Part 3: The health and social consequences of drug abuse drug-specific withdrawal symptoms and ‘craving’ – a slavish urge to find and consume more of the drug. This condition is both psychological and INTRODUCTION physiological, but has a biochemical explanation: the body’s ability to reproduce chemicals naturally The principal characteristics of the drugs covered becomes depleted by artificial chemical stimula- by this report are their potential for altering mood tion, causing a deficiency when the drug is no and behaviour and for creating dependence. Al- longer available. though many of them have considerable therapeu- tic value, they are also widely misused, thereby Tolerance occurs when repeated use of a drug creating a series of adverse consequences for requires the consumer to increase dosage in order society. The aim of this chapter is to examine the to experience the same “high”. Cross tolerance different kinds of drug which are abused and to exists within a specific drug type, for example the consider their impact on the individual and the synthetic opiate methadone shows cross tolerance community.* with morphine, while reverse tolerance implies an increased responsiveness as a result of past con- Nerve cells in the brain communicate with each sumption. The shortest time that must elapse other by means of naturally produced chemicals before repetition of the dose has a similar effect to known as neurotransmitters. A cell releases a neuro- the one before is called the critical interval. transmitter into the space between nerve endings is chemically processed or metabolized known as the synapse; the molecules are then much faster than heroin and therefore has a much picked up by receptor proteins on the surface of the shorter critical interval. second cell. In the normal course of its activities the brain releases and absorbs neurotransmitters such The health consequences of use as dopamine, norepinephrine and serotonin. Many depend on the interaction of two sets of variables, drugs, including those with addictive potential, namely the characteristics of the drug and those of work by imitating or releasing these neurotrans- the consumer. mitters or by blocking their actions. Blocking drugs, which occupy drug receptor sites in the brain and The former include bind to them, are known as antagonists, while imi- • pharmacological properties; tating drugs are known as agonists. The existence • route of administration, i.e. oral ingestion, snort- of different pathways in the brain means there are ing, inhalation, injection (subcutaneous, intra- many different types of neurotransmitter and many venous or intramuscular); different kinds of receptor, and the type of effect a • whether it is taken alone or together with other drug produces depends on the type of neurotrans- drugs or alcohol; mitter it reacts with. Cocaine, for example, blocks • level of purity and presence of adulterants; the brain’s ability to reabsorb dopamine, with the • dosage level. result that the neurotransmitters remain trapped in the synapse, stimulating the receptors over and The latter include over again. Prolonged stimulation causes the • personality of the user; reward, or pleasure associated with the drug. The • intensity or frequency of previous use; greater the reward, the greater is the inclination to • user’s pre-existing state of health; repeat the experience. • social and economic circumstances of the user; • the user’s expectations of the drug’s effects In laboratory studies the dependence potential of a (see Part 2). drug can be measured by how long and hard an animal will work to maintain supplies. In human The existence of so many variables means that beings, is characterized by the effects of drugs can differ widely from one

* The authors acknowledge a debt throughout this chapter to UNDCP, The Social Impact of Drug Abuse, a Position Paper for the World Summit for Social Development (UNDCP/TS.2, Vienna, 1996).

71 individual to another. Some people may suffer no illicit drug use is that the consumer – the last buyer serious side effects from a single experiment with in what may be a long chain of distribution – is drugs while for others it may be the beginning of a rarely able to verify the dosage or the purity of the purchase. The absence of quality control and the furtive conditions in which drugs are Drugs can alter mood and behaviour dealt and consumed may result in acute and create dependence. Consequences poisoning – heroin may be diluted with strychnine or supplied in an excessively pure of their use depend on characteristics dose leading to death; gullible youngsters of both drug and consumer. buying drugs at a ‘rave’ party can have no idea of what chemical cocktail is about to bombard their brains. lifetime . Even a single experience can provoke an acute toxic reaction, while chronic Drug types are described in various ways, depend- effects come from the body’s response to regular, ing on origin and effect. They can either be long-term abuse. Either pattern of use can lead to naturally occurring, semi-synthetic (chemical dependence and to an impairment of the body’s manipulations of substances extracted from natural organs or its functions, or both. Unsupervised drug materials) or synthetic (created entirely by labor- use may also have secondary effects in that it may atory manipulation). The principal categories are as conceal or delay recognition of genuine illnesses follows: requiring treatment. 1. Opiates: the generic name given to a group Estimates of morbidity and mortality are used to which includes naturally occurring drugs derived gauge the consequences of acute and chronic drug from the opium poppy (Papaver somniferum) such abuse. Morbidity indicators help us to under- as opium, morphine and codeine, semi-synthetic stand the association of drugs with illness and substances such as heroin (the foregoing are opi- disease by providing information on the numbers ates in the strictly correct definition); and opioids and frequency of treatment requests, drug-related – ‘opiate-like’, wholly synthetic products such as emergency room incidents at public hospitals, hos- methadone, pethidine and fentanyl. Opiates pitalizations and prevalence of communicable depress the central nervous system and are used diseases relating to drug use. Mortality data tell us therapeutically as analgesics (painkillers), as cough how many deaths are directly linked to the use of suppressants and against diarrhoea; in non-medical psychoactive drugs. Together these give us an est- usage as euphoriants and as a means of reducing imate of harmfulness. anxiety, boredom, physical or emotional pain. Heroin is often the opiate preferred by consumers The term overdose is often applied in the case of because it is relatively potent, easily dissolved in drug-related mortality but in many cases death (or water for injecting and penetrates the blood-brain barrier more quickly than morphine. Effects may last from 4 – 6 hours. Heroin can also A single experience can provoke an acute be snorted, smoked or inhaled by the toxic reaction, chronic effects come from method known as ‘chasing the dragon’ whereby it is heated on foil and the fumes long-term abuse. inhaled. The effects of methadone, which is usually taken orally, may last up to 24 hours. acute illness) may not be due to an excessive quan- tity of the drug but to an interaction with other It can happen that opiate dependence brings few psychoactive substances or with adulterants used physical complications other than constipation, but by retailers to bulk out the dosage units. These such cases are rare; studies of British heroin addicts impurities may do as much, if not more, harm than in the 1960s showed that even when maintained the drug itself. An important factor underlying all on medically prescribed ‘clean’ heroin and supplied

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