Regis Duvignau/Reuters
In Brief:
The brain of an addicted smoker treats nicotine as if it is essential for survival.
Genetic traits may predispose some smokers to stronger addiction.
Most smokers try to quit unaided, resulting in a high failure rate.
If you smoke, no one needs to tell you how bad it is. So why haven’t you quit? Why hasn’t everyone?
Because smoking feels good. It stimulates and focuses the mind at the same time that it soothes and satisfies. The concentrated dose of nicotine in a drag off a cigarette triggers an immediate flood of dopamine and other neurochemicals that wash over the brain’s pleasure centers. Inhaling tobacco smoke is the quickest, most efficient way to get nicotine to the brain.
“I completely understand why you wouldn’t want to give it up,” said Dr. David Abrams, an addiction researcher at the National Institutes of Health. “It’s more difficult to get off nicotine than heroin or cocaine.”
Smoking “hijacks” the reward systems in the brain that drive you to seek food, water and sex, Dr. Abrams explained, driving you to seek nicotine with the same urgency. “Your brain thinks that this has to do with survival of the species,” he said.
Nicotine isn’t equally addictive for everyone. A lot of people do not smoke because they never liked it to begin with. Then there are “chippers,” who smoke occasionally but never seem to get hooked. But most people who smoke will eventually do it all day, every day.
New discoveries in genetics may explain why certain people take to smoking with such gusto and end up so addicted. Some people, for instance, produce a gene-encoded enzyme that clears nicotine from their bloodstreams rapidly, so they tend to smoke more and develop stronger addictions. Others possess special receptors in the brain that bond extra tightly with nicotine, giving them an especially intense high that makes it harder to quit.
Drug makers are exploiting the science of addiction to create novel treatments to help smokers quit. The newest stop-smoking medication, the first to be approved in 10 years, is called Chantix. Available by prescription, Chantix masquerades as nicotine well enough to occupy the brain’s nicotine receptors, where it may lessen cravings. Real nicotine, when it comes along, cannot find enough free receptors to do its thing.
Chantix seems to have a higher success rate than Zyban, an antidepressant that helps to balance dopamine levels. And recently released federal guidelines to doctors for helping smokers quit reported that the drug, combined with the nicotine replacement patch and use of nicotine nasal spray or gum as needed, produced higher long-term abstinence than the patch alone.
Doctors have written millions of prescriptions for Chantix, though enthusiasm for the drug was tempered by reports of suicide and bizarre behaviors in people taking it. The reports prompted the Food and Drug Administration to issue a safety warning about Chantix early in 2008.
“That’s something that needs to be taken very seriously, but it needs to be put in the context of what happens if you don’t quit smoking,” said Dr. Michael Fiore, a smoking cessation specialist at the University of Wisconsin and chairman of the government panel that issued the new guidelines. Dr. Fiore used to consult for Pfizer, the maker of Chantix, but said he cut those ties in 2005. He still prescribes the drug but now takes care to discuss the safety warning with patients.
Dr. Nancy Rigotti was involved in Chantix studies conducted at Massachusetts General Hospital in Boston, where she directs the Tobacco Research and Treatment Unit. “Those trials mostly enrolled people who were pretty healthy,” she said. “They did not include people with depression or much of a history of depression.”
Dr. Rigotti said it was possible that varenicline, the generic name for Chantix, “might have more psychiatric side effects in certain groups of people.”
Continued research should help to resolve lingering concerns about the safety of Chantix. Meanwhile, experts continue to recommend the old standbys: nicotine replacement gums, patches, nasal sprays, inhalers and lozenges, which have been proved to be safe.
Nicotine by itself does not cause cancer, heart disease or other major health problems linked to smoking; other chemicals in tobacco smoke are to blame. Nicotine replacement can be used alone or with prescription medications or, for best results, combined with counseling. Recent evidence suggests that using two forms simultaneously, like the patch and gum together, works better than either alone.
Although nicotine replacement products do not require a prescription, the F.D.A. limits where and how they are sold. They are also expensive.
“It’s so much easier to go down to the corner store and get a pack of cigarettes than it is to get access to evidence-based treatment,” Dr. Fiore said.
This year, the New York State health commission petitioned the F.D.A. to revise its rules so that nicotine gum, patches and lozenges could be sold anyplace that sells cigarettes, and at prices comparable to a cigarette pack. The agency is currently reviewing the petition.
Still, no treatment works for everyone. And even with the most successful treatments, only about 30 percent of attempts to quit last more than six months. Compared with willpower alone, however, that’s a huge improvement. Fewer than one in 10 smokers who go it alone manages to go six months without a cigarette. Most do not make it past a week.
When longtime smokers finally do quit, they soon realize that not smoking doesn’t necessarily make them nonsmokers. That’s what counseling is for — learning to function without nicotine and to cope with the cues that trigger smoking urges.
Most important, former smokers have to rediscover that it is possible to enjoy life without cigarettes, although the yearning may never die completely.
“I’m an ex-smoker,” Dr. Abrams said, “and I still miss it.” said.
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