Many people try cigarettes but do not become smokers. Figuring out who does is especially important in adolescence, when the habit often begins. Genetic variations in dopamine transmission can enhance nicotine’s physiological reward. Depression also contributes to adolescent smoking. Audrain-McGovern et al. (p.
1224) examined the influences of depression and two dopamine-related genes on the progression of smoking between grades 9 and 11. Among students who had already taken at least one puff, the number of
SLC6A3 10-repeat alleles did not affect smoking progression. However, each
A1 allele of the gene for the dopamine 2 receptor,
DRD2, nearly doubled the odds of progressing to either greater experimentation or current smoking. Depressive symptoms magnified this effect. These findings suggest that identifying adolescents with depressive symptoms and providing rewarding alternatives to smoking may improve mood and reduce the likelihood of smoking.