Fast Facts - Nicotine - Tobacco - Cigarettes
Nicotine is one of the most heavily used addictive drugs in Canada. Cigarette smoking has been the most popular method of taking nicotine since the beginning of the 20th century. In 1998, 28 percent of all Canadians aged 12 and older were current cigarette smokers. Cigarettes and other forms of tobacco, such as cigars, pipe tobacco, and chewing tobacco, are considered to be addictive and nicotine is the drug in tobacco that causes addiction. Also, smoking is a major cause of stroke and the third leading cause of death in Canada.
For many years young children were exposed to seeing cigarettes, such as the fake (candy) cigarettes, in the image on the right. Thus, when children grew older and tried real cigarettes for the first time - they had already practiced puffing, and did not see them as dangerous.
Nicotine is highly addictive and dangerous. It is both a stimulant and a sedative to the central nervous system. The ingestion of nicotine results in an almost immediate “kick” because it causes a discharge of epinephrine from the adrenal cortex. This stimulates the central nervous system, and other endocrine glands, which causes a sudden release of glucose. Stimulation is then followed by depression and fatigue, leading the abuser to seek more nicotine. Nicotine is absorbed readily from tobacco smoke in the lungs, and it does not matter whether the tobacco smoke is from cigarettes, cigars, or pipes. Nicotine also is absorbed readily when tobacco is chewed. With regular use of tobacco, levels of nicotine accumulate in the body during the day and persist overnight. Thus, daily smokers or chewers are exposed to the effects of nicotine for 24 hours each day. Nicotine taken in by cigarette or cigar smoking takes only seconds to reach the brain but has a direct effect on the body for up to 30 minutes.
Research has shown that stress and anxiety affect nicotine tolerance and dependence. The stress hormone corticosterone reduces the effects of nicotine; therefore, more nicotine must be consumed to achieve the same effect. This increases tolerance to nicotine and leads to increased dependence. Addiction to nicotine results in withdrawal symptoms when a person tries to stop smoking. For example, a study found that when chronic smokers were deprived of cigarettes for 24 hours, they had increased anger, hostility, and aggression, and loss of social cooperation. Persons suffering from withdrawal also take longer to regain emotional equilibrium following stress. During periods of abstinence and/or craving, smokers have shown impairment across a wide range of psychomotor and cognitive functions, such as language comprehension.
If women smoke cigarettes and also take oral contraceptives, they are more prone to cardiovascular and cerebrovascular diseases than are other smokers; this is especially true for women older than 30. Pregnant women who smoke cigarettes 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. National studies of mothers and daughters have also found that maternal smoking during pregnancy increased the probability that female children would smoke and would persist in smoking.
In addition to nicotine, cigarette smoke is primarily composed of a dozen gases (mainly carbon monoxide) and tar. The tar in a cigarette, which varies from about 15 mg for a regular cigarette to 7 mg in a low-tar cigarette, exposes the user to a high expectancy rate of lung cancer, emphysema, and bronchial disorders. The carbon monoxide in the smoke increases the chance of cardiovascular diseases.
Secondhand smoke can also cause lung cancer in adults and greatly increases the risk of respiratory illnesses in children and sudden infant death.
Research has shown that nicotine, like cocaine, heroin, and marijuana, increases the level of the neurotransmitter dopamine, which affects the brain pathways that control reward and pleasure. Scientists now have pinpointed a particular molecule (the beta 2 subunit of the nicotine cholinergic receptor) as a critical component in nicotine addiction.
Other new research found that individuals have greater resistance to nicotine addiction if they have a genetic variant that decreases the function of the enzyme CYP2A6. The decrease in CYP2A6 slows the breakdown of nicotine and protects individuals against nicotine addiction.
Another study found dramatic changes in the brain's pleasure circuits during withdrawal from chronic nicotine use. These changes are comparable in magnitude and duration to similar changes observed during the withdrawal from other abused drugs such as cocaine, opiates, amphetamines, and alcohol. Scientists found significant decreases in brain sensitivity to pleasurable stimulation after nicotine administration was abruptly stopped. These changes lasted several days and may correspond to the anxiety and depression experienced by humans for several days after quitting smoking “cold turkey.”
Research suggests that smoking cessation should be a gradual process because withdrawal symptoms are less severe in those who quit gradually than in those who quit all at once. Rates of relapse are highest in the first few weeks and months and diminish considerably after 3 months. Studies have shown that pharmacological treatment combined with psychological treatment, including psychological support and skills training to overcome high-risk situations, results in some of the highest long-term abstinence rates. Behavioral economic studies find that alternative rewards and reinforcers 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. Nicotine chewing gum is one medication approved for the treatment of nicotine dependence. Nicotine in this form acts as a nicotine replacement to help smokers quit the smoking habit. The success rates for smoking cessation treatment with nicotine chewing gum vary considerably across studies, but evidence suggests that it is a safe means of facilitating smoking cessation if chewed according to instructions and restricted to patients who are under medical supervision.
Another approach to smoking cessation is the nicotine transdermal patch, a skin patch that delivers a relatively constant amount of nicotine to the person wearing it. Both nicotine gum and the nicotine patch, as well as other nicotine replacements such as sprays and inhalers, are used to help people fully quit smoking by reducing withdrawal symptoms and preventing relapse while undergoing behavioral treatment. Another tool in treating nicotine addiction is a medication that goes by the trademark Zyban®. This is not a nicotine replacement, as are the gum and patch. Rather, this works on other areas of the brain, and its effectiveness is in helping to make controllable nicotine craving or thoughts about cigarette use in people trying to quit. In the future, a nicotine vaccine may be an effective method for preventing and treating tobacco addiction. The vaccine would prevent nicotine from reaching the brain so as to reduce its effects and help keep people from becoming addicted.
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