If your first cigarette gave you a buzz and you now smoke, blame a gene

Anyone who has ever tried smoking probably remembers that first cigarette vividly. For some, it brought a wave of nausea or a nasty coughing fit. For others, those first puffs also came with a rush of pleasure or "buzz." Now, a new study links those first experiences with smoking, and the likelihood that a person is currently a smoker, to a particular genetic variation. The finding may help explain the path that leads from that first cigarette to lifelong smoking.

The new finding also adds to growing suspicion surrounding the role of a particular nicotine-receptor gene in smoking-related behaviors and in lung cancer. The regular smokers in the study were far more likely than the never-smokers to have the less common rs16969968 form of the CHRNA5 gene, in which just one base-pair in the gene sequence was different from the more common form. This kind of genetic variation is called a single nucleotide polymorphism or SNP.

Smokers were also eight times as likely to report that their first cigarettes gave them a pleasurable buzz.

"It appears that for people who have a certain genetic makeup, the initial physical reaction to smoking can play a significant role in determining what happens next," says senior author and project leader, Ovide Pomerleau, a professor of psychiatry at the University of Michigan Medical School and founder of the U-M Nicotine Research Laboratory.

"If cigarette smoking is sustained, nicotine addiction can occur in a few days to a few months," he adds. "The finding of a genetic association with pleasurable early smoking experiences may help explain how people get addicted — and, of course, once addicted, many will keep smoking for the rest of their lives."