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Drugs misuse

Drug addiction is when you become dependent on a drug and it forms a central part of your life. The misuse of drugs can lead to physical dependency or psychological dependency.
Brought to you by NHS Choices.

Physical dependency

Physical dependency means that your body has become so used to a drug that you get physical withdrawal symptoms if you stop taking it. This means that you have to keep taking the drug to stop yourself feeling ill.

Psychological dependency

Psychological dependency means that you take the drug because it has formed a large part of your life, and you take it to make yourself feel good. You may feel that you cannot stop taking the drug, even though you are not physically dependant. Some drugs can make you both physically and psychologically dependent.

As you take more of a drug, your body becomes tolerant to it so it does not have such a strong effect. This means that you need to take larger amounts to get the same effect as when you started taking it.

Drug misuse

Drug misuse is when you take illegal drugs, or when you take medicines in a way not recommended by your GP or the manufacturer. Taking medicines in very large quantities that are dangerous to your health is also an example of drug misuse.

Examples of drugs that are commonly misused include:

  • illegal drugs,
  • alcohol,
  • tobacco,
  • prescribed medicines including painkillers, sleeping tablets, and cold remedies,
  • khat (a leaf that is chewed over several hours), and
  • glues, aerosols, gases and solvents.

Illegal drugs are drugs that have been banned, by law, for use in this country. It is illegal to possess or supply banned drugs.

Some illegal drugs have been categorised as prescription-only, meaning that they may only be used legally if prescribed by a doctor, but are illegal to use, possess, or supply, in any other circumstances. Illegal drugs are categorised into three classes: A, B and C.

Class A drugs

Class A drugs are considered to be most dangerous to health. They include:

  • cocaine (including crack; nicknamed charlie, coke, snow),
  • dicanol,
  • heroin (nicknamed smack, H, gear, scag, brown),
  • LSD (lysergic acid diethylamide; nicknamed acid, trips, blotters, tabs),
  • mescalin,
  • methylamphetamine (crystal meth),
  • methadone,
  • morphine,
  • opium; PCP (phencyclidine; nicknamed angel dust),
  • pethadine,
  • poppy straw,
  • psilocybin,
  • STP (amphetamine; nicknamed serenity, tranquility and peace),
  • magic mushrooms (nicknamed liberties, shrooms), and
  • DMA (methylenedioxymethamphetamine; nicknamed ecstasy, E, pills, XTC, disco biscuits, Mitsubishis, Rolexs, dolphins).

Class B drugs

Class B drugs are also considered to be dangerous, but less so than class A drugs. They include:

  • amphetamine (an ingredient of ecstasy; nicknamed speed, whizz, dexies),
  • codeine (in concentrations above 2.5%),
  • DF118 (dihydrocodeine),
  • ritalin, and
  • barbiturates.

Class C drugs

Class C drugs are considered to be the least harmful to health but they are still illegal to possess and give or sell to other people. They include:

  • cannabis, cannabis resin and cannabinol (marijuana, grass, pot, weed),
  • methaqualone,
  • anabolic steroids (nicknamed roids),
  • ketamine (nicknamed special K, vitamin K, green),
  • GHB (gammahydroxybutrate; nicknamed GBH, liquid ecstasy and sometimes referred to as date-rape drugs), and
  • benzodiazepines including valium, and rohypnol (nicknamed roofies and sometimes referred to as date-rape drugs).

Some of these drugs are legal when prescribed by a doctor and can be used for pain relief or to relieve the symptoms of certain medical conditions.

Illegal drugs are classified under the Misuse of Drugs Act 1971, which can only be changed and added to by the Home Secretary.

If you are taking prescription medication, you should always follow the manufacturer’s advice about driving. Never drive after taking medication where the manufacturer advises against driving and operating heavy machinery. Ask your GP if you are unsure.

See the ‘useful links’ section for more information about medication and driving.


Taking illegal drugs carries many serious health risks because they are not controlled or supervised by medical professionals. Many illegal drugs have to be imported into this country from different parts of the world.

This means that they have been processed and passed through the hands of many different people before they are eventually sold in small quantities on the street. During this time, they may be mixed with other products (cut), often many times, to increase the quantity and make more profit.

Drugs that contain other substances can be very harmful

It is not unusual to find substances in illegal drugs that are much more harmful than the drugs themselves. Someone buying illegal drugs may trust their own supplier, but they cannot know or trust the chain of people who have dealt with the drugs before that.

As well as having immediate health risks, some drugs can be addictive and lead to long-term damage to the body. Heavy or long-term use of some illegal drugs may cause the user to overdose, which may cause permanent damage to the body and can be fatal.

Mixing drugs is very dangerous

Mixing drugs is also highly dangerous. For example, a speedball (a mixture of cocaine and heroin) increases the risks from each drug involved, making it far more likely for the user to experience harmful side effects.

Taking illegal drugs also carries a legal risk. Being caught in possession of class A drugs may carry a penalty of seven years imprisonment, while supplying class A drugs can mean life imprisonment.

Sentences for supply and possession of class B and class C drugs can be similar. Supplying means giving or selling drugs to other people. Even giving small amounts of drugs to friends can be classed as supplying drugs, even if no money is involved.

The health risks of using specific illegal drugs are:


Short-term effects include:

  • dizziness and sickness,
  • dry mouth, lips and tongue,
  • panic and paranoia (when you are suspicious of people and situations),
  •  feeling hungry, and
  • loss of coordination.

If you use cannabis on a regular basis, long-term effects can include:

  • lung disease and lung cancer,
  • respiratory problems such as bronchitis and asthma,
  • high blood pressure, and
  • infertility.

There is some evidence that cannabis can also cause some mental health conditions such as depression and schizophrenia. About 10% of people who smoke cannabis become addicted to it.

Amphetamines (speed)

Amphetamine use can lead to:

  • short-term dizziness,
  • hallucinations,
  • burst blood vessels which can, in very rare cases, lead to paralysis and may even be fatal,
  • insomnia, and
  • depression.

As your body becomes more tolerant to the drug, you need to take larger amounts to produce the desired effect. This increases both health risks and the likelihood of dependence or addiction. Some people may also have a toxic or allergic reaction to amphetamines.

Ecstasy (MDMA)

Very few ecstasy tablets are pure. Most have been mixed with other contents such as talcum powder and even dog-worming tablets. Most dangerously, anaesthetics and tranquillisers such as ketamine may also be added to ecstasy tablets.

Another big risk with ecstasy is dehydration. Ecstasy raises your body’s temperature and the amphetamine contained in each tablet encourages you to behave energetically for long periods of time, for example dancing in a club all night.

If your fluid levels drop dramatically, dehydration can cause unconsciousness, coma and even death. There have been over 200 ecstasy-related deaths in the UK since 1996.

If you take large amounts of ecstasy, you can experience feelings of anxiety, panic and confusion, so it’s difficult for other people to calm you down. Other unpleasant side effects include:

  • dry mouth,
  • nausea,
  • raised blood pressure, and
  • depression.

Some users say that their body tends to stiffen after taking ecstasy, often causing them to clench their jaw and grind their teeth. The feeling that the heart is hammering or pounding in the chest is another common symptom.

Cocaine and crack

Cocaine raises blood pressure, causes the heart to beat irregularly and increases body temperature. As well as causing heart failure when taken in large doses, long-term use of cocaine can lead to:

  • extreme paranoia,
  • depression,
  • insomnia,
  • extreme weight loss and malnutrition, and
  • impotence in men.

Because cocaine is so addictive, users experience withdrawal symptoms such as intense irritability and restlessness if they go for longer than usual without taking it

This period of time becomes shorter and shorter as the body becomes more tolerant to the drug and requires larger quantities to experience a high. As the effects of the drug wear off, users will get symptoms such as exhaustion and depression.

Women who use cocaine while they are pregnant risk the health of their babies, as the drug can cause low birth weight and birth defects. Their baby may also be born addicted to it.

People who are addicted to cocaine or crack often lose more than just their physical health, as the addiction encourages anti-social behaviour such as moodiness, unpredictability and crime in order to fund their habit.

LSD (acid)

Taking acid is risky because each tab can contain very different amounts of acid. Research shows that a single tab can have as little as 25 micrograms of acid in it, or as much as 250 micrograms - this is enough to cause serious side effects.

Psychological health problems are the most common side effect of taking acid. A bad trip can feel like being trapped in a nightmare, often played over and over. A trip is the name given to the hallucinatory effects caused by some drugs.

Flashbacks can occur at any time after taking acid, sometimes even after many years. A flashback is a sudden, vivid memory of a bad trip and can be very frightening, and can sometimes cause mental health problems. There is no way to prevent flashbacks occurring.

When a person has taken acid they will experience hallucinations and delusions. This is dangerous as they may behave irrationally, believing, for example, that they can fly. Acid users who have a bad trip often try to physically run away from the experience. If this happens, they could put themselves in a dangerous situation by running into a busy road for example.


Most heroin bought on the street is only 10-60 % pure. It is usually mixed with other products to increase the quantity and therefore make more profit from it. It is often the substances used to bulk up heroin that prove most harmful and cause allergic or toxic reactions. Users can never be sure that the heroin they buy has not been added to with dangerous substances.

Because it is impossible to say how pure heroin is, it is easy for the user to overdose. Overdosing on heroin can cause heart failure, unconsciousness and coma. There is also a risk of the user choking on their own vomit if they are sick whilst unconscious.

Injecting heroin presents another set of risks. Sharing needles increases the risk of contracting serious diseases such as hepatitis and HIV. Long-term injecting may cause collapsed veins, appetite loss and severe constipation.

Heroin is probably the most addictive drug available in this country. Users become so dependent on it that they will do almost anything to fund their addiction. This is why heroin use is often associated with anti-social and criminal behaviour, such as child neglect and burglary.

Benefits of illegal drugs

Illegal drugs that have proven medical benefits are categorised as prescription-only medicines. This means that a doctor is able to prescribe them in certain situations.

For instance, methadone is sometimes prescribed to heroin addicts as part of a recovery programme. The prescription-only medicines (human use) order, which gives details of prescription-only drugs, can be bought from Her Majesty’s Stationery Office.

Other illegal drugs may have some beneficial medical effects. For example, some people believe that cannabis has pain relief properties. Studies have been undertaken to find out if cannabis can help with pain relief for people with conditions such as multiple sclerosis but, as yet, there is no conclusive evidence to suggest that cannabis is any more effective in controlling pain than other prescription drugs.

Some people also believe that cannabis may be effective as a relaxant in the treatment of conditions such as anxiety and epilepsy. However, again there is currently no conclusive evidence to support this.

Getting help

The first step is to admit that you have a problem

The first and most difficult step for people who misuse drugs is to recognise that they have a problem, and then to admit that they need help to deal with it.

Some people will realise that they have a problem, but find it hard to stop taking the drug even though they are aware of the consequences.

Others, may need someone else to help them realise that they have a problem, and that they need to get help to overcome it.

Signs of drug misuse

Signs of drug misuse, or addiction, may include:

  • continually increasing the dose of drugs to achieve the same effect,
  • a feeling of dependency on drugs, or a fear of stopping using drugs,
  • withdrawal symptoms if you stop taking the drug for a short time,
  • sudden mood changes,
  • a negative or changed outlook on life,
  • loss of motivation,
  • poor performance at work or at school,
  • problems with personal relationships,
  • borrowing or stealing money from friends and family, and
  • being secretive about activities and actions.

Once you recognise that have a drug problem, you should see your GP. They can give you advice, support and refer you for specialist treatment. Be open with your GP about your drug use, and your reasons for wanting to give it up. You may also want to tell close family and friends about your decision, and ask them for their support.

Getting help in an emergency

If a drug user is showing unusual symptoms or seems to be in distress, they may have had an allergic reaction to the drug they have taken, or they may have overdosed. Symptoms to look out for could include:

  • dizziness,
  • sickness or nausea,
  • sudden tiredness,
  • headaches,
  • muscle cramps and aches,
  • irregular breathing,
  • heavy slurring of speech,
  • convulsions, and
  • paralysis.

If you think someone is having a reaction or has overdosed, it is important to take the following actions immediately:

  • In a club or pub, get help from the staff straight away. Be completely honest about the drugs that have or may have been taken. Most clubs and pubs will have a member of staff who is first aid trained. This person should stay with the person until medical help arrives.
  • Phone 999. Tell the operator that you need an ambulance. Be clear and calm. Tell the operator exactly where the person is, what drugs they have taken and what symptoms they are showing. Be prepared to listen carefully to any advice given by the operator. You may be required to give mouth-to-mouth resuscitation, put the person into the recovery position or provide other life-saving treatment in an emergency situation. You will need to stay calm and keep a clear head.
  • Make sure the person’s airways are not obstructed. Look out for vomit blocking the airway and check that the person has not swallowed their tongue. Collect evidence of any drugs that have been taken. This will be vital for doctors to make a quick diagnosis and provide the best possible treatment.
  • Collect containers that drugs have been kept in, including wrappers, packets, cling film, tin foil and syringes. If the person has been sick, try to collect a small sample of vomit for analysis at the hospital.


Recovery from drug addiction can be a long process, starting with physical detoxification. This is coming off and staying off the drug, and learning to cope with withdrawal symptoms.

Recovery usually combines a range of treatments including psychological and behavioural therapy, as well as medication if required.

Treatment will vary depending on the specific addiction, particularly as some drugs are highly physically addictive, while others tend to lead more to psychological dependency.

If you are recovering from a drug addiction or if you stop taking drugs, it is common to experience withdrawal symptoms. These could include:

  • nausea or sickness,
  • aching muscles,
  • fever,
  • mood swings,
  • irritability,
  • anger or guilt,
  • depression, and
  • anxiety.

If you stop taking drugs, it is important to take one day at a time. Take advantage of the support open to you from medical professionals, and friends and family.

Make sure you stay away from situations where drugs will be available, by avoiding friends that take drugs, or places where you know you can get them.

If someone you know has recently stopped taking drugs, make sure you give them your full support. Help them find the right treatment options, and take some time to learn a about drug misuse so you can appreciate what they are going through.

This article was originally published by NHS Choices.