Nicotine-the component of tobacco that causes addiction-is one of the most heavily used addictive drugs in the United States. Smoking cigarettes is the most popular method of taking in nicotine; other methods include smoking cigars and pipes and chewing tobacco.
Effects of Nicotine
When a person inhales tobacco smoke (from a cigarette, pipe, or cigar) the nicotine in the smoke is rapidly absorbed into the blood and affects the brain within a few seconds. Nicotine is also quickly absorbed from chewing tobacco. Nicotine acts as both a stimulant and a depressant to the central nervous system. Nicotine first causes a release of the hormone epinephrine, which further stimulates the nervous system and is responsible for part of the "kick" from nicotine-the drug-induced feelings of pleasure and, over time, addiction. Nicotine also promotes the release of the hormone beta-endorphin, which inhibits pain. This stimulation is then replaced with a drop in mood and fatigue, which lead the smoker to seek more nicotine. This cycle leads to chronic tobacco use and addiction.
In the cardiovascular system, nicotine increases heart rate and blood pressure and restricts blood flow to the heart muscle. In addition to nicotine, cigarette smoke contains more than 4,000 substances, many of which may cause cancer or damage the lungs. Cigarette smoking is associated with many health problems, including:
- Chronic bronchitis
- Lung cancer
- Many other cancers:
- Coronary heart disease
Women who smoke while taking oral contraceptives are at increased risk for cardiovascular and cerebrovascular diseases; this risk is even greater after age 30. Women who smoke cigarettes have earlier menopause. Pregnant women who smoke run an increased risk of having stillborn or premature infants or infants with low birth weight. Children of women who smoked while pregnant have an increased risk for developing conduct disorders.
Although cigar and pipe smokers have lower death rates than cigarette smokers do, they are still susceptible to cancers of the oral cavity, larynx, and esophagus. Users of chewing tobacco and snuff have an elevated risk for oral cancer.
People addicted to nicotine experience withdrawal when they stop smoking. This withdrawal involves symptoms such as:
- Anger, hostility, and aggression
- Difficulty dealing with stress
- Depressed mood
- Difficulty concentrating
- Increased appetite
- Craving for nicotine
Most of these symptoms subside within three to four weeks, except for the craving and hunger, which may persist for months.
Addiction to nicotine is a chronic, relapsing disorder. It may take a smoker several attempts at quitting before he or she is able to permanently give up smoking. The least withdrawal symptoms and greatest success comes with using some type of intervention and gradually reducing the use of nicotine, rather than quitting all at once (going "cold turkey"). Rates of relapse are highest in the first few weeks and months and drop considerably after 3 months. Interventions that involve both medications and behavioral treatments appear to be the most successful.
Nicotine replacement therapy is the primary medication therapy currently used to treat nicotine addiction. These products include gum, a patch, sprays, and inhalers. Nicotine replacement products supply enough nicotine to prevent withdrawal symptoms and therefore prevent relapse while the smoker is undergoing behavioral treatment to help break his or her addiction to nicotine. All types of nicotine replacement products are about equally effective, roughly doubling the chances of successfully quitting.
Another medication approved by the Food and Drug Administration to help quit smoking is the antidepressant bupropion (Zyban). This drug helps control nicotine cravings in people trying to quit. The association between nicotine addiction and depression is not yet understood, but nicotine appears to have an antidepressant effect in some smokers. Paradoxically, though, buproprion is more effective for treating nicotine addiction in nondepressed smokers than in smokers who are depressed.
Behavioral treatment includes psychological support and skills training to overcome high-risk situations. For example, alternative rewards and reinforces can reduce cigarette use. One study found that the greatest reductions in cigarette use were achieved when smoking cost was increased in combination with the presence of alternative recreational activities.
Sourced from: Karen Schroeder, MS, RD, "Nicotine and Tobacco Products"