Scientific Activities - Actividades Científicas
Honorary Committee Lecture
The power of addiction
Published in ProCOR
Bernard Lown, MD
Awarded with Nobel Prize
The power of addiction
The annual reports issued by the Surgeon General of the USA bring together encyclopedic data on the adverse health effects of smoking. These have great credibility and have never been challenged by the tobacco companies. Since the initial report in 1964, a veritable Niagara of information has deluged the public with the dangers of tobacco, yet 50 million Americans still continue to smoke. Surveys document that people recognize the health hazards. In 1985 a Gallop poll found that 90% of smokers were aware that smoking could lead to heart disease and cancer.(1) If people know the facts why don't they quit? The answer is that they try. Two fifths of all current smokers indicate that they had made three or more serious attempts to quit.(2) Among former male or female smokers, three or more attempts were required before they succeeded.
The intractability of the habit was brought home to me by a patient with severe congestive heart failure whom I had treated for more than a decade. Throughout this long period, I failed to persuade him to give up smoking. During his terminal illness, he was painfully gasping for breath while puffing on a cigarette sticking out from a tracheostomy tube. For the cigarette smoker the desire to smoke appears irresistible, nearly half will continue to smoke even after having a cancerous lung removed. About 80% of smokers say they want to kick the habit, but each year fewer than one in ten succeed.(3)
Smoking is no longer presumed to be an innocuous social habit, but rather a noxious and powerful chemical dependency. The addictiveness of nicotine is recognized by the American Psychiatric Association, the American Medical Association, the US Surgeon General, the World Health Organization, the Medical Research Council of the United Kingdom, and a host of others.(4) Internal tobacco company documents indicate that the addictive power of tobacco was well known. More than three decades ago, the general counsel of one of the large tobacco companies acknowledged, "We are in the business of selling nicotine, an addictive drug." (5) Cigarettes are a highly engineered product with the components such as the tobacco blend, the filter, and the ventilation system carefully designed to deliver controlled pharmacologically active doses of nicotine.(4) Cigarettes are essentially nicotine delivery systems.
Few who smoke regularly for a year can quit easily. Nicotine is believed to be the main addictive compound in cigarette smoke and reaches the brain within ten seconds, providing an immediate high. Unlike other addictive psychoactive substances, the pleasurable effects last no longer than the lighted cigarette. The flavor of the cigarette, having been associated with nicotine, may also be addictive. The smoker is not after the psychoactive effect, but like a chocaholic, craves the taste of the cigarette. After quitting, the duration of withdrawal may be as short as a few days, for most it is closer to a month. Some of my former smoking patients pined for a cigarette for more than a year or longer, the craving was most insistent following a big meal.
The dependence on cigarettes is similar to other addictive drugs. When 1000 persons seeking treatment for alcohol or drug dependence were questioned about the difficulty of quitting smoking, 74% reported that cigarettes would be as hard to give up as their substance problem, while a majority, 57%, indicated that giving up smoking would be more difficult.(6) Overall comparative ratings of problem substances and smoking indicate that, while cigarettes provide less pleasure, the urge for smoking is greater than for other addictive drugs.
Nicotine meets the key criteria for addiction or dependence used by major medical organizations. Smokers show the three basic signs of addiction: they become dependent; they become tolerant and quitting is associated with physical withdrawal symptoms, including headache, insomnia, depression, constipation, inability to concentrate and anxiety. According to testimony from the National Institute of Drug Abuse, gram for gram nicotine is five to 10 times more effective in producing mood changes than amphetamines which pharmacologically have very similar actions to cocaine.(7) The effects of nicotine on the brain are complex, depending on circumstances and dose. It may serve both to tranquilize as well as to stimulate mood and brain activity.(8, 9)
The addictiveness of nicotine probably relates to the activation of dopaminergic neurons in the mesolimbic system, the very pathways which govern the intense craving for food, drink or sex and is similar to the brain centers activated by cocaine. Nicotine injected into rats doubles the level of dopamine in the mesolimbic system. Rats addicted to nicotine no longer seek it when these mesolimbic nerve fibers are destroyed or dopamine action is blocked.(3) With continuous nicotine administration, rats do not increase dopamine release. In man likewise, plasma nicotine levels in smokers rise during the day to a point when receptors become desensitized and the pleasant sensation provided by smoking is lost. Receptor attenuation may account for the fact that some smokers find the first cigarette of the day the most gratifying.
Whether a person becomes addicted may also depend on genetic makeup. The best studied addictive substance is alcohol wherein much evidence suggests operation of a a genetic factor. Children of alcoholics are less sensitive to the intoxicating effects of alcohol than are children of non-alcoholics. (10) Carmelli and coworkers(11) examined hereditary influences on smoking in a large sample of twins who served in the armed forces during World War II. They found a moderate genetic influence on the initiation and maintenance of smoking, as well as on the level of dependence and on the inability to quit.
Drug addiction is a complex process involving the interplay between pharmacology of a psychoactive substance, family and peer influences, personality, existing psychiatric disorders, the cost and availability of the drug, the influence of advertising, and a host of other factors. For example, many patients with heart or lung disease, especially women, refuse to abandon cigarettes because of experiencing significant weight gain once they give up smoking. Ample evidence supports the fact that smoking tames appetite for food.(12)
The tobacco companies have long claimed that their aim was to provide sensory pleasure, not to satisfy an addiction. They argued that smokers have had ample warnings of the danger of cigarettes and have only themselves to blame for their behavior. The identification of nicotine as an addictive substance calls into question traditional assumptions about the "voluntary" and informed nature of cigarette smoking. The evidence now being amassed is that hapless customers are being deliberately addicted.(4) According to the Food and Drug Administration (FDA), tobacco companies tailor the manufacture of cigarettes to deliver precise doses of nicotine to maximize addiction and minimize consumer attrition. A frequent practice in tobacco blending is to raise the nicotine concentration in low-tar cigarettes. In testimony before a Congressional Committee, Dr. David A. Kessler, former director of the FDA, reported that the Brown and Williamson Tobacco Company, a US subsidiary of London based BAT industries had secretly developed a superpotent tobacco hybrid in Brazil called Y-1, that contains nearly twice the amount of nicotine found in standard flue-cured tobacco. The hybrid was used to boost the nicotine content of five domestic brands. (13) Dr. Kessler also charged that a common technique employed for enhancing nicotine delivery in low tar cigarettes is the use of a filter and ventilation system that by design remove a higher percentage of tar than nicotine. Another manipulation is the addition of ammonia compounds that increase the delivery of free nicotine to smokers by raising the alkalinity of tobacco smoke.(4) The New York Times, in response to such testimony, editorially accused the tobacco companies of, "cynically addicting millions of customers in a crime of unconscionable dimensions."(7)
The marketplace for tobacco products is sustained by the addiction to nicotine and is spurred by prodigious investments in advertisement and promotion techniques aimed at gullible young people. According to Schelling,(2) compared to other addictive drugs, cigarettes are cheap. At the current federal minimum wage, the cost of a package is equivalent to about 20 minutes of work. They are universally available. "It requires no equipment other than a match. They are easily portable require no special storage. There is no fear of overdose. It could be done everywhere alone and in company. Do not impair any faculties. There is no intoxication, no slurring of speech or loss of balance, no loss of visual acuity. No social norms governed where smoking was permissible or where it was proscribed. Smoking was never impolite. It was something to be shared with friends. Smoking is something that every smoker is good at. Smoking is socially facilitating activity." (2) Sixteen year old boys and girls feel invincible. To be told that some forty years later smoking may undermine their health or shorten their lives is completely unfazing. The tobacco companies are well aware that addicting teenagers assures life long customers.
Governments in the industrialized countries have taken a benign view of the magnitude of the mayhem wrought by this pernicious addiction. The US government invests multibillion dollars annually to interdict other addicting drugs and metes out stiff prison sentences for those who sell these substances. No such rigorous campaign has ever been waged against tobacco merchandisers. While annually in the USA 6,000 to 7,000 die from heroin and cocaine, the estimated lives clamed from smoking related illness exceed 400,000. Smoking kills more people than AIDS, car accidents, alcohol, homicide, all other addicting drugs, suicides and fires combined.(14) Indeed cigarettes are among the most addictive substances of abuse and by far the most deadly.Top
1. A 1985 Gallop Poll, "Survey of attitudes toward
smoking" American Lung Association News, 5 December 1985.
2. Schelling T. Addictive drugs: The cigarette experience. Science 1992 January 24;255:430.
3. Nowak R. Nicotine scrutinized as FDA seeks to regulate cigarettes. Science 1994;263:1555.
4. Kessler D A, et al. The legal and scientific basis for FDA
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11. Carmelli D, Swan GE, Robinette D et al. Genetic influence on smoking
12. US Dept of Helath and Human Services, Office of Smoking and Helath . The Health Consequences of smoking. Nicotine Addiction . A Rport of the US Surgeon General Washington DC : US Government Printing Office 1988:7-8. 270:334.
13. McCarthy M Attack and counterattack in US tobacco war Science 1994; 344:49.
14. Kessler DA. Nicotine addiction in young people . Sounding Board. N Eng J Med 1995:333:186.