Addiction and Withdrawal

Billions of dollars have been spent in the United States fighting over whether or not nicotine is addictive. The position of the medical and scientific communities is that nicotine is most definitely addictive. Nicotine meets both the psychological and physiological measures of addiction:

• Psychological - People who are addicted to something will use it compulsively, without regard for its negative effects on their health or their life. A good example would be someone who continues to smoke, even as they use an oxygen tank to breathe because of the damage smoking has done to their lungs.

• Physiological - Neuroscientists call anything that turns on the reward pathway in the brain addictive. Because stimulating this neural circuitry makes you feel so good, you will continue to do it again and again to get those feelings back.

Nicotine's effects are short-lived, lasting only 40 minutes to a couple of hours. This leads people to smoke or chew tobacco periodically throughout the day to dose themselves with nicotine. Add to this the fact that you can become tolerant to nicotine's effects -- you need to use more and more nicotine to reach the same degree of stimulation or relaxation -- and you can see how people would quickly move from smoking one cigarette to a pack a day habit.

What happens when smokers abruptly stop using nicotine? While you're using nicotine-containing products, your body adapts the way it works to compensate for the effects of the nicotine. For example, neurons in your brain might increase or decrease the number of receptors or the amount of different neurotransmitters affected by the presence of nicotine. When you no longer have nicotine in your body, these physiological adaptations for nicotine remain. The net result is that your body can't function the same way in the absence of the drug as it did before, at least in the short term. People trying to quit nicotine experience this as:

• Irritability
• Anxiety
• Depression
• Craving for nicotine

Over a period of about a month, these symptoms and the physiological changes subside. But for many smokers, even a day without nicotine is excruciating. Every year, millions of people try to break the nicotine habit; only 10 percent of them succeed. Most people throw in the towel after less than a week of trying, because the way that nicotine rewires the reward system in the brain makes nicotine's pull irresistible.