February 2009
• Is nicotine addictive?
• Properties of nicotine
• Difficulty in quitting
• Nicotine withdrawal
symptoms
• Genetic influence
Nicotine and addiction • Tobacco industry recognition
of the importance of nicotine
Is nicotine
addictive?
In February 2000, the Royal College of Physicians (RCP) published a report
on nicotine addiction which found that nicotine complied with the established
criteria for defining an addictive substance. The report states: “On present
evidence, it is reasonable to conclude that nicotine delivered through tobacco
smoke should be regarded as an addictive drug, and tobacco use as the
means of self-administration.”1
The report noted that: “Cigarettes are highly efficient nicotine delivery devices
and are as addictive as drugs such as heroin or cocaine.”1 Two years earlier,
the report of the Government’s Scientific Committee on Tobacco and Health
(SCOTH) stated that: “Over the past decade there has been increasing
recognition that underlying smoking behaviour and its remarkable
intractability to change is addiction to the drug nicotine. Nicotine has been
shown to have effects on brain dopamine systems similar to those of drugs
such as heroin and cocaine”.2
Both the RCP and SCOTH reports confirmed the findings of the landmark
review by the US Surgeon General in 1988 on nicotine which also concluded
that cigarettes and other forms of tobacco are addicting and that nicotine is
the drug in tobacco that causes addiction.3
Despite these authoritative reviews, there has been some debate about the
extent to which the smoking habit is controlled by physiological addiction.
The debate has arisen because there is no universally accepted definition of
addiction although the World Health Organization has defined addiction as:
“A state, psychic and sometimes also physical, resulting in the interaction
between a living organism and a drug, characterised by behavioural and
other responses that always include a compulsion to take the drug on a
continuous or periodic basis in order to experience its psychic effects, and
sometimes to avoid the discomfort of its absences. Tolerance may or may
not be present.”4 On the basis of this definition, it is possible to demonstrate
a scientific basis for defining nicotine as an addictive substance.
Properties of
nicotine
Nicotine is a stimulant drug, but paradoxically effects of both stimulation and
relaxation may be felt. The mental and physical state of the smoker, and the
situation in which smoking occurs, can influence the way in which a particular
cigarette will affect psychological perceptions.3 The addictive effect of
nicotine is linked to its capacity to trigger the release of dopamine - a
chemical in the brain that is associated with feelings of pleasure.
ASH Fact Sheet: Nicotine and Addiction 1
Properties of
nicotine
(continued)
However, recent research has suggested that in the long term, nicotine
depresses the ability of the brain to experience pleasure.5 Thus, smokers
need greater amounts of the drug to achieve the same levels of satisfaction.
Smoking is therefore a form of self-medication: further smoking alleviates the
withdrawal symptoms which set in soon after the effects of nicotine wear off.
Difficulty in
quitting
Possibly one of the strongest indicators of the effect of nicotine is the
discrepancy between the desire to quit and quitting success rates. Surveys
have shown that the majority of smokers (around 70 per cent) want to stop
smoking6 yet the successful quit rate remains very low.
Twenty per cent or less of those who embark on a course of treatment
succeed in abstaining for as long as a year, while only around 3 per cent
succeed in quitting using willpower alone.7 Most smokers take several
attempts to quit before they finally succeed. The power of addiction is also
demonstrated by the fact that some smokers are reluctant to stop smoking
even after undergoing surgery for smoking-induced diseases. Around forty
per cent of those who have had a laryngectomy try smoking soon afterwards,
while about 50 per cent of lung cancer patients resume smoking after
undergoing surgery.8 Among smokers who have had a heart attack, as
many as 70% take up smoking again with a year. 9
Other
measures of
dependence
There are a number of markers which can measure dependence on a
substance. A key factor is the degree of compulsion to take the drug
experienced by the user. Most smokers smoke on a daily basis. In Britain,
the average self-reported consumption of cigarettes is 14 per day.10 Fewer
than 1 in 20 smokers smoke less frequently than daily. Other indicators of
dependence include the time from waking to first cigarette. In 2007, among
smokers of all ages, 17 per cent reported lighting up within five minutes of
waking. Heavy smokers are much more likely than light smokers to smoke
immediately on waking: 35% of those smoking more than 20 cigarettes a day
compared to just 3% of those smoking fewer than 10 a day. Few smokers
believe that they could manage to go without smoking for a whole day.
Eighty-five percent of smokers who smoke 20 or more cigarettes a day say
that they would find it difficult to go a whole day without smoking.Error! Bookmark
not defined.
Nicotine
withdrawal
symptoms
Another marker for addiction is the occurrence of withdrawal symptoms
following cessation of drug use. For smokers, typical physical symptoms
following cessation or reduction of nicotine intake include craving for nicotine,
irritability, anxiety, difficulty concentrating, restlessness, sleep disturbances,
decreased heart rate, and increased appetite or weight gain. The fact that
these symptoms can be attributed to nicotine, rather than behavioural
aspects of tobacco use is shown by the finding that withdrawal symptoms are
relieved by nicotine replacement therapy (gum, patches, etc.) but not by a
placebo (i.e. products that do not contain nicotine). For further information
about using nicotine as an aid to stopping smoking ASH Fact Sheet: Benefits
and aids to quitting.
Genetic
influence
Recent research suggests that certain smokers may be predisposed to
nicotine addiction through the effects of a gene responsible for metabolising
nicotine.11 Scientists have found that non-smokers are twice as likely to
carry a mutation in a gene that helps to rid the body of nicotine. In addition,
smokers who carry mutations in the gene, (known as CYP2A6) are likely to
smoke less because nicotine is not rapidly removed from the brain and
bloodstream. By contrast, smokers with the efficient version of the gene will
tend to smoke more heavily to compensate for nicotine being removed more
ASH Fact Sheet: Nicotine and Addiction 2
rapidly.
Tobacco
industry
recognition of
the importance
of nicotine
Tobacco industry documents dating from the 1960s have shown that tobacco
companies recognised that the main reason that people continue smoking is
nicotine addiction. A lawyer acting for Brown & Williamson said: “Nicotine is
addictive. We are, then, in the business of selling nicotine, an addictive
drug.”12 Publicly, however, tobacco companies denied that nicotine was
addictive, because such an admission would have undermined their stance
that smoking is a matter of personal choice. As the US Tobacco Institute put
it in 1980: “We can’t defend continued smoking as ‘free choice’ if the person
was ‘addicted’.13 The industry was also quick to realise that selling an
addictive product is good for business: as a British American Tobacco memo
said in 1979: “We also think that consideration should be given to the
hypothesis that the high profits additionally associated with the tobacco
industry are directly related to the fact that the customer is dependent on the
product.”14 In March 1997, Liggett Group, the smallest of the five major US
tobacco companies, became the first to admit that smoking is addictive as
part of a deal to settle legal claims against the company.15 Subsequently the
tobacco companies tried to cast doubt over the meaning of addiction by
comparing smoking with other common pursuits such as shopping or eating
chocolate.16
For further examples of the tobacco industry’s position on addiction see
chapter 2 of ‘Tobacco Explained’. Other examples can be found in “Trust Us,
We’re the Tobacco Industry”
References
1 Nicotine Addiction in Britain. A report of the Tobacco Advisory Group of the Royal College of Physicians, February
2000. [View report]
2 Report of the Scientific Committee on Tobacco and Health. Department of Health, 1998. [View report]
3 The health consequences of smoking. Nicotine Addiction. A report of the Surgeon General. US DHHS, 1988.
4 WHO Technical Report Series no 407, Geneva, 1969.
5 Epping-Jordan, M P et al. Dramatic decreases in brain reward function during nicotine withdrawal. Nature 7 May
1998, p76-79.
6 Smoking-related behaviour and attitudes, 2007. ONS, 2008 View report
7 Smoking cessation guidelines and their cost effectiveness. Thorax 1998; Vol 53 Supplement 5, part 2, S11-S16.
[View report]
8 Stolerman, IP & Jarvis, MJ. The scientific case that nicotine is addictive. Psychopharmacology 1995; 117: 2-10.
9 Stapleton, J. Cigarette smoking prevalence, cessation and relapse. Stat Meth Med Res 1998; 7:187-203
10 Smoking and drinking among adults, 2007. General Household Survey 2007. ONS, 2009. www.statistics.gov.uk/ghs
11 Pianezza ML, Sellers EM and Tyndale RF. Nicotine metabolism defect reduces smoking. Nature 1998; 393: 750.
12 Yeaman, A. Brown & Williamson memo 1802.05, 17/7/63.
13 Tobacco Institute, 9 September 1980. Minnesota trial exhibit 14,303.
14 BAT, Key areas for product innovation over the next ten years. Minnesota Trial Exhibit 11, 283.
15 Usborne, D. Smoking kills: tobacco firm. The Independent, 21/3/98.
16 Proctor, C. BAT Industries - Smoking gun? The Observer, 1/3/98.
ASH Fact Sheet: Nicotine and Addiction 3