Drug abuse and addiction

Written by Dr John Powell, MRC Psych, specialist registrar

What is drug abuse and addiction?
Drug abuse refers to the use of a drug for purposes for which it was not attended, or using a drug in excessive quantities. Drug addiction is a state of physical or psychological dependence on a drug.

Physical addiction is characterized by the presence of tolerance (needing more and more of the drug to achieve the same effect) and withdrawal symptoms that disappear when further medication is taken.

All sorts of different drugs can be abused, including illegal drugs (such as heroin or cannabis), prescription medicines (such as tranquilisers or painkillers), and other medicines that can be bought off the supermarket shelf (such as cough mixtures or herbal remedies).

What causes drug abuse and addiction?
This depends on the nature of the drug being abused, the person taking the drug and the circumstances under which it is taken.

Some medications - for example certain sleeping pills or painkillers - are physically addictive. They have a specific effect on the body which leads to tolerance and withdrawal symptoms. Others may lead to a psychological addiction if people have a craving for the effect that the drug causes.

There has been some speculation that some people may be more prone to drug abuse and addiction than others. Research is being carried out into whether there may even be genes that predispose certain people to addiction.

Social circumstances are important in drug abuse. Peer pressure, emotional distress and low self-esteem can all lead individuals to abuse drugs. Ease of access to drugs is another influence.

People abuse drugs for a reason. Understanding what the person's motivation is helps to explain why that person is abusing drugs.

How is drug addiction treated?
The first step in treatment is recognition by the individual that they have a problem.

The person's GP will be able to advise on treatment for drug addiction. He or she may suggest that they see a specialist.

Effective treatments are tailored to the needs of the individual. There is no one therapy that is used in all cases. The choice of treatment will also depend on which drug is being abused.

Treatments include psychological therapies, such as behaviour therapy and medication to help the individual's withdrawal symptoms.

Specific areas that may be focussed on during treatment include:

detoxification (coming off the drug if physically addicted)

preventing relapse

coping with relapse

longer term rehabilitation.

Key sources of evidence
Leshner AI. Science-based views of drug addiction and its treatment. Journal of the American Medical Association. 1999;282:1314-1316.

US National Institute on Drug Abuse. Principles of drug addiction treatment - a research based guide. US National Institutes of Health. 1999.February 2000.