The Genetics of Addiction
Ming D. Li, PhD
Jean and Ronald Butcher Professor
Head, Section of Neurobiology
Vice Chair for Research, Department of Psychiatry and NB Sciences
University of Virginia
Smoking is currently the greatest preventable cause of cancer, accounting for at least 30 percent of all cancer deaths and 87 percent of lung cancer incidents. Present research shows that 40 to 60 percent of the smoking addiction is due to some genetic factor. The present studies aimed to identify which specific gene(s) contribute to addiction. The Mid-South Tobacco Family study sampled 2,037 smokers. Results revealed that a region near the gene GABBR2 is linked to nicotine dependence, whereas only a weak association was made between GABBR1 and nicotine dependence. Yet these two genes (GABBR1 and GABBR2) come together to function as a receptor, so together, they contribute to genotype addiction. The Framingham Heart study suggested a linkage between chromosome 9 and nicotine dependence in three independent samples. These findings indicate that there is no single gene responsible for addiction. Instead, multiple genes and environmental interaction results in the expression of addiction. Future studies should focus on finding out which treatment is effective for addiction, and that treatment efforts should focus on likely smokers.