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  » Smoking and health effect  »  What makes tobacco addictive?
Is nicotine a drug of addiction?
  • Nicotine obtained from cigarettes meets all the standard criteria used to define a drug of dependence or addiction
  • Historically, and in contrast to addiction to opiates or alcohol, addiction to nicotine has not been recognised as a medical or social problem in Britain
  • Nicotine is highly addictive, to a degree similar or in some respects exceeding addiction to ‘hard’ drugs such as heroin or cocaine
  • Most smokers do not smoke out of choice, but because they are addicted to nicotine

What makes nicotine addictive?

In 1988 the U.S. Surgeon General concluded that nicotine in tobacco is addictive. 1 The three major findings were:

  • cigarette smoking and other forms of tobacco use are addictive
  • nicotine is the drug in tobacco that causes addiction
  • nicotine addiction is similar to heroin or cocaine addiction.

How nicotine works

  • Nicotine causes chemical or biological changes in the brain. This effect is called psychoactive and although it is less dramatic than heroin or cocaine, the strength of the addiction is just as powerful. It is a 'reinforcing' drug, which means that users desire the drug regardless of the damaging effects. For example, in research conducted in 1994, only 50% of smokers who suffered a heart attack managed to quit smoking even though their doctors advised them to. Coincidentally, 50% of all regular smokers die as a result of smoking.
  • Nicotine addiction is a physical dependency. Withdrawal symptoms are severe and most smokers cannot quit on their first attempt because of these symptoms.
  • The human body builds a tolerance to nicotine and the effect of the drug is reduced over time. As a result, regular smokers can inhale greater amounts of smoke and therefore greater amounts of toxins, without showing immediate effects (ie coughing, nausea).
  • Nicotine is extremely poisonous if consumed in large amounts and most people feel sick and dizzy the first time they smoke. These negative affects are quickly overcome. Over time the body builds a tolerance to nicotine, resulting in an increase in the amount of cigarettes smoked.

Nicotine in the body

  • Cigarette smoke is acidic and therefore nicotine is absorbed through the lungs. Pipe and cigar smoke is alkaline and the nicotine is absorbed through the mouth. Human lungs are very efficient in absorbing nicotine which then moves through the bloodstream and into the brain and other organs of the body.
  • It takes only 10 seconds for nicotine to reach the brain after being inhaled. This causes several physiological reactions
  • Acute increase in heart rate and blood pressure
  • Constriction of blood vessels causing a temperature drop in the hands and feet
  • Brain waves are altered and muscles relax.

Levels of dependency

  • Levels of dependency vary, but 89% of smokers have a cigarette every one to two hours throughout the day.
  • A highly addicted smoker smokes more than 25 cigarettes a day, ranks the first cigarette in the day as the most important, and will smoke within 30 minutes of waking up.

Withdrawal symptoms

  • The most severe withdrawal symptoms occur within the first week although the craving for cigarettes usually persists for months and even years. The desire to smoke tends to be especially strong when a person is under stress. The typical withdrawal symptoms are:
    • headaches
    • anxiety and irritability
    • difficulty concentrating and sleeping
    • hunger
    • decreased heart rate and blood pressure
    • craving for nicotine.
  • Other side-effects, such as tiredness and coughing, are indications that the body is in a state of repair and is cleaning out the poisons associated with smoking.
  • According to the U.S. Lung Health Study, weight gain for men averaged 4.9 kg and 5.2 kg. for women in the first year after quitting.

Quitting smoking

  • There are now more former smokers (26%), over the age of 15, than current smokers (25%).
  • The most common reason given for quitting smoking is concern about future personal health. Other reasons for quitting were life-style changes, cost of cigarettes, having a baby, and smoke-related illness or death of a friend or family member.
  • The most common reason current smokers give for not quitting is lack of will-power.

There are five successive stages to quitting smoking:

  • Pre-contemplation -- not thinking about quitting
  • Contemplation -- thinking about quitting but not yet ready
  • Preparation -- getting ready to quit
  • Action -- quitting
  • Maintenance -- remaining a non-smoker.


  1. US Department of Health and Human Services. The Health Consequences Of Smoking: Nicotine Addiction. A report Of The Surgeon General. Rockville, Maryland: Public Health Service, Centers for Disease Control, Center for Health Promotion and Education, Office in Smoking and Health, 1988.
  2. Zevin S, Gourlay SG, Benowitz NL. Clinical Pharmacology Of Nicotine. Clinics in Dermatology. 1998;16: 557-564.
  3. Lynch B, Bonnie R (Eds). Growing Up Tobacco Free; Preventing Nicotine Addiction In Children And Youth. Committee on Preventing Nicotine Addiction in Children and Youth, Division of Biobehavioural Sciences and Mental Disorders, Institute of Medicine, National Academy Press, Washington DC, 1994.
  4. Doll R, Peto R, Wheatley K, Gray R, Sutherland I. Mortality In Relation To Smoking: 40 Years' Observations On Male British Doctors. British Medical Journal. 1994;309:901-11.
  5. Schiffman S. Tobacco "Chippers" - Individual Differences In Tobacco Dependence. Psychopharmacology. 1989;97:539-537.
  6. Benowitz NL. Pharmacologic Aspects Of Cigarette Smoking And Nicotine Addiction. New England Journal of Medicine. 1988;319:1318 -1330.
  7. O'Hara P, Connett J.E. Lee WW, Nides M, Murray R, Wise R. Early And Late Weight Gain Following Smoking Cessation In The Lung Health Study. American Journal of Epidemiology. 1998;148(9): 821-830.
  8. Ellison LF, Morrison HI, de Groh M, Villenueve PJ. Health Consequences Of Smoking Among Canadian Smokers: An Update. Chronic Diseases in Canada. 1999; 20(1).
  9. Health Canada. Government Tobacco Control Interventions. CTUMS (Canadian Tobacco Use Monitoring Survey), Wave 1, February-June 1999.

Is the addiction purely chemical?

No. While changes in brain and body chemistry are a big part of addiction, they don't tell the whole story. Smoking is also a learned behaviour. For example, over a one-year period a one-pack a day smoker will take a puff more than 70,000 times. We begin to learn or associate things such as the way we hold or light a cigarette or take it out of the package with the pleasant feelings or sense of relief that it brings us.

We also learn to associate having a cigarette with other things we do immediately before or after smoking such as drinking coffee, alcohol, or eating a good meal. Because smoking often requires us to take a break from our daily duties, we may also learn to associate smoking with the temporary relief of worry, tension, boredom or fatigue. We may also associate smoking with having a good time with friends.

The good news is, with practice and preparation we can break old behavioural habits and learn new ways of getting the benefits we associate with smoking.

How long does it take to become addicted?

Scientists don't really know how long it takes to become addicted. Some say the process begins after only a few cigarettes while others believe it may take a few months or even years after starting to smoke. It probably varies from person to person and depends on how much you smoke or use other forms of tobacco. For example, some people have certain genes that make them more susceptible to nicotine addiction. It may also depend upon whether your mother smoked during pregnancy.

Does everyone who uses tobacco become addicted?

No, not everyone who smokes will develop what doctors call "nicotine dependency". The most recent estimates from the United States suggest that about half of daily smokers have a nicotine dependency. The rate of dependency among occasional smokers is very low.

How do I know if I'm addicted to nicotine?

Different people have different levels of addiction. However, the more you smoke, the more likely you are to be addicted. Persons who smoke less than 10 cigarettes a day are less likely to be addicted. Smoking an average of more than 25 cigarettes a day is a strong indication of addiction.

The sooner you have to smoke after getting out of bed, the more likely you are addicted. People with moderate to high levels of addiction smoke within 30 minutes of getting up. You may be addicted if going without a cigarette for more than a few hours causes you to experience moderate to severe withdrawal symptoms.

Finally, you may be addicted if you have made several serious attempts to quit but have been unable to stay smokefree for more than a couple of days. The more of these situations that are true of you, the more likely it is that you are dependent on nicotine.