Gene That Influences Alcohol Consumption Identified

ScienceDaily (Dec. 6, 2007) — A variant of a gene involved in communication among brain cells has a direct influence on alcohol consumption in mice, according to a new study. Scientists do not know yet whether a similar gene variant, with a similar effect on alcohol consumption, exists in humans.

Known as Grm7, the gene encodes a receptor subtype that inhibits the release of glutamate and other neurotransmitter molecules that brain cells use to communicate with one another. Researchers identified a gene variant, or polymorphism, that reduces the abundance of Grm7 messenger RNA (mRNA) in brain tissue. mRNA is the molecular intermediate between a gene and its protein product. Mice that possess this gene variant drink more alcohol than do mice with higher brain levels of Grm7 mRNA. A report of the study appears as an online Article in Press in Genomics.

"This is a noteworthy contribution, particularly since identifying genes that predispose to alcohol-related behaviors is such an arduous task," says NIAAA Director Ting-Kai Li, M.D.

Scientists have long known that genes account for a significant proportion of the risk for alcoholism. However, the fact that there are multiple such genes that interact with each other and with multiple environmental factors to influence drinking behavior has hampered studies aimed at isolating individual genes.

"Controlling for this background noise -- the various gene-gene and gene-environment interactions -- presents considerable methodological challenges," notes first author Csaba Vadasz, Ph.D., professor of psychiatric research in the department of psychiatry at New York University School of Medicine, and Director of the NeuroBehavioral Genetic Research Program at the Nathan Kline Institute in Orangeburg, N.Y.

To overcome these difficulties, Dr. Vadasz and colleagues applied a variety of genetic and analytic techniques to animals having nearly identical genetic background, but differing in their preference for alcohol, to identify a chromosomal region, and ultimately the Grm7 gene, associated with alcohol preference.

"Our findings support emerging evidence of the critical role that the brain's glutamate pathways play in addiction," says Dr. Vadasz. "While dopamine has traditionally been cast as a central actor in the neurochemistry of substance use and abuse, recent studies indicate that glutamate systems play an important role in reinforcement and addiction."

If further studies show that a similar gene variant is relevant to alcohol problems in humans, the finding by Dr. Vadasz and colleagues may lead to new opportunities for developing drugs to treat alcohol dependence. Dr. Vadasz speculates that such drugs might be designed to control the level of the Grm7 gene product or modulate the activity of the gene product itself.

This study was supported by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health (NIH), and the U.S. Army.

Adapted from materials provided by NIH/National Institute on Alcohol Abuse and Alcoholism.

Depression and Drinking

Depression and stopping drinking
There is evidence that, although many heavy drinkers feel depressed when they are drinking, most will feel better within a few weeks of stopping. So, it is usually best to tackle the alcohol first, and then consider dealing with the depression if it has not lifted after a few weeks.

After a few alcohol-free weeks, you will probably feel fitter and less depressed. Friends and family may find you easier to get on with. If your feelings of depression lift, this strongly suggests that they were caused by the drinking.

If the depression is still with you after four weeks of not drinking, talk to your GP or about further help. It may be useful to talk about your feelings, particularly if your depression seems linked to relationship problems, unemployment, divorce, bereavement or some other loss. Counselling may be helpful.

If the depression does not lift and is particularly severe, your general practitioner may recommend a talking treatment called 'cognitive psychotherapy' or suggest anti-depressant medication. In either case, you will need to stay away from alcohol and go on with the treatment for several months. There are some medications used to reduce the craving for alcohol, but these are usually only prescribed by a specialist.

Treatment for both alcohol problems and depression can be very successful. It helps to regularly see someone you can trust, either your own doctor, counsellor or a specialist psychiatrist. Changing our habits and style of life is always a challenge and takes time to achieve.