American researcher and psychologist Ovide F. Pomerleau, from the Department of Psychiatry, Nicotine Research Laboratory, University of Michigan (Ann Arbor), and fellow colleagues—who specialize in statistical genetics, gene analysis, and trait analysis—studied 435 people who either regularly smoke cigarettes or don’t smoke (but have tried cigarettes at some point in their lives).

Specifically, the non-smokers had smoked at least one cigarette during their lives but no more than one hundred—and had never smoked on a regular basis. The smokers currently smoke at least five cigarettes daily and have done so for at least five years.

The results of the study found that the smokers were eight (8) times more likely when compared to the non-smokers to have a “pleasurable buzz” at the time of their first cigarette.

The results, the researchers state, provide an association that helps to explain the either negative reaction (nausa, cough) or position reaction ("buzz," pleasure) to a person’s first cigarette and to the increased likelihood for a person to become addicted to nicotine.

The Pomerleau team found that a variant in the CHRNA5 nicotine receptor gene causes some people to have an increased susceptibility to nicotine addiction, a lifelong habit of smoking, and increased risk of lung cancer and other adverse medical conditions.

Specifically, the smokers were much more likely, when compared to the non-smokers, to have the less common "rs16969968" form of the CHRNA5 (or, cholinergic receptor, nicotinic, alpha 5) human gene.

Page two contains additional information on nicotine addiction.

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CHRNA5 is a member of nicotinic acetylcholine receptors (nAChRs), which themselves are members of a superfamily of ligand-gated ion channels that provide for the transmission of signals at synapses within the body, such as within the nervous system.

NAChRs receptors are opened (triggered) by neurotransmitter acetylcholine, but also are opened by nicotine.

Nicotine is an alkaloid found in the family Solanaceae, a group of plants called nightshade.

In tobacco, nicotine is the ingredient most responsible for addiction, or the dependence (habit) found with people who smoke cigarettes.

In fact, the American Heart Association states, "Nicotine addiction has historically been one of the hardest addictions to break."

According to the Addiction news article “If your first cigarette gave you a buzz and you now smoke, a gene may be to blame, study shows,” Pomerleus states, “If cigarette smoking is sustained, nicotine addiction can occur in a few days to a few months. 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.”

The journal Addiction is published by the Society for the Study of Addiction to Alcohol and other Drugs.

Pomerleau states, “The cigarette companies have told us for years that smoking is an individual choice. But it is increasingly clear that for some people that isn't really the case." [WebMD: “Gene Linked to Early Nicotine Addiction”]

Page three contains information about other research on the gene responsible for nicotine dependence.

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According to the Addiction news article, “The new findings linking first smoking experiences, smoking habits, and genetic variation build on previous research by Ovide Pomerleau and Cynthia Pomerleau, Ph.D., at U-M. In studies conducted over a 10-year span, they documented a link between nicotine-dependent smoking and positive first smoking experiences.”

In addition, also stated with the Addiction article, “Ovide Pomerleau also credits earlier animal research by his colleagues Allan Collins and Jerry Stitzel at the University of Colorado, for providing the impetus for the idea that initial reactivity to nicotine might set the stage for the development of nicotine dependence — and that nicotine receptor genetic variations underlie this process. Stitzel formerly worked at U-M.”

According to the WebMD article, Pomerleau says, "It really is a triple whammy, People with this genetic makeup find smoking pleasurable from that first cigarette and they are more likely to get addicted and develop lung cancer."

The discovery of this study, along with previous related studies, show that new, more effective therapies are possible at treating people addicted to nicotine. Pomerleau states, "Things are moving really fast in this field. We are making new discoveries all the time." [WebMD]

He adds that more effective treatments are possible within a few years.

The scientific paper summarizing the research study is entitled “Association of a single nucleotide polymorphism in neuronal acetylcholine receptor subunit alpha 5 (CHRNA5) with smoking status and with 'pleasurable buzz' during early experimentation with smoking.”

It was published in the journal Addiction (2008; 103: 1544-1552).

Its authors are: Richard Sherva, John P. Rice, Laura J. Bierut and Rosalind J. Neuman of the Department of Psychiatry at the Washington University School of Medicine; Kirk Wilhelmsen of the Department of Genetics and Neurology at the Carolina Center for Genome Sciences; Ovide Pomerleau, Cynthia S. Pomerleau and Sandy M. Snedecor of the University of Michigan Department of Psychiatry; and Scott A. Chasse of the Department of Biochemistry and Biophysics at the University of North Carolina.