While previous twin studies have consistently shown the importance of genetic influences on various measures of alcohol consumption, a full diagnostic assessment can be complicated and lengthy. This has led some researchers to ask: To what extent do measures of alcohol consumption accurately index the genetic risk for alcohol dependence (AD)? Findings indicate that four relatively simple measures of alcohol consumption were able to capture all (in women) or a very large proportion (in men) of the genetic risk for AD.
Results will be published in the June 2010 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.
"This research has both theoretical and practical implications," explained Kenneth S. Kendler, Banks Professor of Psychiatry at the Virginia Commonwealth University School of Medicine and corresponding author for the study. "Do the detailed clinical assessments of AD symptoms – such as tolerance, loss of control, withdrawal, and desire or inability to cut down – provide additional important information about genetic risk above and beyond that obtained from relatively simple consumption-related; measures such as the ones we tested?"
Kendler and his colleagues assessed a lifetime history of AD in 5,073 (2,090 complete pairs and 893 twins whose co-twins did not participate) same-sex adult twins from the Virginia Twin Registry – using Diagnostic and Statistical Manual-Fourth Edition criteria – against four measures of alcohol consumption at the time of heaviest drinking: drinking frequency, regular quantity, maximum quantity, and drunk frequency.
"We found that four relatively simple measures of alcohol consumption obtained for the time of lifetime heaviest drinking were able to capture all or nearly all of the genetic risk for the DSM-IV diagnosis of alcohol dependence," said Kendler. "We believe that it would be possible for researchers to obtain these relatively simple self-reported measures for the period of heaviest drinking to index genetic risk rather than the more time consuming and difficult diagnostic assessments of AD."
The practical implications of our results are clear, added Kendler. "They show that considerably simpler measures for the period of heaviest drinking may be able to index the same genetic risk factors that are assessed through structured clinical interviews," he said. "In other words, relatively simple measures of drinking behavior can make the process of risk identification both easier and faster for everyone."
Alcoholism: Clinical & Experimental Research (ACER) is the official journal of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism. Co-authors of the ACER paper, "The Relationship between Genetic Influences on Alcohol Dependence and on Patterns of Alcohol Consumption," were: John Myers of the Virginia Institute of Psychiatric and Behavioral Genetics and the Department of Psychiatry at the Virginia Commonwealth University School of Medicine; Danielle Dick of the Virginia Institute of Psychiatric and Behavioral Genetics, the Department of Psychiatry, and the Department of Human and Molecular Genetics at the Virginia Commonwealth University School of Medicine, as well as the Department of Psychology at Virginia Commonwealth University; and Carol A. Prescott of the Department of Psychology at the University of Southern California. The study was funded by the National Institutes of Health. This release is supported by the Addiction Technology Transfer Center Network at http://www.ATTCnetwork.org.