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4 Is nicotine a drug of addiction?

*4.1 The definition of addiction and dependence
*4.2 Does nicotine use through smoking meet standard diagnostic criteria for addiction?
*4.3 The history of social, cultural and political responses to nicotine addiction in Britain
*4.4 How does nicotine addiction compare with addiction to other drugs?
*4.5 Relevance to society of recognition of nicotine as an addictive drug
*References

4.1 The definition of addiction and dependence

'Addiction' and 'dependence' are terms whose definition has a social as well as a scientific dimension. In principle, they may be distinguished, but in practice such a distinction serves little purpose and the terms are used interchangeably here. They are socially and scientifically defined in that their meaning can be, and has been, changed to reflect changing perceptions rather than to identify unequivocally an invariant, objectively definable entity. Under the current definition, the terms refer to a situation in which a drug or stimulus has unreasonably come to control behaviour.1,2

This definition is very different from that used in the past and to which the general public mostly subscribe.3 This earlier and popular view is that addiction refers to a state in which an individual needs to continue to take a drug in order to stave off unpleasant or dangerous withdrawal effects. The main shortcoming of this approach to defining addiction is that it addresses just one aspect of a wider problem. Certainly, many drug addicts experience withdrawal discomfort when they abstain, and this provides an important motive for continuing to use the drug. However, it has also long been recognised that this motive plays a relatively modest role in the apparently unreasonable continued use of a drug, despite protestations of users that they want to stop, and despite the harm their drug use is doing both to them and to those around them. Individuals given morphine for pain relief may experience withdrawal symptoms when it is withdrawn but do not become compulsive users, yet individuals attempting to stop using drugs, including nicotine, continue to relapse at a high rate long after withdrawal symptoms have resolved. Moreover, controlling withdrawal symptoms alone is not necessarily sufficient to prevent relapse to drug use.4

Another outmoded feature of the definition of addiction is inclusion of the concept of intoxication.3 Under this view, addictive drugs lead to changes in users' psychological state, leaving some degree of impairment. This feature no longer appears in any official definition because it is apparent that it is neither a necessary nor a sufficient condition for compulsive, harmful drug seeking.5 Many cannabis and alcohol users become intoxicated but do not develop dependence, while cocaine and amphetamine use can be compulsive without performance being noticeably impaired. Definitions of dependence or addiction to drugs in general have had to develop and evolve over time to take account of changes in these and other relevant concepts.
Three of the most widely used generic criteria for substance dependence are summarised in Table 4.1. These comprise the American Psychiatric Association (APA) Diagnostic and Statistical Manual of Mental Disorders (DSM)-IIIR criteria,6 the DSM-IV criteria7 (which superseded DSM-IIIR in 1995), and the World Health Organization International Classification of Diseases (ICD)-10 criteria.2 The APA criteria are generally much more detailed than ICD-10, but share common concepts of difficulty in controlling the use of the drug, of giving priority to drug use over other important obligations, to continued use of the drug in the knowledge of harmful consequences, and tolerance to the effects of the drug. The criteria are designed to apply generically to substance abuse, but provide a suitable framework for determining the addictive or dependent nature of nicotine and smoking.

Table 4.1. Summary of Diagnostic and Statistical Manual of Mental Disorders (DSM-IIIR), DSM-IV and International Classification of Diseases (ICD)-10 criteria for substance dependence.
DSM-IIIR DSM-IV ICD-10
At least 3 of: At least 3 of: A cluster of behavioural, cognitive and physiological phenomena that develop after repeated substance use and that typically include:
Substance often taken in larger amounts or over a longer period than intended Substance often taken in larger amounts or over a longer period than intended A strong desire to take the drug
Persistent desire or one or more unsuccessful efforts to cut down or control use Persistent desire or unsuccessful efforts to cut down or control use Difficulty controlling use
A great deal of time spent in activities necessary to get the substance, use the substance or recover from its effects A great deal of time spent in activities necessary to obtain the substance, use the substance or recover from its effects  
Frequent intoxication or withdrawal symptoms when expected to fulfil major role obligations or when substance use is physically hazardous    
Important social, occupational or recreational activities given up or reduced because of substance use Important social, occupational or recreational activities given up or reduced because of substance use A higher priority given to drug use than to other activities and obligations
Continued substance use despite knowledge of having a persistent or recurrent social, psychological or physical problem that is caused or exacerbated by the use of the substance Continued substance use despite knowledge of having a persistent or recurrent social, psychological or physical problem that is caused or exacerbated by the use of the substance Persisting in use despite harmful consequences
Tolerance: need for markedly increased amounts of the substance to achieve intoxication or desired effect or markedly diminished effect with continued use of the same amount Tolerance: need for markedly increased amounts of the substance to achieve intoxication or desired effect or markedly diminished effect with continued use of the same amount Increased tolerance
Characteristic withdrawal symptoms Withdrawal: the characteristic withdrawal syndrome or the same (or a closely related) substance is taken to relieve or avoid withdrawal symptoms Sometimes, a physical withdrawal state

Substance often taken to relieve or avoid withdrawal symptoms

 

 

 

4.2 Does nicotine use through smoking meet standard diagnostic criteria for addiction?

This question is addressed by assessing nicotine intake through smoking in relation to the specific criteria listed in the DSM-IV or ICD-10 definitions, as follows:

A strong desire to take the drug. This characteristic is included in ICD-10 but not in DSM-IV. In addition, DSM-IV does not include craving or a similar item in its list of withdrawal symptoms. As discussed in Chapter 3, the desire to smoke plays a crucial role in relapse of smokers trying to give up smoking, is a manifestation of nicotine withdrawal and is clearly related to underlying dependence on nicotine.

Substance taken in larger amounts or longer than intended. This item is included in DSM-IV, and was originally designed to capture a feature of alcohol dependence.5 Although the DSM manual states that individuals who smoke are 'likely to find that they use up their supply of cigarettes … faster than originally intended',7 this criterion probably does not apply so clearly to nicotine and is not included in ICD-10.

Difficulty in controlling use. The concept of difficulty in controlling smoking is common to both DSM-IV and ICD-10 criteria. Much of the discussion of the psychological effects of nicotine in Chapter 3 relates to this criterion. It is also relevant that surveys of attitudes to smoking find consistently that the majority want to stop smoking (71% in Britain in 19978), and that a similar percentage believe that if they were to try to give up, they would fail.9 In the UK, about 80% of smokers have made at least one attempt to quit,9 and some 30% make at least one attempt each year.10 Only a tiny proportion of quit attempts succeed, so that only approximately 1% of smokers in the UK become long-term ex-smokers each year.11 Difficulty controlling use of smoking and nicotine is therefore self evident.

A great deal of time is spent in obtaining, using or recovering from effects of substance. This criterion is included in DSM-IV, but not ICD-10. Because cigarettes are legal and relatively inexpensive compared with other drugs of dependence, and because smoking can often be engaged in while doing other things, this criterion is less relevant to smoking.5 However, the more recent introduction of controls on smoking in the workplace in the UK and many other countries now mean that smoking at work is increasingly an activity which has to be pursued in a designated separate area, whilst the adoption of smoking restrictions in restaurants, bars, public houses and other public areas means that smokers are becoming less able to smoke when and where they choose outside the home. Therefore, as public perceptions and controls on the acceptability of smoking change, smokers are having to spend more time in activities specifically related to smoking; this criterion is gaining relevance as a result.

A higher priority given to drug use than to other activities and obligations. This criterion is included in both DSM-IV and ICD-10. In general, it is not applicable to smoking, because smoking has been a relatively socially acceptable activity in relation to the use of other drugs.5 However, there are circumstances in which priority is evidently given to smoking over other activities or obligations: for example, when an individual forgoes an activity because it occurs in smoking restricted areas, or when adults smoke at home and expose their children to the risks of passive smoke.

Continued use despite harmful consequences. This criterion is present in DSM-IV and ICD-10. It is clear from surveys that most smokers are aware of the health risks, and that this is one of the main reasons why they wish to stop.8,10 There is also substantial evidence that the majority of smokers continue to smoke after diagnosis of smoking related disease (see Section 5.2).

Tolerance. This criterion is also present in both DSM-IV and ICD-10. According to the DSM manual,7 tolerance to nicotine is manifested by absence of nausea, dizziness and other characteristic symptoms rather than by reduction in sought-after effects.

Withdrawal. As discussed in Chapter 3, one of the major motives for continued smoking appears to be the relief of the nicotine withdrawal syndrome.

Discussion

There is a question as to how far the current conceptualisation of dependence as it relates to cigarette smoking reflects one or more than one dimension. Johnson et al12 have reported data suggesting that the DSM-IIIR criteria reflect two factors, one relating to 'general dependence' and the other to 'failed cessation'. Given that the most important marker of dependence is probably the failure of attempts to stop, it may make more sense to consider the dimensions 'subjective' and 'behavioural' dependence, respectively. In relation to this model, behavioural dependence would appear to be the more significant from a public health and medical perspective.

It is also arguable that the social context and specific pharmacology of different substances dictate that different criteria be used as markers of dependence, and therefore that no single set of criteria can provide a universal framework for the definition of dependence or addiction. It is also evident from the above discussion that nicotine and smoking meet both the DSM-IV and ICD-10 criteria for substance dependence. 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 nicotine self-administration.

4.3 The history of social, cultural and political responses to nicotine addiction in Britain

Different substances have different addiction histories, and the terminology of addiction has also changed over time. The idea of some substances (opium, cocaine, alcohol) as addictive is well over a century old, while the idea of tobacco as an addictive substance is much more recent. This section aims to point to some reasons for this difference. It could be seen in terms of belated understanding or of attempts to hide the truth - but the 'scientific progress' or 'industry conspiracy' arguments mask a greater complexity. We argue here that the significance accorded to conceptual organising tools such as addiction reflects their different social, cultural and policy histories. The point at issue in this section is not whether addiction exists, but rather when, and why, does the concept of nicotine addiction assume significance in both social and policy terms? Here, there are clear differences between drugs or alcohol and smoking, which can be related to a complex of structural and institutional issues and their change over time.

Drugs, alcohol and addiction

For both opium and alcohol, theories of disease were not new even in the 19th century. Rush in the US and Trotter in Britain have been hailed as the 'discoverers' of disease in relation to alcohol addiction, with allied theories relating to opium following later in the century. The disease view of addiction was not 'progress', but rather part of a fundamental paradigm shift which characterised developments in insanity more generally.13 The language of disease in relation to alcohol was common earlier, in the 18th century. Those 18th century accounts were based on an associationist psychology of habituation, while those of the early 19th century drew on theories of moral insanity as paralysis of the will.14 What was new in the 19th century was not the theory, but the social and political significance accorded to it.

The temperance movement and teetotalism, with their emphasis on total abstinence, combined with the emergent medical profession to make disease theory the central interpretation of chronic drunkenness. This alliance developed rapidly in the last quarter of the 19th century and also drew on the allied, but distinct anti-opium movement. The primary focus of the latter was on the Indo-Chinese opium trade, but that agitation underlined a distinction between what were termed 'medical' and 'non-medical' uses of opium, the latter being aligned with addiction. In Britain, theories of hereditary degeneration and Lamarckian theories of the inheritance of acquired characteristics were drawn on in the concept of inebriety. This concept was applied to both alcohol and opium, and was organisationally supported by the work of the Society for the Study of Inebriety (founded in 1884).15 Degenerationist theories were of lessening significance before World War I. Belief in physical causation declined, to be replaced by the concept of 'addiction' to drugs as a 'disease of the will'. Here was the slippage between medical and moral concepts which marked much medical ideology of the time, especially in the sphere of mental illness.

This concept of addiction to drugs came to form the central plank of British drug policy from the 1920s, when the Rolleston Committee report of 1926 defined addiction as a disease requiring medical treatment, including maintenance prescribing. This was a 'harm reduction' approach, considered appropriate for the primarily middle-class drug addict clientele of the inter-war years, and reflecting 'mental medicine's' own shift of emphasis away from the asylum. After World War II, the specific role of psychiatry for both drugs and alcohol and for the treatment of addiction was established through a series of policy documents.15 Alcohol and drugs were both incorporated within the newer concept of 'dependence' which, with echoes of the 18th century theories, symbolised the enhanced importance of psychology and its interrelationships with psychiatry in the 1970s.16 For alcohol, these 'disease based' conceptualisations were in place alongside a public health population based approach which emphasised issues of individual responsibility and lifestyle, and was therefore in some senses opposed to the disease model. The concept of addiction to drugs remained more firmly entrenched in the 1980s and 1990s, although changing alliances brought psychiatric and public health/ preventive approaches into closer relationship, in particular through the enhanced focus on treatment as a mode of prevention.

Tobacco and nicotine

Tobacco and nicotine have had a different history. The scientific bodies dealing with inebriety did not so easily encompass the use of tobacco. In 1888, Norman Kerr, President of the Society for the Study of Inebriety, commented:17

Though no defender of tobacco, which it cannot be denied is a mere luxury, injurious to the health of many, even when used in moderation, I am driven to the conclusion that in the philosophical and practical meaning of the term, there is no true tobacco inebriety or mania.

Tobacco remained on the fringes of the late 19th century 'medical model'. Its significance was seen to lie rather within the public health model of the time. The issue of juvenile smoking evoked legislative control through the 1908 Children Act, but here the ideology was that of social hygienist concerns about national efficiency rather than of addiction or inebriety.18
Smoking therefore followed a different conceptual and policy route. The National Society of Non-Smokers, the leading anti-smoking organisation in the interwar years, focused not on 'disease' but on the clean air and environmentally harmful aspects of smoking. There was a strong moral emphasis on the selfishness of those who bothered others with their smoke.19 Medical input was limited, and medical writing on the subject was rare and tended to shy away from placing tobacco in the context of addiction.20 Unlike alcohol and drugs, tobacco was not poised for the post-World War II 'rediscovery of addiction', not having been conceptualised within the addiction model in the first place.

It was not disease/addiction but another scientific paradigm which came to predominate for smoking and tobacco consumption in the post-war years. This was the role of epidemiology and statistical inference, established in the British context by the work of Doll and Hill. Epidemiology gave smoking a different, albeit still medical, route into policy. Smoking and tobacco became a key issue in the new public health constituency forming itself around epidemiology in the 1950s and 1960s.21,22 Through the epidemiological route, smoking was set within a model of public health response, stressing taxation, health education and advertising controls - far removed from the disease/ dependence basis of psychiatric hegemony for drug and alcohol treatment being established at the same time.

As with opium and alcohol two centuries earlier, concepts of disease and dependence were not absent for smoking and nicotine, but they carried no primary significance, for reasons which will be discussed below. In 1942, Johnston's experiments with nicotine injections to counteract smoking had been carried out on the assumption that smoking tobacco was simply a means of administering nicotine, just as smoking opium was a means of administering morphine.23 The first Royal College of Physicians reports on smoking in 196224 and 197125 recognised that smokers might be addicted to nicotine. In line with theories current at that time, the discussion mingled the role of motivation with that of inheritance and personality. In Britain, research which traced the effects of nicotine more specifically was developed primarily in two locations. First, at the Institute of Psychiatry in the mid-1970s, where the technical development of the blood nicotine assay helped to establish the role of nicotine as the major controlling factor in smokers' regulation of smoke intake.26 Secondly, the tobacco industry was also establishing a sophisticated understanding of the role of nicotine in smoking behaviour. In the 1960s at the industry funded Tobacco Research Council's laboratories in Harrogate, researchers were investigating the role of nicotine in habituation through animal experiments, as part of the industry's focus post-1962 on developing safer smoking. This work was published in Nature,27 and other reports of the time show the clear industrial pharmacological interest in this aspect of smoking research.28
However, the developing concept of pharmacological addiction had little social and policy impact in the 1970s. The main 'treatment' model was smoking cessation, based on psychological models of behaviour modification and smoking as socially learned behaviour. Psychologists with an interest in decision making processes used research in anti-smoking clinics as part of this more general psychological emphasis. The primary 'treatment focused' concept in common use was psychologically-based dependence, rather than pharmacological addiction. The mainstream public health emphasis within anti-smoking activities was far removed from pharmacological research networks. The public health emphasis on education, on stopping smoking, on personal responsibility and free will was at odds with some of the implications of nicotine addiction. In the British context, there was no strong science/policy community around the concept of nicotine addiction in this decade. Public health and psychological perspectives predominated.29

The 1980s saw rapid change. Nicotine research expanded rapidly, in particular in the US after the earlier start in Britain in the 1960s and 1970s. Animal self-administration studies, together with many other types of study - neurochemical, absorption and dependence, craving and withdrawal, titration and effectiveness of nicotine replacement therapy (NRT) - all showed that nicotine was addictive. Behavioural studies in both Britain and the US finally confirmed that withdrawal symptoms were nicotine related.

NRT was found to reduce withdrawal symptoms.

These studies of nicotine were part of the huge expansion of psychopharmacology in this decade. Biomedical work was developed in alliance with epidemiological models and with biomarkers.30,31 Nicotine research emerged in the US in policy terms in the Surgeon-General's report on nicotine addiction in 1988.32 Like passive smoking (the other new 'scientific fact') of the 1980s, the acceptance of nicotine addiction had major effects on policy discussion in the 1990s. In the more legalistic context of US smoking policy, the concept became important in liability law suits involving the tobacco industry, in moves to regulate nicotine as a drug by the Food and Drug Administration (FDA) (see Chapter 8).

In the British context, the policy response to addiction has been different, with a revived focus on harm reduction, which had earlier been of significance in the late 1970s, but with relatively little emphasis on the control of either supply or use of nicotine products. The role of nicotine as the agent of tobacco addiction raised significant policy issues. It was pointed out that people smoke mainly for nicotine, but die from the tar and other unwanted components in the smoke.33 The establishment of the concept of nicotine addiction has dual implications for policy and practice. On the one hand, it could be a reason to maintain people on the drug; on the other, it could be a reason to wean them off the habit.31 There is a greater emphasis on the role of treatment and NRT, and a shift of position in the public health coalition to accommodate harm reduction.34

The contrast between the British and American responses to nicotine addiction recalls the different policy positions on illicit drugs in the 1920s, Britain adopting a medical maintenance model while the US favoured prohibition.

In general, these debates and the associated rise of the concept of addiction can be seen as part of the repositioning of both tobacco and nicotine, and of illicit drug use in the late 20th century. They epitomise the biomedical reorientation of late 20th century public health.29 However, it is evident that throughout this century nicotine products have tended to enjoy relatively favoured status compared with other addictive drugs, and that this status is starkly inconsistent with the harm that tobacco products cause.

4.4 How does nicotine addiction compare with addiction to other drugs?

In determining the appropriate medical, social and policy responses to nicotine addiction in Britain, it is appropriate to try to position nicotine in relation to other addictive drugs in terms of the degree of that addiction or dependence. In addressing this issue, however, it is important also to acknowledge the importance of drug delivery methods in determining dependence. This point was summarised in testimony by Dr Louis Harris before the US FDA on 3rd August 1994, on behalf of the College on Problems of Drug Dependence and the American Society of Pharmacology and Experimental Therapeutics. He stated that the development of dependence or addiction to drugs such as nicotine may depend on the method by which the drug is delivered, as well as the inherent characteristics of the drug itself, and testified as follows:

First, the great preponderance of data from both animals and man indicate that nicotine meets the criteria to be classified as an abusable and dependence producing substance. Thus, nicotine produces tolerance and dependence such that abstinence after appropriate dosing may result in withdrawal symptoms. In addition, the compound produces alterations of mood in humans and serves as a reinforcer and is self-administered by both animals and man. That's a given. Second, the psychoactive effects of nicotine are dependent on both dose and rate of administration and route of administration as well as rate. The inhalation route can provide high doses at a rapid rate that produce and sustain dependence.

Similar conclusions were drawn by the US Surgeon-General in 198832 and by the FDA.35,36 The fact that several characteristics of addictive drugs might be scientifically evaluated, and also that the effects of the drug depend in part on how it is delivered, complicate simple statements that equate all forms of nicotine delivery. These considerations also complicate comparisons of addictiveness of nicotine and other drugs because the answer might depend upon the measure and dosage form under consideration. None the less, it is important to try to evaluate the extent to which addiction to nicotine compares with addiction to other drugs. Is nicotine among the most addictive drugs of all, or is it no more addictive than coffee, tea, 'twinkies' (an American confectionery), jogging or carrots - as claimed by the tobacco industry in its statements before the US Congress (see Refs 36 and 37)? The answer to this question is complicated by consideration of the specific criteria considered and the dosage form evaluated.

Nicotine dosage delivery forms

First, let us consider the dosage form issue. Tobacco-delivered nicotine maximises the addictive effects of nicotine in several ways:

  1. Tobacco products, in general, and cigarettes in particular, provide remarkably palatable dosing systems. These mask the noxious effects of nicotine, which include burning sensations in the mouth, oral, nasal and pharyngeal regions, and which can occur at very low dosages when nicotine is given in pure form.
  2. Tobacco products provide a means of rapid, responsive and flexible dosage control which is important because the range of doses at which effects are positively reinforcing is narrow.
    Armitage et al38 described this as 'finger tip' dosage control with regard to the cigarette. Speed of delivery of nicotine from cigarettes is remarkable, providing nicotine 'hits' to the brain within seconds of smoke delivery to the lung.
  3. The engineering of cigarettes and many smokeless tobacco products employs pharmaceutical techniques to control nicotine dosage so that it will be optimal for the target population. In the case of moist snuff products, for example, products marketed to young people (termed 'starter products' by the company) use small amounts of buffering to produce low pH, slow-release nicotine systems. In contrast, products marketed to established snuff users are highly buffered to provide much higher and more rapidly delivered nicotine doses according to a scheme termed the 'graduation' process by one tobacco company.35,36 Cigarettes are remarkably fine-tuned dosing systems, with dosage consistently meeting standards set by regulatory agencies such as the FDA for approved drugs. Furthermore, their physical engineering means that cigarettes marketed most heavily can readily deliver approximately 1-3 mg of nicotine, as desired by smokers, regardless of their advertised or labelled delivery values.39
  4. The extreme lengths to which tobacco manufacturers went to employ physical and chemical engineering in cigarette design to maximise the addictive effects of nicotine have only recently been appreciated through the discovery by the FDA of documents and collections of expert accounts from former tobacco industry employees.35,36 The discovery process continues almost daily with reviews of tobacco industry documents now available because of litigation in the US. Taken together, this extraordinary engineering optimises the pH, the ratio of free base to bound nicotine in the smoke, the size of the inspired particles, the sensory effects of the inspired particles, and many other features of modern cigarettes. Cigarette smoke also contains chemicals which can act synergistically to produce effects that might be even more reinforcing than those of nicotine alone. For example, levels of acetaldehyde (a chemical involved in alcohol dependence) in smoke can be manipulated so as to produce a mixture that studies by Philip Morris35,36 indicated would be more reinforcing than either acetaldehyde or nicotine alone.
  5. Finally, other substances in cigarette smoke may produce effects that contribute to the addictive effects of cigarettes. Although research in this area is in its infancy, it is plausible that effects such as the potentially antidepressant monoamine oxidase inhibiting effects of smoke are due to non-nicotine compounds in tobacco and/or tobacco smoke.40

Whether the intent of this engineering is to maximise or minimise abuse potential, many aspects of the product itself, and how it is regulated and marketed operate to determine overall patterns of use (see Table 4.2).41 In contrast to tobacco products, approved nicotine-delivering drug products for treating tobacco dependence and withdrawal provide pure forms of nicotine in which dosage is controlled to minimise adverse (including addictive) effects. For example, nicotine patches deliver their nicotine so slowly as to preclude psychoactive effects. Delivery of nicotine from gum is potentially faster but heavily dependent upon determined activity by the user and still cannot mimic the cigarette. The sensory palatability of the pharmaceuticals is also finely balanced so as not unduly to reduce compliance with clinical guidance but also not to be overly attractive in their own right.

Table 4.2. Comparison of product design, labelling, and marketing strategies
and controls for tobacco products and nicotine treatment preparations (from Ref 41).

 

Tobacco products

Treatment products

Product design

 

Maximise pleasurable/reinforcing effects of addiction

Minimise all addictive effects

Maximise sensory appeal

Target acceptability to indicated consumer

Maximise packaging appeal

Target appeal to indicated consumers

Health risks 'accepted' and conferred to consumers

Health risks minimised 'Safety standards' set by regulation

Labelling

Covered by EU directive
Not subject to MCA approval
Health warnings required to cover 4-6% of pack surface

MCA approval required before marketing
Specific indications, cautions, warnings and messages required

Requirement to display machine-measured tar and nicotine yields
Human dose exposure data not required

Accurate data on nicotine dose content and delivery required

Exposure reduction claims (eg 'light', 'lower', 'reduced') unregulated

All claims relating to health improvement subject to MCA approval

Marketing

Initiate use in non-tobacco users

Use only for tobacco users

Create nicotine dependence

Treat nicotine dependence

Sustain use as long as possible

Use no longer than labelling or medical need recommends

Explicit youth targeting of some products

Minimise youth appeal

EU = European Union; MCA = Medicines Control Agency.

Consequently, the users of nicotine products such as oral gum, inhalers and nasal spray obtain little pleasure from use of these products, and in fact experience sensory stimuli which tend to discourage unnecessary use. These differences are best illustrated by the fact that, whereas most smokers use cigarettes much more and for much longer than they desire, most users of the nicotine replacement medicines use doses at levels below those advised by health professionals, and the incidence of abuse of these products is remarkably low.

Nicotine dosage delivery by cigarette

Keeping in mind the tremendous variation in the addictive effects of nicotine across delivery systems, let us now focus on the form which is the most troublesome from a health perspective, namely, the cigarette. Sufficient epidemiological and clinical evidence enables a systematic comparison of cigarettes and other addictive drugs according to various criteria. One such comparison was provided in a table in the 1988 Surgeon-General's report.32

More recently, Henningfield et al42 compiled a similar comparison (see Table 4.3). In brief, as shown in the table, the severity of the addictive effects varies across different measures. Although others may rate these features somewhat differently,43 the point remains that several different features of drugs might be considered and that no addictive drug exceeds all others on all points.

As illustrated in Table 4.3, and as has been concluded elsewhere,32,44,45 among the prototypic addictive drugs, nicotine delivered by way of tobacco products is a highly addictive drug. None the less, differences in specific features of addictive drugs and differences in the consequences of use have implications for regulatory approaches appropriate to each drug as well as to clinical approaches to treating individuals determined by the particular drug under consideration.45 Prominent features of particular distinction across addictive drugs are summarised below.

Table 4.3. Ranking of nicotine in relation to other drugs in terms of addiction factors of concern (from Ref 42).

Dependence among users

nicotine>heroin>cocaine>alcohol>caffeine

Difficulty achieving abstinence

(alcohol=cocaine=heroin=nicotine)>caffeine

Tolerance

(alcohol=heroin=nicotine)>cocaine>caffeine

Physical withdrawal severity

alcohol>heroin>nicotine>cocaine>caffeine

Societal impact

serious effects due to secondary deaths (nicotine), accidents (alcohol) or crime (heroin, cocaine); no substantial impact for caffeine

Deaths

nicotine>alcohol>(cocaine=heroin)>caffeine

Importance in user's daily life

(alcohol=cocaine=heroin=nicotine)>caffeine

Intoxication

alcohol>(cocaine=heroin)>caffeine>nicotine

Animal self-administration

cocaine>heroin>(alcohol=nicotine)>caffeine

Liking by non-drug abusers

cocaine>(alcohol=caffeine=heroin=nicotine)

Prevalence

caffeine>nicotine>alcohol>(cocaine=heroin)

Incidence, prevalence and risk of progression

Addiction to nicotine is far more common than addiction to cocaine, heroin or alcohol, and the rate of graduation from occasional use to addictive levels of intake is highest for nicotine in the form of cigarettes. Depending upon the definition used for occasional use, 33-90% of occasional users escalate to become daily smokers46 (see also Chapter 5). In contrast, even when highly addictive dosage forms of cocaine (ie smokeable 'crack' cocaine) are readily available in the US, the risk of progression from any use to regular use is the exception, not the rule. The 1988 US National Household Survey indicated that cocaine is currently used at least once per week by about 11% of people who have used cocaine in the past year and by about 29% of people who have used it in the past 30 days. For alcohol, approximately 10-15% of consumers of alcoholic beverages are problem drinkers. Although the absolute estimates may vary, an epidemiological study by Anthony et al47 on the risk of dependence according to the DSM criteria confirms these comparisons and conclusions.

Remission and relapse

Rates and patterns of relapse are similar for nicotine, heroin and alcohol,48,49 and probably for cocaine.50 An analysis of relapse to tobacco use showed that, in the context of a minimal treatment intervention approach, approximately 25% of persons relapsed within two days of their last cigarette and approximately 50% within one week.51,52 For people quitting on their own, the study by Hughes et al52 discovered that two-thirds were smoking within three days of their scheduled quit date.

Reports of addictiveness by drug abusers

Two studies specifically asked polydrug abusers to compare their addictions. The first asked drug abusers to rate their liking on an increasing scale from 1-4.53 Tobacco, cocaine, heroin and alcohol liking scales were 4.3, 4.2, 4.7 and 2.9, respectively. On the need scale, tobacco was rated most highly (3.3) and alcohol most weakly (1.3), while heroin was rated at 2.8 and cocaine at 1.5. A second study54 found that tobacco, when compared to other substances, was associated with equal or greater levels of difficulty in quitting and urge to use, but that its use was not as pleasurable. Using a laboratory-based approach, Henningfield et al55 found that cigarette smokers who also had histories of other drug abuse rated intravenous (IV) nicotine as similar to cocaine on key measures of addiction potential. These findings were recently extended by Jones et al56 in a direct, double-blind comparison of nicotine with cocaine given IV to human volunteers. This study also found similar effects of the two drugs on key measures of addiction potential. Of particular note was the finding that subjects frequently misidentified nicotine as cocaine, and at high doses, as an opiate.

Psychoactivity and euphoria

Among the first steps in determining whether a chemical has the potential to produce addiction is to determine if it is psychoactive.32 Psychoactive effects are often referred to in human studies as subjective, psychological, interoceptive or psychic, or in both animal and human studies as discriminative. As described earlier, nicotine and other comparison drugs all produce qualitatively distinct psychoactive effects. Of course, not all psychoactive drugs are addictive. Drugs such as chlorpromazine or atropine are psychoactive but not widely abused, and the psychoactive effects produced by these drugs are not generally considered highly pleasant in their own right.

One correlate of addiction liability is that a drug produces pleasurable or euphoriant effects in standard tests of drug liking and morphine-benzedrine group (MBG) scale scores.57-59 In polydrug users, scores on liking scales do not necessarily show quantitative differences between nicotine, cocaine, heroin, or alcohol.32 Scores on the MBG scale, however, are elevated by most addictive drugs, and these absolute values do vary across drugs.59 Such variation probably reflects qualitative differences in the effects of the drugs and not quantitative differences in addictiveness.

Reinforcing effects

The capacity of a drug to control behaviour leading to its repeated self-administration can be tested by giving animals or humans the opportunity to take it under standardised conditions. Nicotine, cocaine, heroin and alcohol serve as reinforcers for a variety of species.32,60 Cocaine appeared to be the more powerful reinforcer in several studies in which nicotine has been directly compared with cocaine.61-64 Analogous comparisons with opioids and alcohol have not been made, nor have other routes of drug administration been compared, thus weakening the strength of conclusions regarding possible differences in the maximal reinforcing potential of these drugs. None the less, cocaine appears to be the most readily established reinforcer for animals, generally requiring only simple access to the drug via an IV catheter.65,66 Therefore, whereas such studies confirm that the drug nicotine in tobacco products, the drug morphine in opium products, and the drug cocaine in coca-based products, respectively, define the drug dependency syndromes, such studies do not provide a basis for predicting how the reinforcing effects of the drugs will compare in products used outside the laboratory.

Physical dependence

Many drugs that are not abused also produce physical dependence, (eg anticholinergics, dopaminergic antagonists and calcium channel blockers).67 Among the addicting drugs, the most severe withdrawal syndromes are those which occur following extended administration of alcohol or short-acting barbiturates.68 Heroin and nicotine also produce clearly defined syndromes of physical dependence and withdrawal,32 and a syndrome of withdrawal from chronic cocaine administration has also been recently characterised.69 The symptoms of withdrawal from cigarettes appear to exceed those for all other forms of nicotine delivery; they are less severe than those produced by alcohol or heroin, but more severe than those from cocaine.32,70

Tolerance

The degree and type of tolerance that occur vary considerably across drugs. For example, nicotine, cocaine, heroin and alcohol can produce intoxication and disorientation,67 but tolerance to the intoxicating effects of nicotine and heroin is sufficiently pronounced for intoxication to be relatively uncommon in users with stable supplies of drugs.32,68 Conversely, the degree of behavioural tolerance to alcohol is so limited that automobile accidents are common in heavy drinkers. Nicotine tolerance has been widely studied since the turn of the 20th century.71 The degree of tolerance produced by nicotine is so pronounced that it can enable tobacco users to self-administer the large quantities of tobacco each day that lead to the high risk of disease and premature death associated with cigarette smoking.

Conclusions

On current evidence, we can conclude that cigarettes are properly categorised among the most addicting substances as this form of nicotine delivery maximises the addictive effects of the drug. The fact that nicotine is of low abuse potential in controlled dosage forms such as the transdermal nicotine patch or nicotine gum supports the conclusion that the form of delivery is an important determinant of its addiction potential. Thus, tobacco-delivered nicotine is of great concern, with the cigarette of greatest concern of all tobacco products because of its high toxicity and addictiveness.

The pharmacological effects of nicotine are not identical to those of heroin, alcohol or cocaine - nor, for that matter, are the effects of cocaine identical to those produced by heroin. In its arguments that nicotine is not addictive, the tobacco industry has often argued, as it did to the US FDA,36 that nicotine is not addicting because it does not meet criteria that the tobacco industry itself has developed. In essence, these criteria appear to be those achievable only by a drug whose composite profile would be as intoxicating as ethanol, would produce as severe withdrawal symptoms as ethanol or heroin, would have the euphoriant effects of cocaine, and would serve as a reinforcer for animals and naïve humans as readily as does cocaine.
Any one factor may be selected to argue that one of these drugs is more or less addicting than the others. However, this exercise makes it clear that addiction severity and society's level of concern about drug use are best evaluated by assessing several variables. We can, however, conclude, as was concluded in the 1988 Report of the US Surgeon-General,32 that:

The pharmacologic and behavioral processes that determine tobacco addiction are similar to those that determine addiction to drugs such as heroin and cocaine.

We can further conclude that tobacco dependence is a serious form of drug addiction which, on the whole, is second to no other.

4.5 Relevance to society of recognition of nicotine as an addictive drug

As described in Section 4.3, dependence on smoking and nicotine addiction has historically been afforded a relatively lower degree of significance than other forms of drug addiction in Britain. Indeed, it is still widely claimed that tobacco use is a pleasurable activity in which adults participate knowing and accepting the risks and, according to the Tobacco Manufacturers' Association:

Smoking is an adult pursuit and should remain a matter for informed and adult choice.72

Further, the principle of consumer sovereignty is well established in modern economic theory, and holds that consumers are the best judges of how to spend their own money. However, if smoking and nicotine are addictive, the argument that the individual adult consumer has a right to choose to purchase and use tobacco products, and that the tobacco industry has a right to continue to supply them, is difficult to sustain for the following reasons:

  1. Addiction to tobacco products creates a demand for habitual use which is no longer an expression of consumer choice. This point was acknowledged in confidential legal advice to the US Tobacco Institute in 1980, that:
    we can't defend continued smoking as 'free choice' if the person was 'addicted'.73
    The addictiveness of tobacco products compromises the free choice and consumer sovereignty of the smoker. Although it is possible to stop smoking, many find smoking cessation a difficult and unexpected consequence of smoking, and for some it represents an insurmountable obstacle. Deciding to smoke or make a purchase of cigarettes has an element of future commitment to smoking that may not be apparent to the smoker at the time of purchase.
  2. The vast majority (over 80%) of UK smokers start as teenagers or children.74 Young people do not always have the capacity to make informed decisions, and society generally recognises this by providing greater protections for children than for adults. For example, there are a large number of age-restricted products on the market including tobacco, and special children's rights are enshrined in a UN convention with articles establishing the child's right to good health.75 In the case of tobacco, the problem of immature decision making is compounded by nicotine addiction. Decisions to smoke made in the early teens can be consolidated into addictive behaviour before the smoker reaches maturity. A confidential Philip Morris marketing document explains this as follows: a cigarette for the beginner is a symbolic act. I am no longer my mother's child, I'm tough, I am an adventurer, I'm not square … As the force from the psychological symbolism subsides, the pharmacological effect takes over to sustain the habit.76
  3. Consumers can have poor awareness of the risks, and therefore make suboptimal decisions. This type of 'imperfection' is common in many product markets, but the consequences of ill-informed decisions about tobacco products may lead to serious harm or premature death. Though smokers generally know they face increased risks and are warned to that effect, they judge the magnitude and diversity of these risks to be lower and less well established than they actually are.77 As well as poor knowledge of the health risks such as cancer and heart disease, there is also poor knowledge of the risk of addiction, compounded by the difficulty in conceptualising addictive behaviour before experiencing it. A majority of school-age regular smokers believe they are no less or no more likely than others to be 'hooked on cigarettes when 20'.78 In the US, a study showed that teenagers overestimate the likelihood that they will quit smoking in five years' time.79 This knowledge deficit is not merely consumer behaviour that falls short of a theoretical ideal, but is at least in part the outcome of sustained public relations campaigns by the tobacco industry. For example, British American Tobacco advertised in The Observer, a British Sunday newspaper, in March 1998 stating: Whereas earlier definitions [of addiction] were based on objective criteria, the current definition is more colloquial, reflected in terms like 'chocaholic' and 'Addicted to Love' as in a recent movie. This colloquial definition is all inclusive and certainly applies to the use of many common substances that have similar mild pharmacological effects to cigarettes, such as coffee, tea, chocolate and cola drinks.80

The fact is, however, that in relation to the more objective criteria, smoking and nicotine use are addictive. They differ significantly from the colloquially defined addictions listed above in both the severity and strength of that addiction, and in the adverse health effects caused by the addiction. For practical purposes, and in major contrast to cigarettes, chocolate, coffee, tea, cola drinks and love do not kill.

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Contents

Contributors, Foreword and Key Points
1  Tobacco smoking in Britain: an overview
2 Physical and pharmacological effects of nicotine
3 Psychological effects of nicotine and smoking in man
4 Is nicotine a drug of addiction?
5 The natural history of smoking: the smoker's career
6 Regulation of nicotine intake for smokers, and implications for health
7 The management of nicotine addiction
8 Regulatory approaches to tobacco products in Britain
9 Summary and recommendations

 

 

 

 


This page last updated on May 8, 2001