(MONEY Magazine) – If you're among the millions of smokers who resolve to quit each New Year's Day, only to find yourself a few days later dejectedly puffing away, take heart. A revolution in medical understanding of how smokers get hooked has led to new approaches to quitting that can increase your chances of success from the 5% typical of cold-turkey quitters to 20% or more. And at least part of the $206 billion tobacco settlement will go to funding programs to help you.

Recent studies provide clues to why breaking an addiction to nicotine is so difficult--even more difficult than kicking heroin or cocaine, according to Steven Adelman, medical director of substance abuse services for Harvard Vanguard Medical Associates. Nicotine stimulates brain cells to release a pleasure-inducing chemical called dopamine. "Each puff of a cigarette is a hit, a neurobiological mini-orgasm that is repeated millions of times, which explains why smokers yearn for that experience much longer than people addicted to many other pleasure-giving substances," Adelman says.

To still quitters' cravings, doctors and counselors have come to rely on various forms of nicotine replacement--from the now familiar skin patches to the cigarette-like Nicotrol Inhaler introduced last year. And the new drug Zyban targets the pathways of nicotine addiction in the brain, rather than replacing nicotine. The table at right details the cost, side effects and percentages of smokers who are still off cigarettes a year after quitting while using each of these products. Although you may see ads touting a product's success among those who've used it for a month or two, the one-year success rate is the best indicator of effectiveness, says Richard Merrick, whose 10-week smoking-cessation program at Kaiser Permanente in Harbor City, Calif. has an astounding 57% one-year quit rate.

How Zyban helps

Richard E. Hurt, director of the Mayo Clinic's $3,000 eight-day inpatient program, which has helped 43% of its severely addicted clients kick the habit, generally recommends that smokers start taking Zyban--the first pill to be approved by the FDA as a smoking-cessation aid--about a week before they plan to quit.

The drug, which is also sold as an antidepressant called Wellbutrin SR (the initials stand for sustained release), lessens the desire to smoke by raising dopamine levels in the brain, just as cigarettes do. Zyban also whittles the average quitter's five-pound weight gain.

Zyban has no effect on 15% to 20% of smokers who try it, says Linda Ferry, a researcher at Loma Linda University School of Medicine, who first discovered that the drug helped people quit smoking. Experts suggest giving Zyban a one-month trial; most people take it for 12 weeks. Some health plans don't cover Zyban, but a few less than forthcoming smokers have gotten around that by asking doctors to diagnose them with depression and prescribe Wellbutrin SR, which is generally covered.

Because Zyban carries a slight (one in 1,000) risk of seizures, Harvard Vanguard's Adelman prefers starting patients off with a nicotine patch. But for smokers who find they crave the ritual and hand-to-mouth activity of smoking, nicotine gum, the inhaler or nasal spray may work better, he says. The nasal spray gets nicotine into your system fastest, while the inhaler most closely replicates the act of smoking. The gum's advantage is that it's available without a prescription; most smokers will need the 4mg version.

To help the most intractable smokers, specialists now combine Zyban with nicotine-replacement products, using double patches or patches plus gum or an inhaler. "Most patches deliver only half the nicotine a smoker would get from one pack a day. So some may find nicotine replacement hasn't worked well simply because they're being underdosed," says the Mayo Clinic's Hurt. Some doctors keep patients on the products for several months rather than the 10 to 12 weeks most manufacturers recommend.

But to avoid dangerously high blood pressure or nicotine overdosing (40mg to 60mg is considered lethal, but individual tolerances can vary), combining products or straying from dosage instructions should be done only under a doctor's supervision. And while nicotine replacement is safer than smoking, new studies from the University of Minnesota suggest that using nicotine replacement for more than three to six months may damage blood and lung cells, possibly leading to artery disease, bronchitis or both.

Why you may need a support group

"Smoking is a way of coping with stress as well as of obtaining pleasure, so breaking that psychological addiction is just as crucial as eliminating the physical one," says Bonnie Spring, a University of Illinois-Chicago psychologist whose programs achieve long-term quit rates of 40% or more. Adding some form of counseling to your quitting plan is essential, says Richard Merrick. Participants in his highly successful Kaiser Permanente program attend Nicotine Anonymous meetings (415-750-0328). Merrick says that the group, which applies Alcoholics Anonymous principles to smokers, is the best of the many low-cost or free groups because it offers long-term support. If Nicotine Anonymous doesn't meet in your area, both the American Cancer Society (800-227-2345) and the American Lung Association (800-586-4872) sponsor counseling programs of four to eight weeks' duration.

What's coming

In the research pipeline now are several drugs that, like Zyban, target brain chemistry. There are also novel forms of nicotine replacement, including an under-the-tongue tablet and a lollipop. The market for these drugs is expanding at a rapid pace. In 1998, sales of over-the-counter nicotine-replacement products exceeded $568 million, according to Information Resources, a Chicago-based marketing research firm. That's nearly double total sales in 1996, when these products first became available over the counter. Prescriptions are soaring too. Sales for the 12 months that ended September 1998 totaled $184.4 million, up 154% from the previous year, according to IMS Health, a health-care information company in Plymouth Meeting, Pa.

Using smoking-cessation aids as part of a plan you develop with an experienced doctor makes you more likely to reap their full benefits. First, though, talk to your health plan. About 75% of HMOs now cover smoking-cessation products and programs, which may be provided by the plan itself. You can also locate a physician who specializes in smoking cessation by calling the 3,200-member American Society of Addiction Medicine (301-656-3920).