Introduction

Alcohol is the most popular of the psychoactive substances available for recreational use. In small quantities it has a stimulating effect, lifting the mood and causing disinhibition, but if larger amounts are taken sedation and depression result. Concentration, speech and movement are also affected. Behaviour after drinking large amounts of alcohol is often impulsive, ill-judged and may be aggressive. As a consequence alcohol can be an extremely damaging drug. Regular heavy drinkers can suffer devastating physical, mental and social damage, and their families are also profoundly affected. Alcohol is implicated in 40% of all road traffic accidents, 50% of murders and 80% of suicides. In very large quantities it can be fatal because it depresses brain centres controlling circulation and breathing.

About 90% of the adult population drinks alcohol at some time. There is a continuum between normal social drinking, problem drinking and dependence on alcohol, and it can be difficult to distinguish between these states (Fig. 1). Maximum ‘safe’ levels of consumption have been recommended, above which the risk of sustaining some social or physical damage rises considerably. These levels are 21 units per week for men, and 14 per week for women (Fig. 2). At least 25% of men and 15% of women exceed these quantities. About one in ten of these will experience some significant difficulties in their physical or mental health, relationships, ability to work or some other aspect of their lives. Twenty percent of all admissions to psychiatric units are for alcohol-related problems.

Fig. 1 Continuum of alcohol consumption.

Fig. 2 Units of alcohol.

Clinical features

The main characteristic of dependence on alcohol is that the drinking takes priority over all other aspects of life. The threat of a marital breakdown or unemployment is not enough to convince the dependent drinker to cut down or stop, instead they will continue to drown the sorrows that have been produced by the alcohol in the first place. Other typical features of dependence on alcohol include:

Feeling compelled to drink. There is such a strong desire to drink that alcoholics often feel they have no control over their drinking behaviour, and if alcohol is not available it is craved for. Many dependent drinkers want to stop but feel they cannot.

Tolerance of the effects of alcohol. Increasing quantities are required to produce the same effect.

Withdrawal symptoms which appear within 6 hours of the last drink. Typically this occurs overnight, resulting in withdrawal symptoms first thing in the morning. The earliest symptom to occur is usually tremor. If alcohol is not drunk quickly other symptoms follow, including anxiety, agitation, nausea, vomiting and sweating. Generalised convulsions can occur, and one in 20 will develop delirium tremens (DTs). Withdrawal symptoms can continue for up to a week if untreated.