While both environmental and genetic factors contribute to the risk of developing alcohol dependence, it is believed to be a largely heritable - 52 to 64 percent - disease.
Previous research had found a significant association between risk for alcoholism and DNA sequence variations called single nucleotide polymorphisms (SNPs) within the GABRA2 gene. New findings indicate that the GABRA2 genotype can modify overall drinking behavior, and may also have an impact on the success of certain types of alcohol psychotherapy.
Results are published in the November issue of Alcoholism: Clinical & Experimental Research.
“The Collaborative Study on the Genetics of Alcoholism (COGA) first reported an association between alcoholism and GABRA2 , based on fine mapping of the region … by a genomic scan and linkage analysis,” explained Henry R. Kranzler, professor of psychiatry at the University of Connecticut Health Center and corresponding author for the study. “We later showed that a high-risk GABRA2 allele was associated with a blunted subjective response to alcohol among healthy subjects in a human laboratory study. We considered that this allele might predict drinking behavior in alcoholics in treatment, so we designed a study to identify patient predictors of treatment response to specific psychotherapies that were clearly differentiated.”
“This was an important research step because one of the main goals of work on the human genome is that genetic information will someday be used to match individuals with the treatments that are most likely to work for them,” said Kent Hutchison, a professor at the University of New Mexico and director of the Neurogenetics Core at the MIND Institute. “This is one step toward realizing that potential.”
Kranzler and his colleagues used data collected through Project MATCH, a multi-center randomized clinical trial evaluating the efficacy of three types of psychosocial treatment for alcoholism: Cognitive Behavioral Therapy (CBT), Motivational Enhancement Therapy (MET), and Twelve Step Facilitation (TSF). The researchers collected DNA samples from 812 European-American subjects (596 men, 216 women), and followed their passage through 12 weeks of treatment and a 12-month post-treatment period.
Results indicate that the GABRA2 genotype can modify overall alcohol intake.