2013 H Street, NW / Washington,
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As long ago as 1942 there was significant medical evidence that nicotine is an addictive drug. That body of evidence has subsequently grown, and today it is a reasonable medical certainty that nicotine is addictive; so much so that it has been compared to heroin, alcohol and barbiturate addiction. Today, many cigarette smokers are in fact addicts. For this reason ASH has prepared the following summary of some of the more notable research in the area.
Tobacco use is addicting and nicotine is the active pharmacologic agent of tobacco that causes addictive behavior. It also causes physical dependence characterized by a withdrawal syndrome that usually accompanies nicotine abstinence. Evidence about the addictive nature of nicotine has been accumulating since 1942 when a medical researcher first identified the problem. Since that time many medical writers and journals have unequivocally classed smoking, and particularly cigarette-smoking, as an addiction for many people. Some physicians compare the addictive qualities of nicotine to heroin and barbiturates but others maintain that for many people cigarettes can be even more addictive than heroin, barbiturates or alcohol. Comparison can also be made between the use of hard drugs and smoking in various treatment programs and in the relapse rates for such programs. Aveena sativa, a withdrawal aid, has been noted to be somewhat effective in the aversive conditioning of both cigarette and heroin addiction. Apomorphine has been used in the treatment of chronic alcoholism, drug addiction and addiction to cigarettes. As would be expected in addiction, the long-term abstinence rates are not good. One of the factors making nicotine so extremely addictive may be the tolerance which smokers develop. Before he can enjoy inhaling deeply, the novice must acquire a degree of tolerance to the local irritation and autonomic side-effects of nicotine. This is because nicotine is a poison. One-fortieth of a gram of nicotine usually gives rise to toxic symptoms in a nonsmoker. The toxic symptoms consist of excessive "swimminess" (unlike vertigo), rapid and forcible cardiac action, nausea, vomiting and fainting. Once this tolerance has been established, most people smoke to obtain nicotine and are unsatisfied by nicotine-free cigarettes. Smokers unconsciously modify their puff rate to maintain a steady nicotine intake when given high or low nicotine cigarettes. Intravenous nicotine reduces cigarette consumption significantly when compared with a saline control. Nicotine shares with other dependence-producing drugs the quality of acting as a primary reinforcer of behavior.
The 1988 Surgeon General's report, The Health Consequences of Smoking: Nicotine Addiction found that nicotine is a powerful pharmacologic agent that acts in the brain and throughout the body. Nicotine readily crosses the blood-brain barrier and accumulates in the brain shortly after it enters the body. Once in the brain it interacts with specific receptors and alters brain energy metabolism in a pattern consistent with the distribution of specific binding sites for the drug. As a result, effects of nicotine on the central nervous system occur rapidly after a puff of cigarette smoke or after absorption of nicotine from other routes of administration.
There is effective treatment available for the dependent smoker which requires behavioral intervention in addition to any pharmacologic agents that might be administered. Some of the behavioral intervention practices available are rapid smoking, relaxation training, social support and coping skills training. Making the facts about nicotine addiction known may not do much to help the already addicted smokers, but it will encourage more research into the problem of addiction and means to combat it.
At high exposure levels, nicotine is a potent and potentially lethal poison. Human poisonings occur primarily as a result of accidental ingestion or skin contact with nicotine-containing insecticides. Mild nicotine intoxication occurs in first-time smokers, non-smoking workers who harvest tobacco leaves and people who chew excessive amounts of nicotine gum. Tolerance to these effects develops rapidly. Nicotine exposure in long-term tobacco users is substantial, affecting many organ systems. Pharmacologic actions of nicotine may contribute to the pathogenesis of smoking-related diseases. Of particular concern are cardiovascular disease, complications of hypertension, reproductive disorders, cancer, and gastrointestinal disorders, including peptic ulcer disease.
NOTE: This leaflet, which is distributed as a public service, contains general information for your interest. If you have specific medical problems related to smoking you should consult your physician.
2013 H Street, NW / Washington,
DC 20006 / (202) 659-4310