly predicts risk of addiction, some genes predict risk more strongly in the context of environmental exposures.
Source: Early-life adversity and blunted stress reactivity as predictors of alcohol and drug use in persons with COMT (rs4680) Val158Met genotypes. Lovallo WR, Cohoon AJ, Sorocco KH, Vincent AS, Acheson A, Hodgkinson CA, Goldman D. Alcohol Clin Exp Res. 43(7):1519-1527.