Pharmacological and Psychological Aspects of Drugs Abuse
David J. Nutt
Fergus D. Law
Drug abuse, misuse, and addiction are major issues in society because of their enormous personal, social, and economic costs and their important psychiatric components.(1) Many drug treatment programmes are run by psychiatrists, and the evidence strongly supports the notion that a significant proportion of severe drug abusers are psychiatrically ill. Moreover, drug misuse appears to be becoming more frequent in patients with other psychiatric disorders, where it can lead to problems in treatment and poorer outcomes. It is therefore essential for all psychiatrists and related health professionals to have a good understanding of the basis of drug misuse.
Why do people take drugs?
A very common misconception is that drug misuse is simply a search for fun. In fact, people take drugs for many reasons other than to get the buzz or high. Indeed, studies have shown that straightforward pleasure seeking is the primary reason for initiation of drug use in fewer than 20 per cent of individuals. Whilst the high or buzz is the most obvious pleasurable effect, many people also describe using drugs to feel comfortably numb, pleasantly drowsy, or full of energy and confidence. Many others will be chasing the high or buzz that they first experienced, always seeking the intensity of their first experience. Still others will be selfmedicating for anxiety, anger, pain, boredom, lack of motivation,
lack of self-confidence, and many other aversive states including drug withdrawal.
lack of self-confidence, and many other aversive states including drug withdrawal.
The main reason to try to ascertain the reasons for drug use is that in many cases identification of the cause can lead to effective interventions. For example, many alcoholics will point to anxiety as their reason for drinking;(2) indeed, social anxiety is one of the most common causes of alcoholism in young men.(3) If this can be treated (e.g. by selective serotonin reuptake inhibitors) then they are frequently able to become abstinent or even drink normally. Social anxiety and attention-deficit disorder are common reasons for the use of stimulants. Depression, is particularly likely to lead to excess alcohol intake, and a vicious cycle can develop because both alcohol and its withdrawal are depressogenic. Alcohol is also one of the most serious risk factors for suicide. There is increasing use of stimulants and cannabis by schizophrenic patients. In part this reflects the behaviour of their peer group but in part is because they can offset some of the more negative aspects of the illness and medication side effects. As both these types of drugs can worsen psychotic illness, dealing with drug misuse in this group is a priority.
Other factors affecting drug use may be less amenable to psychiatric intervention, such as pressure from peers or others. For instance, female opiate addicts often have a male partner who also uses drugs or even deals drugs. Should she stop use, relapse is almost certain to occur if she continues to live with this partner. Another reason for drug use is to reduce pain or boredom, the latter being a common reason given by disadvantaged youth in areas of high unemployment and poor environmental quality such as inner cities or out-oftown housing estates. Other reasons for drug use, especially with the psychedelics, include the search for meaning or for mystical experiences. Whilst not directly relevant to psychiatry, this use can precipitate psychotic episodes in susceptible individuals and may trigger schizophrenia.
Finally, it is important to remember that the reasons for use of a specific drug are not static. An opiate addict may use the same dose of heroin to get going in the morning, to ‘top off’ a pleasant experience later in the day, to deal with angry feelings when they occur, and to promote sleep at night. Similarly during a drug-using career different motivations may become dominant. This has been well characterized in opiate users where for many the initial use was for pleasure or escape. Over months, as physical dependence becomes increasingly apparent, use becomes driven by the need to avoid withdrawal and to feel normal at almost any cost.
Drug use and misuse
It is possible to view the issue of drug abuse from different perspectives, which range from the molecular and genetic through the pharmacological to the psychological and social. Each view has its merits and is important, but there is little doubt that an integrated view is necessary, because for most drugs and for most societies no one perspective can explain all the known features of drug abuse. However, for the purpose of this chapter we have concentrated on the psychological and pharmacological.(1,4, 5 and 6)
Problem use, addiction, dependence, and craving
These are some of the most commonly used terms regarding drug misuse but at the same time they are also the most problematic. The use of drugs in any circumstance, therapeutic, or otherwise, can be associated with problems, although the nature and scale of this varies (see Table 4.2.1.1). The terms problem use and misuse usually refer to use of drugs (prescription or otherwise) for pleasure but with disregard for the personal or social dangers. For example, alcohol misuse can lead to irresponsible behaviour whilst intoxicated and, if prolonged, to liver, gastric, and nervous system damage without the individual necessarily being addicted or dependent.
Table 4.2.1.1 Potential problems with drug use | ||||||||||||||||||||||||||||||||||||
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Addiction is a term that had become so misused in general parlance and had acquired such a pejorative edge, that in the past two decades attempts have been made to remove it from the psychiatric lexicon. Unfortunately, the replacement terminology of dependence, or the dependence syndrome, has been similarly devalued by popular usage. In fact there exists a spectrum of dependence ranging from physiological supplementation (as with insulin in diabetes mellitus) through to life-altering dependence on illicit drugs such as heroin (see Table 4.2.1.1). Addiction is still a useful construct if it is reserved for the collection of phenomena that occur at the extreme end of the dependence spectrum, and includes the concept of social and personal decline associated with drug use, as well as craving, tolerance, and withdrawal symptoms (cf. DSM-IV and ICD-10).
Another area of some confusion is the distinction between physical and psychological dependence. When originally conceived, this distinction was helpful in that it emphasized that drug dependence was more than just physical adaptation to drugs as manifest by withdrawal symptoms, and that psychological processes, especially drug liking, were also important. However, drugs without obvious physical withdrawal syndromes (e.g. stimulants) also result in measurable physiological withdrawal changes in sleep and activity as well as measurable psychological changes such as those in mood. In addition, new neuroimaging techniques such as PET, SPECT, and functional MRI are beginning to reveal the brain circuits underlying the pleasurable effects of drugs, and this has
resulted in a blurring of the distinction between physical and psychological processes. For example, the plate shows a PET scan of heroin addicts in which the brain regions showing increased blood flow activated by craving for heroin are illuminated using the radiotracer oxygen-15 (Plate 4.2.1.1). Similar studies have revealed the brain regions involved in the pleasurable effects of opiates and stimulants.(7) Thus there is a clear convergence in terms of mechanisms, but in terms of treatment regimens the distinction between physical and psychological remains.
resulted in a blurring of the distinction between physical and psychological processes. For example, the plate shows a PET scan of heroin addicts in which the brain regions showing increased blood flow activated by craving for heroin are illuminated using the radiotracer oxygen-15 (Plate 4.2.1.1). Similar studies have revealed the brain regions involved in the pleasurable effects of opiates and stimulants.(7) Thus there is a clear convergence in terms of mechanisms, but in terms of treatment regimens the distinction between physical and psychological remains.
Craving is also a term that is widely used yet ill-defined. Craving is a desire, which most commonly is taken to mean a strong and sometimes irresistible desire to use a drug. The emotional valence of craving is not necessarily pleasurable. Craving can reliably be elicited in situations of negative valence. It is commonly found in withdrawal, when it can lead to relapse. Craving can also be present as an urge or desire to use a drug although the sufferer may be actively denying or resisting its presence. The complex interplay of physical and psychological processes is well exemplified by the physical responses that craving can produce. For example when opiate-dependent subjects are shown drug-related paraphernalia they may experience emotions that range from pleasurable anticipation to early withdrawal (shaking, tearing of the eyes, pupil dilatation, etc.). Each one of these experiences can lead to a desire to use the drug, that is craving.
Studies in both animals and humans have demonstrated that conditioning occurs to both the positive and negative aspects of craving.(8) Tolerance is to a large extent a conditioned response, particularly related to the environmental context in which a drug has been taken.(9) Thus an environmental context which is drug familiar results in physiological changes in the brain in preparation for the drug effect, and thus less actual drug effect occurs (i.e. tolerance). However, in a novel context, such preparatory changes do not occur so that a standard drug dose will result in a larger drug effect and a potentially fatal outcome. Thus the lethality of a drug is largely dependent on the environment in which it is taken.
Attempts have been made to dissect out the subcomponents of craving using questionnaires. The best known of these are the set designed by Tiffany et al.(10) who independently rate the five main subcomponents of craving—urges and desires to use, intention and planning to use, anticipation of positive outcome, anticipation of relief from withdrawal or negative outcome, and loss of control over use. Ongoing neuroimaging studies are beginning to support this multiprocess view of craving by revealing activation or inhibition of different brain regions to be correlated with individual symptom clusters.
There is also increasing evidence that the particular cognitions of patients may be important for treatment, especially during withdrawal. Just as panic disorder patients have catastrophic cognitions, addicted patients may have a high fear of craving and other withdrawal symptoms in association with related catastrophic cognitions. This detoxification fear has been measured in opiate addicts, and shown to predict outcome.(11) Withdrawal expectations also play a significant role,(12) and a 15 to 30 min explanation of what the opiate detoxification involves may reduce the measured withdrawal distress by over one-third. Indeed, such is the strength of psychological factors in addiction treatment, there is little doubt that drug treatments should always be combined with the appropriate psychological interventions.
Psychological processes and treatment implications
One of the most influential models in addiction treatment is known as the stages of change model.(13) The stage of change that a person can be identified as being at determines the therapeutic approach and type of treatment offered. Thus at the precontemplation stage where there is no recognition of a need for treatment, there is no point in offering intensive treatment interventions. Similarly, at the contemplation stage when treatment is being considered, the appropriate intervention is to help the person clarify their views and build their motivation to change rather than offering active treatment. Indeed, it is only in the decision and action stages that treatment should be actively offered and facilitated.
The brief counselling technique of motivational interviewing(14, 15 and 16) has been proved to improve outcome effectively, and ties in well with the stages of change model. In the early stages the therapy is focused on encouraging the patient to reduce or resolve their ambivalence, which acts as their psychological barrier to treatment. The patient in this client-centred but focused therapy is facilitated to discover the solutions to their own problems themselves. This approach of accepting the client’s current level of thinking (rather than offering ready-made solutions, or confronting them, or trying to argue them into the solution) has been shown to be surprisingly effective in the clinical trials.(16) The effectiveness of this technique has resulted in a new understanding of motivation, which is seen as a dynamic state rather than as a fixed state, and one which can be influenced by the therapeutic stance.
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