Philadelphia, PA, 18 October 2010 - Alcohol is one of the most commonly abused substances, and men are up to twice as likely to develop alcoholism as women. Until now, the underlying biology contributing to this difference in vulnerability has remained unclear.
A new study published in Biological Psychiatry reveals that dopamine may be an important factor.
Researchers from Columbia and Yale studied male and female college-age social drinkers in a laboratory test of alcohol consumption. After consuming an alcoholic or non-alcoholic drink, each participant underwent a specialized positron emission tomography (PET) scan, an imaging technique that can measure the amount of alcohol-induced dopamine release.
Dopamine has multiple functions in the brain, but is important in this context because of its pleasurable effects when it is released by rewarding experiences, such as sex or drugs.
Despite similar consumptions of alcohol, the men had greater dopamine release than women. This increase was found in the ventral striatum, an area in the brain strongly associated with pleasure, reinforcement and addiction formation.
"In men, increased dopamine release also had a stronger association with subjective positive effects of alcohol intoxication," explained Dr. Nina Urban, corresponding author for this study. "This may contribute to the initial reinforcing properties of alcohol and the risk for habit formation."
Dr. Anissa Abi-Dargham, senior author on this project, notes that "another important observation from this study is the decline in alcohol-induced dopamine release with repeated heavy drinking episodes. This may be one of the hallmarks of developing tolerance or transitioning into habit."
These findings indicate that the ability of alcohol to stimulate dopamine release may play an important and complex role in its rewarding effects and abuse liability in humans. This identification of an in vivo neurochemical mechanism that could help explain the sex difference in alcoholism is an exciting step forward in alcoholism research.
Notes to Editors
The article is "Sex Differences in Striatal Dopamine Release in Young Adults After Oral Alcohol Challenge: A Positron Emission Tomography Imaging Study With [11C]Raclopride" by Nina B.L. Urban, Lawrence S. Kegeles, Mark Slifstein, Xiaoyan Xu, Diana Martinez, Ehab Sakr, Felipe Castillo, Tiffany Moadel, Stephanie S. O'Malley, John H. Krystal, and Anissa Abi-Dargham. Urban, Kegeles, Slifstein, Xu, Martinez, Sakr, Castillo, Moadel, and Abi-Dargham are affiliated with New York State Psychiatric Institute and Columbia University, New York, New York. O'Malley and Krystal are affiliated with Yale University, New Haven, Connecticut. The article appears in Biological Psychiatry, Volume 68, Issue 8 (October 15, 2010), published by Elsevier.
The authors' disclosures of financial and conflicts of interests are available in the article.
Full text of the article mentioned above is available upon request. Contact Chris J. Pfister at firstname.lastname@example.org to obtain a copy or to schedule an interview.
About Biological Psychiatry
This international rapid-publication journal is the official journal of the Society of Biological Psychiatry. It covers a broad range of topics in psychiatric neuroscience and therapeutics. Both basic and clinical contributions are encouraged from all disciplines and research areas relevant to the pathophysiology and treatment of major neuropsychiatric disorders. Full-length and Brief Reports of novel results, Commentaries, Case Studies of unusual significance, and Correspondence and Comments judged to be of high impact to the field are published, particularly those addressing genetic and environmental risk factors, neural circuitry and neurochemistry, and important new therapeutic approaches. Concise Reviews and Editorials that focus on topics of current research and interest are also published rapidly.
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