Nicotine addiction explained — and how medications can help

A line of single cigarettes falling like dominoes, in the middle of the row, there are wooden tiles spelling out the word Stop

Mark Twain hit on the essence of nicotine addiction when he said, "Giving up smoking is the easiest thing in the world. I know because I've done it thousands of times." While not a formal diagnostic term, addiction refers to loss of control over the use of a substance. For some people and with some drugs, use becomes compulsive and completely uncontrollable. In other cases, like with nicotine, skipping your morning cigarette is more like holding your breath: you can do it for a while, but eventually your reflexes take over.

Because smokers can choose to forego any given cigarette, smoking seems like a habit that can be overcome by willpower, and until recently, addiction was simply considered bad behavior. We now understand that addiction is a neurological disorder that results from changes to the part of the brain referred to as the reward center. Drug use is pleasurable because addictive drugs result in direct stimulation of the reward center, tricking the brain into thinking something great just happened. The pleasurable sensation is the hook that makes people use the drug again and again.

Over time, this kind of stimulation causes neuronal changes, and those changes impact behavior more than we had previously understood. That gets us back to Mark Twain: he could stop using cigarettes for a while, but ultimately his brain led him right back to nicotine, creating an endless loop in which he "gave up" smoking thousands of times, only to find himself smoking again a few days later.

Medication treatment

Addiction is now understood to be a chronic neurological disorder that, like other chronic diseases, responds to treatment. Ideally, management of nicotine addiction combines medications to suppress cravings with counseling to help patients reprogram their behavior, just like treatments for high blood pressure and type 2 diabetes often combine medication with counseling for stress management or behavior change.

The FDA has given varenicline (Chantix) an indication for smoking cessation. It works by blocking and partly activating the nicotine binding spot in the central nervous system, reducing the pleasurable effects of smoking while also reducing withdrawal by releasing dopamine (the chemical that signals brain reward) — though in lower amounts than nicotine. Large studies have found varenicline to be effective and well tolerated: compared to those who received placebo, smokers who received varenicline while trying to quit were more than two and a half times more likely to be cigarette-free one year after entering the trial.

Recently, efforts to help smokers quit were dealt a setback when nine lots of varenicline were recalled because some tablets could contain levels of potential carcinogens called nitrosamines above the acceptable limit set by the FDA. This information is surely of concern to smokers, though given the enormous burden of cigarette smoking on health, the risk-benefit ratio may still be in favor of using medication for people who can successfully quit. Indeed, the FDA has indicated that there is no immediate risk to people taking varenicline and is not recommending that people stop using it, though the recall may result in shortages.

Nicotine replacement medications, such as gums, lozenges, or patches, can also help people quit smoking by relieving symptoms of withdrawal, which are often a major obstacle to quitting. Because oral ingestion and skin absorption of nicotine are slower and result in much lower peak levels than smoking, these forms of nicotine are less rewarding than inhaled nicotine, and can help smokers taper off with fewer withdrawal symptoms and cravings. Bupropion, an antidepressant (brand names Wellbutrin, Zyban, and others), also can help smokers quit by mimicking the effects of nicotine, thus reducing withdrawal symptoms.

Side effects

Of the three medications that are used to help people quit smoking, varenicline is the most effective. Like all medications, it has side effects. These include nausea, insomnia, and headaches. There have been questions as to whether varenicline can cause symptoms of depression, suicidal thoughts, agitation, and aggression, though research suggests that while all of these problems can occur when people try to quit smoking, none of them occur more frequently among people taking varenicline than those assigned placebo. Nonetheless, use should be supervised, and patients who develop mood or behavior changes should notify their physician.

Supportive treatment

Behavioral counseling is a mainstay of treatment for substance use disorders and can help people quit. Quit lines and digital tools are available and can be very helpful, as can individual or group therapy. While optimal treatment combines behavioral counseling with medication, if medications are not available, counseling can be effective on its own. Patients with nicotine addiction can also benefit from health screening to identify and treat medical problems that are caused by smoking, such as breathing issues and heart disease.

Despite the temporary setback in medication availability, campaigns that promote quitting and encourage medication usage may be one of the most logical public health strategies we can deploy. This is especially so for younger smokers, for whom rates of medication usage are exceedingly low.