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Drugs of Abuse and Addiction

Dr Paul D Miller, MB BCh,MRCPsych, Consultant Psychiatrist, Cherry Knowle Hospital, Sunderland.

Introduction

Throughout human history, most societies have made use of one psychoactive substance or another. Frequently, one substance would be regarded as legitimate while all others were severely discouraged. Tea was described as a "deadly poison" by 19th century English physicians (RCPsych, 1986), yet until 1868 opium and cannabis could be legally purchased and opium was grown in parts of England for much of the 19th century. A Governmental Commission on cannabis and Royal Commission on opium each concluded in 1894 and 1895 that the usage of these substances was not a cause for concern.

Tolerance occurs when, as a result of biochemical adaptation to a drug, the individual needs to take increasing amounts to obtain the same effect. This is physical dependence. Psychological dependence on the other hand, is a psychological need to use a drug such as alcohol to relieve symptoms such as loneliness or anxiety. As the individual becomes increasingly physically dependent upon a drug they are likely to suffer withdrawal symptoms if they stop or significantly reduce their consumption.

Drug Abuse

Doctors working in primary care may have to deal with problem drug use for a number of reasons. There may be patients who have become addicted to legitimately prescribed drugs such as benzodiazepines or, less commonly, barbiturates. Some patients may be receiving treatment for addiction to illegal drugs. A third group may present, perhaps as temporary residents, requesting prescriptions for controlled drugs, often giving histories suggestive of conditions such as renal colic. Others may present with a medical complication of drug use, such as an abscess or thrombosis.

In each case, the general practitioner will need to feel confident to deal with the episode and where appropriate to initiate a suitable management plan.

Patients who are addicted to benzodiazepines will suffer a withdrawal syndrome if the dose is stopped or reduced too rapidly. Symptoms may include anxiety, palpitations, headaches, insomnia, sweating, tremor, pains and altered perception. Management requires a slow reduction in dosage of benzodiazepine, preferably agreed with the patient. This may be aided by management of any anxiety and a generally supportive approach.

Patients who become addicted to illegal drugs, including illegally obtained benzodiazepines, may be in employment but many are not and lead extremely chaotic, disordered lives which revolve around their drug taking and acquiring behaviours. Since addiction to illegal drugs is expensive, burglary of property and theft from cars is common, as is prostitution among female addicts.

Opiates

The most commonly abused opiate is heroin which rapidly produces dependence and tolerance with regular use. It has a strong euphoriant effect particularly when used intravenously. It also causes constipation, lowered appetite and libido, drowsiness and respiratory suppression. This may be fatal in overdose or in those who have abstained and lost their tolerance then restart usage at their previous dose.

Withdrawal symptoms are rarely serious but cause a strong urge to take more heroin. They include a craving for the drug, diarrhoea, dilated pupils, musculoskeletal pains, "goose flesh", tachycardia and agitation. They peak after one to two days and pass off after a week or so.

Deaths among heroin addicts occur as a result of overdose and medical complications such as infection and thrombosis. An increasingly important factor is the spread of HIV among those sharing needles.

There are several approaches used in the management of heroin addiction. Individuals with sufficient motivation may be offered a withdrawal regime. If the withdrawal is done rapidly then symptoms such as diarrhoea may be controlled by a drug such as "Lomotil" with an anxiolytic for agitation and restlessness. If the dosage of heroin is high then methadone linctus may be used gradually to wean the patient off opiates. Methadone causes similar withdrawal symptoms to heroin but has a longer half life and may be given once a day since withdrawal symptoms develop after about 36 hours. The initial dose of methadone must be chosen with great care, since addicts may overstate their heroin usage to obtain extra supplies which may be sold. Alternatively, they may be afraid of being prescribed a dose which will not keep their withdrawal symptoms at bay. Further, the purity of street heroin varies considerably around the country and from time to time.

Addicts who lack the motivation to withdraw from using opiates may be prescribed maintenance methadone, depending on local policy. In this case, it is important to beware of those who seek to gain supplies from more than one source. Maintenance is often considered in terms of "harm reduction". Providing regular, safe supplies of methadone removes the addict from the need to mix with other addicts and dealers to obtain their supplies. This may help them to break out of the drug taking lifestyle. In addition, it removes the risks of supplies contaminated with the various substances which are used to "cut" street drugs. It prevents the need to indulge in criminal activity to pay for drugs, in particular petty prostitution with its attendant health risks including the spread of HIV. Some units offer a needle exchange which supplies clean needles to those addicts who continue injecting, to prevent the spread of infectious diseases, including HIV and hepatitis, caused by the sharing of needles.

Whatever approach is taken, it is important to establish a therapeutic relationship with the patient to gain their trust and be able to carry out worthwhile psychological work aimed at making the patient's life more normal and less drug centred.

Sometimes the most difficult aspect for the patient is to reconstruct their life away from the drug scene and their drug taking friends. Rehabilitation aims to provide activities and support for patients as they take gradually more responsibility for their own lives and behaviour whilst receiving input and support from individuals experienced in dealing with the problems of drug users.

Benzodiazepines

Benzodiazepines can produce dependence in only a few weeks with regular use. Patients may become addicted to prescribed drugs or may obtain their supplies from "street dealers". Cessation of the benzodiazepine may produce a withdrawal syndrome with anxiety, insomnia, reduced appetite and weight, perceptual disturbances and tremor. This may be difficult to distinguish from the original condition for which the benzodiazepine was prescribed. Severe withdrawal syndromes may result in convulsions, confusion or psychosis.

Where the patient is unable to stop the benzodiazepines because of withdrawal symptoms, it is often best to convert their total dosage to the equivalent of diazepam, which has a long half life and therefore results in fewer withdrawal symptoms breaking through between doses. The dose of diazepam should then be reduced gradually by 10% (DoH, 1991) or 2 to 2.5 mg every two weeks. If withdrawal symptoms emerge then the program of reduction should be slowed further. Complete withdrawal may take as long as a year.

Volatile substances

Abuse of volatile substances is commonest among teenage boys, often in groups. The scale of the problem is unknown though it seems to be common. Substances inhaled include glues, solvents, aerosols, the contents of fire extinguishers and butane.

Deaths may result from asphyxia if a plastic bag is used, fires and explosions when used in confined spaces, accidents such as drowning and falls while intoxicated, aspiration of stomach contents and toxic effects such as cardiac arrest from butane. Additionally, some substances can cause severe neurotoxicity.

Withdrawal symptoms occur rarely, if at all, but psychological dependence may occur. Referral to either a child psychiatry service or social services will usually be the most appropriate form of specialist help.

Cannabis

Cannabis, also known as dope, pot, hash, grass, comes from the plant Cannabis sativa. Marijuana is made from the flowers and vegetation of the plant whilst the resin produces hashish. It can be smoked, eaten or made into cakes which are then eaten. It mostly seems to exaggerate the pre-existing mood of the user. There is little evidence for either a withdrawal syndrome or physical dependence, though psychological dependence may occur. It has been suggested that cannabis can cause a psychosis but this remains a controversial subject.

The use of cannabis is certainly very widespread but most users do not move on to other drugs.

Amphetamines

Amphetamines, also known as speed, produce euphoria and are not uncommonly injected intravenously. They cause sleeplessness, anorexia and a feeling of having much energy. As such, they are sometimes abused by those who need to work or study for long periods of time.

The withdrawal symptoms are generally mild with insomnia, decreased energy and sometimes depression. Psychological dependence is common, and heavy use can cause a psychosis similar to schizophrenia.

A suspicion of amphetamine use can be confirmed by urine testing. Detoxification regimes are not needed, sudden withdrawal being safe, as long as the patient is monitored for depression and treated with antidepressants if necessary.

LSD

LSD (lysergic acid diethylamide) is a hallucinogen. It causes sensory distortions including an altered perception of time, and a "crossing" of sensory functions such that colours are "heard" or sounds are "seen". A complete "trip" may last around twelve hours. Flashbacks may occur, where the user reexperiences the drug trip weeks or even months later. This can be very frightening to the patient and may cause much anxiety.

The physical effects of LSD are quite mild, with elevated heart rate and dilated pupils. Tolerance may occur but not withdrawal symptoms or physical dependence.

After widespread use in the 1960s, LSD became less common, before re-emerging recently in association with the rave scene.

Cocaine

Cocaine is a stimulant and results in similar effects to amphetamine. Additionally, inhalation can cause perforation of the nasal septum. Paranoid psychosis may also occur as may formication, a sensation like insects moving under the skin. It is strongly psychologically addictive. Crack is a highly addictive concentrated form of cocaine which is smoked, sometimes in special apparatus.

Ecstasy

Ecstasy has become very widely abused in recent years, particularly amongst large groups of teenagers in association with the music and dance scenes. It is a hallucinogenic amphetamine which can also cause euphoria, a sense of well-being, perceptual changes. It can also result in depression after use and some deaths have occurred as a result of heat-stroke and dehydration. Ecstasy can produce psychoses, visual hallucinations, depression, panic attacks and chronic depersonalisation, (McGuire, Cope & Fahy, 1994)

REFERENCES

 

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