Genes appear to influence the response of cigarette smokers to smoking cessation therapy with an antidepressant drug, researchers have found. Smokers carrying one form of a gene that affects brain cell receptors to the neurochemical dopamine responded to an antidepressant medicine, the researchers explain, while smokers with another form of the gene did not. The findings were reported here Sunday at the American Cancer Society Science Writers Seminar.
Dopamine is a brain chemical that helps produce feelings of pleasure and satisfaction.
Abnormalities in dopamine activity in the brain have been linked to addiction. That is, we were able to give a particular drug to a group of people who were characterized on the basis of their genetic profile, and show that this drug could work better for them than it could work for others. The researchers ran genetic tests on 134 smokers to determine whether they carried the A1 or A2 form of the DRD2 gene. Individuals with at least one copy of the A1 version of the gene have fewer and less sensitive D2 dopamine receptors than do individuals with two copies of the A2 allele, the researchers explained. This means they have a weaker response to dopamine's effects.