Genetics and Addiction
If you’ve ever wondered why some people are able to consume a great amount of alcohol and seem to suffer no ill effects, while others become intoxicated with even a negligible amount, a reasonable question is whether there’s a biological reason. Alcoholism, also called alcohol dependence, afflicts some individuals but not others. The fact is that there are genetic components that may help determine if a person is more susceptible to alcohol addiction.
Research shows that if there is a family member with a history of alcoholism, it is more likely that another family member who chooses to drink may also develop alcoholism. What are these genes and how do they work?
Several Genes Linked To Multiple Addictions
In the field of addiction research, scientists and researchers at the University of Virginia (UVA) Health System and the University of Michigan have found that some of the same genes associated with alcohol dependence are also closely linked to additions involving cocaine, heroin, opioids, nicotine and other substances.
Researchers are now working to narrow the scope of specific gene targets. Once they can pinpoint molecular mechanisms and exact genetic variants, it will be possible to create more effective and personalized treatment for people who have multiple addictions.
The latest research points out the specific genomic locations of 11 chromosomes where addictions to cannabis, alcohol, cocaine, heroin, nicotine and opioids are found together in a cluster.
The findings are presented in a paper published in the Nature Reviews Genetics (April 2009), co-authored by Ming Li, Ph.D., professor of psychiatry and neurobehavioral sciences at the UVA School of Medicine, and Margit Burmeister, Ph.D., professor of psychiatry and human genetics at the University of Michigan.
Li points that the comparison of peaks for addiction to multiple substances on certain chromosomal locations “confirms that genetic vulnerability to different substances overlaps, in part.” Ling elaborates that variants in several genes, including aldehyde dehydrogenases, GABRA2, ANKK1, as well as neurexins 1 and 3, have already been associated with addiction to multiple drugs.
Direction For Future Genetics And Addiction Research
Where will the research on genetics and addiction go from here? According to Li, a focus on CHRNA5, CHRNA3, and CHRNB4 clusters as well as other variants is recommended. In other studies, the CHRNA5 cluster has been linked to lung cancer, lifelong smoking and heightened dependence on nicotine.
What is still unknown is the exact nature of the gene variants and how they function. To further the existing information and get closer to understanding the interconnection between genetics and addiction, it will be necessary to do functional studies as well as studies involving ethnic population samples.
Role of Genetics In Addiction
Biology – or the genes you are born with – along with environmental influences, account for about half of an individual’s vulnerability to addiction. There are also other factors that may influence a person’s risk for drug abuse and addiction including gender, presence of mental disorders, and ethnicity.
Pharmacogenomics – An Emerging Science
Research sponsored by the National Institute on Drug Abuse (NIDA) is paving the way toward promising personalized medicine. Pharmacogenomics, an emerging science, seeks to utilize the power of genomic information in order to improve addiction treatments. How individuals respond to treatment varies from patient to patient. Clinicians know that much of this variance is due to genetic factors.
Genes influence the types and numbers of receptors in our brains, how we respond to different medications, and how quickly drugs are metabolized in our bodies. One NIDA-sponsored study of alcohol dependent patients with a specific opioid receptor gene variant and were treated with naltrexone had significantly lower rates of relapse.
Identification of and targeting the gene variants and molecular mechanisms will help researchers develop new medicines for treatment of alcoholism and other addictions.
