Throughout history, and in all parts of the world, people have wanted to alter the ways they feel, perceive and behave. For some the reason has been religious; for others it is a search for knowledge; for many the reason is simply to obtain pleasure. Meditation, extreme physical exercise, specialized techniques of breathing, starvation and self-punishment all are capable of altering a person’s mental state. But there has always been another, faster, easier route to altered mental states: the consumption of plants and plant extracts. The effects of these substances were once considered gifts from the gods, but we now know that plant substances (and some animal ones) exert their influence by chemical action. They are drugs. There is thus nothing new about drug use. What is new and different is the immense variety and widespread availability of drugs nowadays. Modern chemistry has added many man-made substances to those available naturally from plants and animals. And through improved processes of extraction and refining, scientists have greatly increased the power of those drugs still obtained from a natural source. The term ‘drug’ covers all chemicals that affect the functioning of brain and body. Most are used therapeutically, that is, only taken if there is a medical problem. But there are a few dozen natural and synthetic compounds that produce effects on the brain which are found rewarding in their own right. Such drugs are not used simply as a cure for disease and can therefore easily be over-used – hence the problem of drug abuse. Humans are not the only creatures that take drugs when there is no real medical need. Experiments show that many species of laboratory animals, when given a choice between pure drinking water and water containing alcohol, choose the alcohol. The same is found with several other drugs widely used for non-medical purposes.
Drugs in daily use
Of course the substances we dose ourselves with are not confined to the kinds of chemicals we obtain on prescription from the doctor. Many mindaltering drugs are in such widespread and daily use, and have such minor effects, that we have to remind ourselves that they are drugs at all. An obvious example is the caffeine in tea and coffee. The nicotine in tobacco, and alcohol, on the other hand, are potentially lethal drugs. The link between lung cancer and smoking has been established beyond reasonable doubt; and heavy alcohol consumption may lead not only to physical disorders, such as cirrhosis of the liver, but to severe psychological disturbance. Indeed, it could be argued that were alcohol and nicotine newly-discovered substances, their use would be rigorously controlled by legislation.
The ‘soft’ drugs, cannabis in particular, occupy an intermediate position. Whether they are accepted by people depends on age and the social group 130 concerned. In most countries cannabis use is illegal, but even then the crime is often regarded as minor. ‘Hard’ drugs such as morphine and heroin are a different matter. They are at the far end of the spectrum of legal and social disapproval.
Categories of drugs
There is no completely clear-cut way of grouping drugs. Many have a variety of effects, depending on factors such as the amount taken, the psychological state of the person taking them, and the way the drugs are administered. But there is a broad division between substances that have stimulant effects on the brain and those that depress its overall activity. Brain activity can be thought of as a dynamic spectrum, with extreme sedation (sleep) at one end and extreme activity at the other. Drowsiness, boredom, alert interest and over-excitement are stages in between. A stimulant drug such as amphetamine shifts a person towards the higharousal end of the spectrum; depressants like alcohol and barbiturates move the brain towards the lowarousal end. So someone who wants to stay up late at night, to work or enjoy a party, may take amphetamine, whereas someone who is too excited to sleep may use a sedative or depressant drug. People can also use drugs to adjust their level of arousal to when they feel happiest.
This makes drugs sound like useful tools. In some circumstances they are. But no drug, whether used under medical supervision or not, is totally problem-free. All have side-effects. And with a drug that is in some way pleasant to take, the temptation is to keep on taking it. The body then develops ways of counteract the drug’s effects, leading to the phenomena of tolerance and physical dependence.
The most important drugs of abuse are the opioid compounds, members of the sedative class of drugs. Taken in large enough quantities they induce a dulling of consciousness (and consequently relief of pain) merging into sleep; for this reason they are called ‘narcotics’. The original member of the opioid family is opium, obtained from the poppy Papaver somni-ferum which is grown widely from Turkey through to India and South-eastern Asia and China. To prepare the drug the unripe seed-head of the plant is cut, causing a milky substance (soon turning brown) to ooze out, which is collected and dried. For thousands of years opium has been eaten, smoked or drunk (dissolved in alcohol) as a tincture. Its sedative properties were known to the Ancient Egyptians. European interest in the drug arose in the seventeenth century, and by the nineteenth it was widely used – in Bohemian circles as a means of inducing euphoria, and by parents as a way of keeping babies quiet.
Dependence on opium occurred even when the drug was used medicinally for its pain-killing (analgesic) properties, as often happened during the American Civil war (1861-1865). But the problem grew with the isolation of morphine which, with codeine, is opium’s most important active ingredient. This was because morphine could be injected directly into a vein, and it seems to be a general feature of drug use that a compound which is injected has a faster, more powerful, and more addictive effect than when that compound is eaten or drunk. In the late nineteenth century, a new drug called heroin was made from morphine by a slight chemical alteration of its molecular structure. Morphine and heroin are extremely valuable in the control of pain, especially in people who are dying and who therefore do not fear addiction. But as heroin can be produced relatively easily in a makeshift laboratory it has become the most serious drug of abuse. Heroin can be sniffed, smoked, swallowed, or injected either into a vein (intravenously) or a muscle (intramuscularly). Intravenous injection produces an intensely pleasurable sensation, or ‘flash’, which has been compared to orgasm. Recently a new form of use, called ‘chasing the dragon’, has spread to Europe and the United States from Hong Kong. In this technique, heroin is heated on metal foil and its fumes inhaled. The body soon develops tolerance to the euphoric effects of the drug, and the doses taken must escalate to produce the same result. The digestive system, however, is unable to compensate for the presence of heroin, and regular users of this and other opioid drugs can suffer from chronic constipation. That is hardly the most serious problem, however. The drug’s depressant actions affect the parts of the brain controlling respiration, and coma and death may follow an overdose.
There are also serious medical risks in repeatedly injecting any drug. Veins become inflamed, clots form, and infection causes local sores which may spread to the whole body if the user does not scrupu-lously sterilize all materials and needles. Infection by the hepatitis virus, which damages the liver, and by bacteria that destroy the valves of the heart are also common problems, caused by using dirty needles. In the last few years, intravenous drug users have been shown to be among those members of the population identified as having a higher than average chance of contracting the virus responsible for AIDS (Acquired Immune Deficiency Syndrome), a disorder that damages the body’s ability to fight disease. So far, research suggests that the virus is passed on through direct contact with the blood, or other body fluids, of an AIDS sufferer. Drug addicts who share unsterilized hypodermic needles are thus at risk. Aside from medical problems, the heroin addicts face the need to find the large amounts of money required to support their habit. Many addicts turn to crime and prostitution; others become ‘pushers’, selling drugs supplied by someone else for a share in the profits, or – more commonly – merely for the price of a ‘fix’, a dose of heroin. Heroin has always been big business, but the person least likely to benefit financially is the ‘junky’, or addict, in the street. Once someone is addicted to heroin, the only hope is to ‘kick’ the habit. If a regular user stops taking heroin, major physical symptoms of withdrawal develop within four to 12 hours and last several days. These include anxiety, restlessness, pain, sneezing, insomnia, nausea, vomiting and diarrhoea. The symp-toms are the result of over-reactions of mechanisms that the addicted body has developed to counteract the depressant effects of the drug. The addict feels cold and the body hairs stand on end, giving the skin the appearance of gooseflesh. These effects probably lie behind the colloquial description of withdrawal as ‘cold turkey’. Similarly, the term ‘kicking’ the habit may relate to involuntary muscle movements that occur in the limbs.
As well as deriving drugs from the opium poppy, chemists have developed synthetic substances that have similar effects. These drugs are generally simpler versions of the original opioid molecules. Two of the most important are pethidine and methadone. Peth- idine is a valuable painkiller, but methadone’s most important role is in helping morphine and heroin users wean themselves away from addiction. Methadone does not produce euphoria, but relieves withdrawal symptoms. This means that opioid addicts can be switched to methadone and then the dose gradually reduced. The method has no guaranteed succes, however, and a few people stay dependent on methadone and have to be given oral ‘maintenance’ doses.
Barbiturates, like opioids, are major depressants. Before their addictive properties were recognized, they were prescribed extensively as sleeping pills and to reduce anxiety. They are now used much less frequently, although they still have an important medical role as a way of preventing epileptic convulsions. The risk of addiction is caused by the euphoria which is a side-effect of barbiturates. Barbiturates such as phenobarbitone can be taken as tablets or injected. Tolerance to the drug develops, although the escalation of dosage necessary to experience the same effect is not as dramatic as with the opioids. Withdrawal symptoms are severe: anxiety, restlessness, poor sleep, hallucinations, nausea and vomiting are all common and can even lead to death. But particularly dangerous are the convulsions which may follow sudden withdrawal of the drug. An additional complication of heavy barbiturate use is that babies born to women dependent on the drug will have become addicted in the womb and suffer the effects of withdrawal at birth. (This is true also of babies born to women addicted to opiates such as heroin.) Overdosing on barbiturates causes coma, poor or intermittent breathing and, in severe cases, even death. Indeed, these drugs used to be a favourite way of committing suicide. For this reason, and be-cause they quickly induce dependence, barbiturates are not now prescribed frequently by doctors.
Another factor in the decline of medical prescriptions for barbiturates was the development of a new class of drugs, the benzodiazepines. Examples are diazepam, lorazepam and nitrazepam. The ‘benzos’ are widely used to promote or aid sleep (chemicals having this effect are termed ‘hypnotics’) and to combat anxiety in much the same way as barbiturates. An overdose of benzodiazepines is not very dangerous, however, and because their effects are not perceived as particularly pleasurable, abuse is infrequent. Nevertheless, it has recently been shown that dependence can develop, and doctors now prefer not to prescribe benzos for more than a few weeks at a time.
Inhalants and other sedatives
A variety of sedative drugs, such as chloral hydrate, the bromides, and meprobamate, are occasionally misused, though they do not form a major part of the general drug problem.
The inhalants are a recent arrival on the drug scene. They are a wide range of chemicals found in such substances as glues, petrol, paint thinners, hair sprays, room deodorants and engine coolants. Because they are readily available, and there is no legal restriction on their sale, those drugs are most often abused by the very young, often children not yet in their teens. Their common characteristic is that they vapourize easily and can be inhaled. Sometimes the vapour is concentrated in a plastic bag before being ‘sniffed’. The effect is generally a sedative one, depressing the central nervous system. This produces an intoxication similar to the drunkenness caused by alcohol, but clears from the system much more quickly. ‘Sniffing’ chemicals is a very dangerous habit because it can result in irreparable brain damage.
Entirely distinct from the sedatives are the stimulant drugs, which increase the activity of the brain. Caffeine, present in coffee, tea and cola drinks is a mild, commonly used, stimulant and is not generally considered to be a problem. This is not so with the amphetamines. Known as ‘speed’, amphetamines produce feelings of alertness, energy and euphoria, and overactivity of thought, speech and action. Appetite is also reduced, and amphetamines were widely pre-scribed as slimming pills until doctors recognized their tendency to induce dependence. Prolonged use leads to delusions, hallucinations and characteristic movements, especially of the mouth. These symptoms are similar to schizophrenia, and are termed amphetamine psychosis. An overdose of amphetamines can lead to convulsions and death.
The euphoriant and stimulant effects of cocaine are similar to those produced by amphetamines, although the former has not been shown to produce physical withdrawal symptoms. Cocaine can be taken by injection (the fictional detective Sherlock Holmes used this method) or by ‘snorting’ the powder through the nose. This is now the most commonly used technique, and it is part of cocaine’s ‘jet-set’ image that this is done through a tube made from a rolled-up bank note of large denomination. Despite its current status as a drug used almost exclusively by the wealthy, cocaine is a drug of humble origins. It is extracted from the leaves of the tree. South American Indians still obtain the drug by chewing the leaves, and use it as a way of combating hunger and fatigue.
Although they exert their effects primarily on alertness and mood, both sedative and stimulant drugs are capable of producing disordered thoughts and unreal perceptions. But such effects are most clearly associated with another class of drugs, the hallucinogens. These compounds are also called psychedelics and occasionally psychotomimetics, because their effects resemble certain features of severe mental illness (psychosis).
The classic hallucinogen is LSD (lysergic acid diethyl-amide) often known simply as ‘acid’. This drug was first made in 1938 by two Swiss chemists, Arthur Stoll and Albert Hofmann, who were investigating com- pounds similar to those found in ergot, a fungus that sometimes grows on rye and wheat. The drug’s hallu-cinatory effects were discovered by Hofmann in 1943 when he accidently swallowed a small amount of the drug.
LSD is taken as a small tablet or on pieces of paper impregnated with the drug. The periods of intoxination, commonly called ‘trips’, last up to 12 hours and involve vivid sensations of colour, fantastic visions, and confusion of the senses (synaesthesia) in which, for example, the user ‘sees’ sounds. Many people claim that the drug produces mystical and artistic insight.
Thought and perception are so distorted that people who take LSD have unintentionally done themselves serious damage. Some users imagine they can fly and leap out of windows several floors up. There is also the risk of a ‘bad trip’ in which the hallucinations are terrifying rather than pleasant. Moreover, days or weeks after an LSD session flashbacks may occur in which the effects of the drugs are re-experienced. Despite these extreme effects on the brain, LSD has not been shown to produce physical dependence. Substances that have effects similar to LSD occur naturally in plants. The hallucinogen psilocybin is found in mushrooms – either the Central American variety, Psilocybe mexicana, or in Psilocybe semi-lanceata, or ‘magic mushroom’ which grows in Europe. The hallucinogen mescaline comes from a Central American cactus Lophophora williamsii, known locally as ‘peyote’.
Cannabis is a drug in a class of its own. Its effects -commonly known as being ‘stoned’ – are euphoria, relaxation, enhancement of sensations (which has given the drug popularity in artistic circles) and amusement. In high doses it is capable of acting as a hallucinogen and producing disordered perception. Cannabis is derived from the Indian hemp plant Cannabis sativa, which contains a family of drugs called the cannabinoids. The drug comes in various forms. The leaves and stalks are known colloquially as marihuana, ganja, pot, weed or grass. More powerful effects are obtained from hashish, a resin collected from the flowers of the plant. Cannabis is also prepared as a highly potent oil. All these forms can be either smoked or eaten.
The development of tolerance does not seem to be a problem with cannabis. In fact, there is some evidence of ‘reverse tolerance’, whereby the regular user requires less of the drug to get stoned than the novice. Although cannabis users may develop a strong drug habit, dependence is primarily psychological, and physical withdrawal effects are rare. Also, there is little evidence to suggest that cannabis necessarily leads to the use of ‘harder’ drugs, such as heroin, although this question is still being hotly debated.