TOBACCO ADDICTION

Smoking is a very complicated behavior. Somewhere between 60 and 80 percent of people have tried or taken at least a "puff on a cigarette. Why is it that some walk away from cigarettes and others get hooked? For one thing, smoking is a very efficient drug delivery system. It gets the drug to the brain in just a few seconds, much faster than it would travel if injected. A pack-a-day smoker experiences 70,000 “hits” or pairings, per year. In pairing, an environmental cue triggers a craving for nicotine. Simple parings, such as drinking a cup of coffee, sitting in a car, finishing a meal, or having a beer, induce nicotine craving. Some college students, who "only smoke occasionally," find it hard to quit because of these paired associations. For example, when an occasional smoker goes through a half pack of cigarettes while out drinking, this smoker experiences 100 "hits," or chemical pairings between alcohol and tobacco, in one evening, and within a month, this reaches 800 pairings. The brain gets used to that pairing and cries out in displeasure when the association is missing. It is easy to see how stopping even occasional use can be very difficult.

Why does this association occur? Recently, scientists have found that one explanation might lie in a person's genes. Two different twin studies found genetic factors to be more influential than environmental factors in smoking initiation and nicotine dependence. Researchers found that two specific genes may influence smoking behavior by affecting the action of the brain chemical dopamine. Understanding the influence of genetics on nicotine addiction will be crucial to the development of more effective treatments for smoking cessation.

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