DEFINITIONS Drug misuse implies the use of drugs outside social, medical or legal norms. It is widespread among young people in the UK. Although statistically it is strongly linked with violent and criminal behaviour, there are large numbers of ìweekendî or ìrecreationalî drug users who do not come in conflict with the law and who would claim that their drug taking is no more abnormal than drinking alcohol.

Relevant terms include:

• Addiction: dependence on drugs with consequent detriment to social, physical or economic function.
• Dependence: psychological dependence is a strong desire to take a certain drug to produce pleasure or relieve distress, and physical dependence is indicated by the development of bodily symptoms if the drug is withdrawn.
• Tolerance: physical adaptation to a drug, leading to a need for increasing dosage to achieve the same effect. Tolerance often precedes development of physical dependence.

EPIDEMIOLOGY

Age: illegal drug-taking largely occurs in adolescents and young adults; up to 50% of teenagers experiment with illegal drugs but most have stopped using by their 20s. The most commonly used drug is cannabis. There was apparently an overall rise in prevalence, which has persisted, in the early 1990s, probably in association with the emergence of "dance" culture.

Although older people occasionally continue with illegal drugs, even up to their 50s or 60s, a much greater problem in middle and old age is the misuse of alcohol and of prescribed medication.

Sex: illegal drug-taking is more common in men. Misuse of prescribed drugs may be more common in women.

CAUSES Patients who develop problems with illicit drugs often have psychological and social contributory factors such as socio-economic deprivation, disordered personality, disturbed family background, membership of social groups in which drug-taking is prevalent, and ready availability of drugs.

Prescription drug misuse often comes from misguided medical prescribing for chronic neurotic or painful symptoms, which actually are rooted in the patientí personality.

A small minority of health professionals becomes addicted to narcotics and other substances (including anaesthetic gases, veterinary preparations) which they obtain at work.

PSYCHIATRIC AND PHYSICAL COMPLICATIONS A history of drug misuse is often found nowadays in young male patients presenting with serious mental illnesses such as schizophrenia and schizo-affective disorders. Such patients may be especially prone to violent behaviour. In some, the drug misuse appears to have triggered the psychosis; others have used the drugs as self-medication for their psychotic symptoms.

A typical case would be a young person with a chronic psychotic illness, precipitated and maintained by cannabis use. It may strike the patient as unfair that he should be advised against this drug, which his friends can perhaps take without ill ñeffect.

Government has also confused the issue recently, reclassifying cannabis to from class B to Class C in 2004, and issuing conflicting guidance as to how Police should deal with a person possessing it. In fact, it remains illegal and remains harmful, especially to psychiatric patients..

Medical complications, sometimes fatal, often arise from the intravenous injections of opiates and other drugs. They include infections (abscesses, phlebitis, septicaemia, hepatitis, endocarditis, pneumonia and HIV), and arterial occlusions leading to gangrene of limbs. Drug misuse in pregnancy may be teratogenic, and lead to complications with the pregnancy or birth. Poor diet and poor hygiene in drug misusers lead to various impairments of health.

LEGAL ASPECTS Chemicals with the potential for misuse can be classified according to their legal status:

• freely available: alcohol (see separate chapter), tobacco, caffeine, solvents.
• prescription-only: hypnotics, minor tranquillisers, opiates, anabolic steroids, anticholinergics especially procyclidine.
• illegal, for example cannabis, cocaine.

The Misuse of Drugs Act 1971 governs the production, distribution, prescribing and possession of certain drugs. The drugs controlled under this Act are divided into Classes A, B and C, with Class A drugs being most dangerous and carrying the most severe penalties for misuse. The Act also distinguishes Schedules 1 through 5, which govern the rules for possession, storage, prescription and keeping of records. Further details are given in the British National Formulary.

The legal status of a drug may not be an accurate reflection of its dangerousness. Alcohol and tobacco, which are legal and even socially encouraged in many settings, are possibly more threatening to life and health than some of the illegal substances considered in this chapter.

Much of the harm which comes with illegal drugs probably comes from the fact that they are illegal; if they were legalised and made commercially available, they could be taxed and regulated in the same way as presently legal substances such as alcohol.

There is a strong civil liberties argument for this course of action. It is fundamentally illogical for some types of mood-altering substance to be legal and others illegal. However, it seems unlikely that there will be the political will to tackle these anomalies in the immediate future.

PHARMACOLOGY Drugs which invite misuse fall into the following groups:

• Opiates.
• Depressants and tranquillisers, for example alcohol, barbiturates, chlormethiazole, benzodiazepines.
• Stimulants, for example cocaine, amphetamines, caffeine, khat.
• Hallucinogens (psychedelics, psychomimetics) for example LSD, mescaline, phencyclidine, psilocybin and psilocin (magic mushrooms).

Others include nicotine, cannabis, volatile inhalants, and various so-called ìdesigner drugsî such as for example ketamine and GHB. Many drug misusers take a mixture of drugs, the choice depending on availability, price and fashion as well as pharmacology.

PREVENTION Efforts to reduce supply are the province of police and customs.

Much effort and expense have been devoted to educational presentations to schoolchildren, given by drug advisory bodies or specialised police officers; such programmes are designed to prevent drug misuse but could have the opposite effect on some individuals. They have not been demonstrated to be effective.

Secondary prevention (harm minimisation) has benefits, see below.

TREATMENT While drug misuse can be seen as an illness requiring treatment, it is just as valid to regard it as a behaviour chosen by individuals, treatment for which will only succeed with the subjectís motivation and cooperation. The Mental Health Act 1983 specifically excludes compulsory detention or treatment for drug addiction per se, though the Act does apply to mental disorders which have been caused by substance misuse.

It was recently suggested that a new Mental Health Act in England and Wales would permit compulsory treatment of addictions per se, but this has caused great controversy, and the proposals are not yet clear at the time of writing.

Because of the large amount of drug-related crime, Drug Treatment and Testing Orders, DTTOs, have been introduced as community sentences for those addicted to heroin, cocaine or injecting amphetamines. A DDTO is essentially a probation order with a condition of treatment. The person has to agree, and they receive help to move away from drugs and crime. It is obviously a sensible idea , though its effectiveness is unclear.

The long-term aim of treatment may be either complete abstinence from drugs, or controlled drug use. Clients might be treated in dedicated inpatient settings, attend special outpatient clinics for controlled drug supplies, or consult community drug misuse teams staffed by specialised nurses and social workers with input from a consultant psychiatrist.

• Abstinence: if physical dependence is present, and the client elects to withdraw, initial treatment can be carried out in hospital or more frequently now in the community. This may include a detoxification. Withdrawal symptoms can be minimised by gradually reducing the dose of the drug, and perhaps substituting another less harmful drug which has cross-tolerance with the original.
  
• Relapse prevention Of psychological approaches to preventing relapse, most promising is the cognitive model which looks at situations and cues predisposing to resumption of drug use. A minority of addicts receive long-term rehabilitation treatment in residential units, which are often run on therapeutic community lines and require members to abstain from drugs completely.
• Controlled drug use: many users do not wish to give up drugs, and the treatment aim is therefore ìharm reductionî. Advice would include instruction on safer injection techniques, giving out clean needles to reduce needle sharing, and encouraging change from injected to oral drugs. Some teams adopt an ìassertive outreachî approach towards those drug users who lack the initiative to seek regular help for themselves.
• Physical complications often need attention, and many addicts have social difficulties or personality problems for which extensive and prolonged help may be given, to uncertain effect. There are no accurate statistics on outcome of treatment, and results must be considered in relation to the natural history of drug misuse as a behaviour of adolescence and young adulthood which tends to die away in later life.
  

Treatment services vary greatly around the country. Informal advice-based services are common, and may be run by a charity, a local authority or health services; community drug teams are often part of mental health services. Some GPs have developed a special interest in the area.

OPIATES Opiates include morphine, heroin, methadone, pethidine, buprenorphine and dipipanone. Opium and morphine are derived from the opium poppy, the others can be synthesised chemically.

Legal status and availability: strong opiates are Class A drugs but some weaker ones are available over the counter as codeine preparations or in cough syrup.

Most addicts obtain their supplies on the black market but a few cases are iatrogenic due to inappropriate prescribing.

Administration: used to be mostly intravenous, but since awareness of HIV, is more frequently by smoking (ìchasing the dragonî).

Psychological and social effects: intravenous injection may produce either intense pleasure or malaise. Chronic opiate use leads to apathy, moodiness, and clouding of consciousness. Addictsí social circumstances deteriorate, and the need to obtain the drug dominates their lives.

Physical effects: nausea, constipation, constricted pupils are seen in the acute stages. Large doses cause respiratory depression and death, for example by injection of a stronger than usual supply, or resumption after release from prison of a previous high dose when tolerance has worn off. Chronic use produces a characteristic greyish skin colour, with weight loss and flat affect.

Intravenous use may cause medical complications as above. Use in pregnancy is associated with obstetric complications: abrupt opiate withdrawal can cause intra-uterine death, and opiate use at term causes respiratory depression and withdrawal symptoms in the baby. Management of the pregnant opiate user should include gradual withdrawal in the second trimester if possible, with close cooperation between all the professionals concerned.

Tolerance and dependence: greatly increased tolerance, and physical dependence, develop within a few weeks of starting regular use. Endorphin neurotransmitters are probably involved. There is a severe withdrawal syndrome consisting of craving, sleepiness, rhinorrhoea, lacrimation, abdominal colic and diarrhoea.

Detection: opiates can be detected by blood and urine tests.

Treatment: there is a legal requirement for all doctors to notify the Home Office Drugs Branch, Queen Anneís Gate, London SW1H 9AT, of opiate addicts with whom they come in contact.

Overdose should be managed as a medical emergency; treatment may include the opiate antagonist naloxone to reverse respiratory depression.

Other management depends on whether the patient wishes to become abstinent or not. If they do wish to get off, they will be helped either by gradually reducing the dose or by a detoxification. For those who elect to withdraw, clonidine or lofexidine may be given.

The antagonist naltrexone can be used for help in relapse prevention, but its effectiveness is unclear.

Most users prefer, at least initially, to stay on opiates, so harm reduction programmes are the mainstay. Methadone maintenance is key; the patient is prescribed a legal supply of opiate, in oral (liquid) form. This is designed to satisfy cravings, and reduce the need for purchasing of illegal supplies, with associated crime in order to finance this. Oral administration can be observed if necessary, if there are concerns the patient is selling his supply (this is usual in other countries, though less frequent in the UK),. Oral administration is also the safest route of ingestion.

If the patient can be stabilised on methadone, and develop a good relationship with the clinic, his lifestyle and health may improve, and he may eventually consider gradual reduction in dose and abstinence. There is evidence that methadone as part of a maintenance programme ìcan reduce the use of heroin in dependent people, and keep them in treatment programsî.

Buprenorphine sublingual is an alternative to methadone. Maintenance prescriptions of diamorphine or dipipanone also have their proponents, but these are in a minority. They can only be issued by doctors with a special licence, working from a treatment centre, and it is advisable for the prescriptions to be dispensed from a designated pharmacy. (Note: any doctor may prescribe diamorphine for relief of severe pain.)

For those who continue to inject, many chemists provide sterile needles free of charge under the ìharm reductionî policies designed to restrict spread of HIV and other infections.

Prognosis: some opiate addicts give up their habit either spontaneously or with medical help. The prognosis is not inevitably one of remorseless progression to needle-sharing and death. Mortality is increased several-fold, of the order of 2% per annum; the most frequent causes of death are respiratory depression from drug overdose, infections, and suicide. Often, patients who reduce opiate use move towards misuse of other substances, notably alcohol.

AMPHETAMINES (SPEED) Legal status and availability: injectable amphetamines are Class A, and oral amphetamines Class B drugs. They used to be widely prescribed for depression (in the 1950s and 1960s) and for obesity (until quite recently). They are stimulants, and are thus related to cocaine (see below).

They are now only licensed for treatment of attention deficit hyperactivity disorder (ADHD) in children and adolescents as part of a comprehensive treatment programme, and for narcolepsy or obstructive sleep apnoea syndrome.

Private prescription by ìslimming clinicsî still occurs occasionally, and patients sometimes get supplies over the internet. Easy chemical synthesis also makes for continued widespread availability.

Administration: oral, intravenous or inhaled.

Psychological effects: amphetamines are stimulants which cause euphoria, increased activity, insomnia and anorexia. Amphetamine psychosis consists of visual or auditory hallucinations with paranoid delusions, similar to paranoid schizophrenia. (As amphetamines act by stimulation of CNS dopamine systems, this effect is a main plank of the ìdopamine hypothesisî of schizophrenia.)

Amphetamine psychosis nearly always recovers quickly if the drug is withdrawn.

Physical effects: stimulation of sympathetic nervous system activity.

Tolerance and dependence: psychological dependence and tolerance occur but probably not physical dependence. Depressed mood, low energy and increased sleep may follow withdrawal.

Detection: amphetamines can be detected by blood and urine tests.

Treatment: various medications have been tried, but none is generally accepted as helpful. Individual support or group therapy, concentrating- in the absence of physical dependency- on relapse prevention are more important.

COCAINE AND CRACK Cocaine is derived from the coca shrub grown in South America. Crack is cocaine which has been separated from its hydrochloride salt.

Legal status and availability: cocaine is a Class A drug, not used in medical practice except in ENT and related surgery (to control bleeding by its vasoconstrictive actions- hence its necrotizing effects on the nasal septum).

Administration: inhaled as snuff or injected. Crack can be smoked to produce a rapid effect.

Psychological effects: similar to those of amphetamine. Cocaine psychosis resembles the amphetamine psychosis but also includes tactile hallucinations consisting of a sensation of insects crawling on the skin (formication).

Physical effects: cocaine may cause cardiac arrhythmias. Repeated inhalation may cause perforation of the nasal septum.

Tolerance and dependence: only psychological dependence occurs with ordinary cocaine, but crack is considered to be more addictive and tolerance rapidly develops- there may possibly be physical dependence, but this is controversial.

Detection: cocaine can be detected by blood and urine tests.

Treatment: addicts should be notified to the Home Office. Maintenance prescriptions can only be issued by doctors with a special licence. Because of the lack of a physical withdrawal syndrome, no specific treatment of withdrawal is indicated. Most users stop- and many do, or at any rate drift in and out of using- without medical attention.

CANNABIS (INDIAN HEMP, HASHISH, POT) Cannabis is the name given to products of the plant Cannabis sativa, which include hashish and marijuana. ìSkunkî is an especially potent form. The psychoactive ingredient is tetrahydrocannabinol (THC). Cannabis sativa grows wild in many countries including Britain. THC can also be chemically synthesised.

Legal status and availability: cannabis is a Class C drug, but freely available from unofficial sources and probably used by at least 10% of young people in this country. Legalising cannabis has been suggested, but this would have adverse consequences for psychiatric patients because of its propensity to cause and worsen psychosis.

Administration: cannabis is usually mixed with tobacco and smoked, but can also be taken orally or intravenously.

Psychological and social effects: cannabis usually produces sedation, but can exaggerate an unpleasant pre-existing mood state of anger, depression or anxiety. Psychotic symptoms including perceptual distortions, visual hallucinations and confusion can occur. The use of cannabis is often implicated in worsening the clinical course of schizophrenia, precipitating onset or relapse and retarding recovery. Sustained long-term use is believed to cause an ìamotivational syndromeî of apathy and cognitive defects, partially reversible if the drug is stopped.

Physical effects: cannabis has many physiological effects, including cardiovascular ones which may be dangerous in people with heart disease. Cannabis taken in pregnancy is thought to be teratogenic. Chronic effects include those of the associated tobacco smoking. Cannabis has analgesic and other properties which have been subject of trials, for example in multiple sclerosis, but as yet it has not been considered to be an improvement on existing treatments.

Tolerance and dependence: psychological dependence is common

Physical dependence: probably does not occur.

Detection: cannabis can be detected in body fluids for up to two weeks after consumption.

Prognosis: occasional cannabis use may be harmless in some people, despite the concerns about psychotic illness described above. However, cannabis predisposes indirectly to use of more dangerous drugs through encouraging contact with other drug users.

LYSERGIC ACID DIETHYLAMIDE (LSD, ACID) LSD is a synthetic compound. It is a hallucinogen. Such drugs became well-known in the 1950s, when Aldous Huxley, a writer of the time, foolishly publicised his subjective impressions of taking mescalin.

This contributed to their use and abuse by the impressionable, and they were made illegal in the late 1960s. They were used in abortive experiments on psychiatric patients, some of whom later claimed that they had been harmed thereby.

Legal status and availability: LSD is a Class A drug, easily synthesised by amateur chemists.

Administration: oral. It is often sold soaked into blotting paper.

Psychological effects: perceptual distortion, reactivation of distant memories, extreme depression or ecstasy (ìbad tripsî or ìgood tripsî), acute psychotic experiences. Death can result, for example from delusions of being able to fly from high places. ìFlashbacksî of LSD-induced experiences may continue for years after the last dose.

Physical effects: those of sympathetic nervous system overactivity.

Tolerance and dependence: do not occur.

MDMA (ECSTASY) MDMA (3,4, methylenedioxyamphetamine) is a Class A drug which alters perceptual and emotional experience, giving enhanced appreciation of colour and sound and increased empathy with others, and also has stimulant properties.

It is popular at pop festivals and ìraveî parties, but may cause sudden death in such settings through cardiac arrhythmia, dehydration and hyperthermia. The acute intoxication may resemble neuroleptic malignant syndrome or serotonin syndrome. It may precipitate or cause psychosis. Long-term use may have neurotoxic effects. Tolerance may develop.

GLUES AND SOLVENTS Fumes from products based on toluene and acetone have been increasingly used for their psychological effects in recent years. Such products include glues and solvents for domestic or industrial use. They are freely available and popular among children, particularly male adolescents.

Administration: inhalation from paper, bottle or bag (glue-sniffing).

Psychological effects: euphoria and perceptual disturbance, progressing to stupor. Long-term neuropsychological damage may occur.

Physical effects: these substances are toxic to the liver, kidney, heart and brain, and inhalation may cause accidental death. Chronic use causes an acneiform rash around the mouth and nose.

Tolerance and dependence: psychological dependence is common, but tolerance and physical dependence probably do not occur.

Treatment Abstinence is the goal here,

TOBACCO Nicotine is the constituent of tobacco which causes psychological effects and dependence, whereas carbon monoxide and tar cause the physical ill-effects. Cigarette smoking is more harmful than other forms of tobacco consumption. About one-third of the population smoke and rates are rising among young women. Smoking is widespread among patients and staff in psychiatric services.

Psychological effects: nicotine is both a central nervous system stimulant and an anxiolytic.

Physical effects: acute effects are those of sympathetic nervous system overactivity. Chronic effects include raised susceptibility to lung cancer and many other cancers, cardiovascular disease, chronic bronchitis and, during pregnancy, stillbirth and abortion.

Tolerance and dependence: both psychological and physical dependence occur. There is a withdrawal syndrome consisting of anxiety, depression, irritability, insomnia and craving.

Management: nicotine chewing-gum is a less toxic alternative which helps some smokers give up. Psychological methods including hypnosis and group therapy are sometimes effective.

Prevention: It would be better to prevent people from ever starting to smoke, through education in schools, banning advertisements, and increasing the price of cigarettes. There are moves to ban smoking in public places in the UK, a move which has already happened in Ireland and some other countries. Although it may seem an attack on civil liberty, the rights of non-smokers must also be respected, and a ban now seems inevitable at some stage.

Psychiatric inpatients are very often heavy smokers, however, and it is unclear how their rights are to be safeguarded.

CAFFEINE Caffeine, a xanthine alkaloid, is a constituent of coffee, tea, cocoa, and cola beverages. Most people in the UK consume several such drinks a day without apparent ill-effects.

Psychological effects: caffeine is a stimulant which increases well-being and reduces fatigue. Large doses cause anxiety and insomnia. ìCaffeinismî is an important differential diagnosis of anxiety disorders. Some psychiatric patients consume large amounts (say 10 or 20 cups of tea or coffee daily) in the mistaken belief that this helps to calm their nerves.

Physical effects: tachycardia, diuresis, muscle tension.

Tolerance and dependence: psychological but not physical dependence occurs.

BARBITURATES

Legal status and availability: barbiturates used to be widely prescribed as tranquillisers and hypnotics before their addictive potential became clear. Their prescription for this purpose is now almost extinct, though a very few older people may remain dependent. Barbiturates are still sometimes used for epilepsy. Black market barbiturates are less frequently used today.

Administration: oral or intravenous.

Psychological effects: central nervous system (CNS) depression causing psychomotor impairment, drowsiness or sleep.

Physical effects: ataxia, nystagmus, slurred speech. Large doses may cause fatal respiratory depression. Cross-tolerance with alcohol and anaesthetics exists.

Tolerance and dependence: tolerance and physical dependence develop rapidly. There is a withdrawal syndrome of anxiety, insomnia, tremor, fits and delirium.

Detection: barbiturates can be detected by blood and urine tests.

BENZODIAZEPINES Misuse has been an important problem: to some extent, they can be seen to have replaced the barbiturates as an over-prescribed sedative for the ups and downs of life, though with less serious side effects (that is, lack of respiratory depression leading to safety in overdose). They act at receptors which are associated with gamma-aminobutyric acid (GABA) receptors.

The BNF carries a sensible withdrawal schedule (about 1/8 th of the daily dose reduced per fortnight) (ref 4) for patients who have become dependent.

Further detail about therapeutic use of these drugs is in that chapter.

OTHER RESOURCES

1. Department of Health guideline on treatment. http://www.dh.gov.uk/assetRoot/04/07/81/98/04078198.pdf
2. Resources and information http://www.drugscope.org.uk
3. Society For The Study Of Addiction http://www.addiction-ssa.org