A drug is a chemical substance that acts on the brain and nervous system, changing a person’s mood, emotion or state of consciousness.
Drugs are often classified by the effect they have.
- Stimulants, such as cocaine, make people feel full of energy.
- Depressants (or sedatives), such as heroin, make people feel relaxed.
- Hallucinogens, such as LSD, make people see, feel or hear things that are not real.
Drug misuse is when a person regularly takes one or more drugs to change their mood, emotion or state of consciousness.
Addiction
One of the biggest risks of drug misuse is that you can develop a drug addiction. There are two main types of drug addiction:
- Physical addiction, when there are withdrawal symptoms, such as nausea, vomiting or cramping, if the supply of the drug is suddenly withdrawn.
- Psychological addiction, when there is a psychological compulsion or need to regularly use a drug. If the drug is withdrawn, there are no physical symptoms but there may be psychological symptoms such as depression, anxiety and irritability.
Legal drugs
Under British law, most drugs are illegal. However, some drugs are legal, including:
- caffeine,
- alcohol, and
- cigarettes.
If a drug is legal, that does not mean it is harmless. In England each year, cigarettes and alcohol kill more people than all illegal drugs put together.
Prescription medication, such as strong painkillers or tranquillisers, is often misused by people who have no clinical need for it but use it for its mood-altering effects.
In many cases, it is illegal to posses certain types of prescription medication, such as morphine or methadone, without a valid prescription.
Risks to health
As well as the danger of addiction, drug misuse has serious health risks and is associated with a wide range of conditions and complications, both physical and psychological.
For example, cocaine can cause heart failure and heroin can cause respiratory failure (loss of normal lung function), both of which can be fatal. Each year in England and Wales, an estimated 2,000 deaths are caused by illegal drug abuse.
If a person uses a needle to inject drugs, they have a high risk of catching a serious blood-borne infection, such as HIV or hepatitis C.
The Department of Health estimates that, in England, 90% of all cases of hepatitis C and 6% of all HIV cases are caused by injecting drugs.
