How could drugs affect you?

The effects of any drug vary from person to person. How a drug affects a person can depend on their size, weight and health, also whether the person is used to taking the drug, and whether other drugs are in their system at the same time.

The effects will also depend on the amount taken. It can be hard to judge how much of an illegal drug has been taken, as they are uncontrolled, so quality and strength will vary from one batch to another.



These include alcoholbenzodiazepines (minor tranquillisers), cannabisGHBheroin, morphine, codeinemethadone, and some inhalants.

Depressants do not necessarily make a person feel depressed. They affect the central nervous system, slowing down the messages between the brain and the body.

They can affect concentration and coordination. They slow down the person’s ability to respond to unexpected situations. In small doses they can cause a person to feel more relaxed and less inhibited. In larger doses they can cause drowsiness, vomiting, unconsciousness and death.


These include caffeine, ephedrine, nicotineamphetaminescocaine and ecstasy (MDMA).

Stimulant drugs speed up the messages between the brain and the body. The can make a person feel more awake, alert, confident or energetic.

Large doses of stimulants can cause over-stimulation, causing anxiety, panic, seizures, headaches, stomach cramps, aggression and paranoia. Long-term use of strong stimulants can also cause these effects.


These include ketamine, LSD, datura, magic mushrooms (psilobycin) and mescaline (peyote cactus)Cannabis and ecstasy can also have hallucinogenic qualities.

Hallucinogens distort a person’s perception of reality. People who have taken them may imagine they see or hear things, or what they see may be distorted. The effects of different hallucinogens vary.

There is no safe level of drug use. Use of any drug always carries some risk—even medications can produce unwanted side effects. It is important to be careful when taking any type of drug.

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Other effects of drug use

Pregnancy and breastfeeding

Many drugs can cross the placenta and affect the unborn child.

Drugs and driving

It is dangerous to drive after taking drugs. The effects of drugs can affect driving ability, increasing the chance of an accident.
Symptoms of withdrawal and ‘coming down’ after drug use can also affect driving ability.

Read more about the effects of drugs on safe driving.

Drugs and the workplace

Under occupational health and safety legislation, all employees have a responsibility to make sure they look after their own and their co-workers’ safety.

The effects of drugs, and the symptoms of coming down and withdrawal, can affect a person’s ability to work safely and effectively.

Tolerance and dependence

There is evidence that after prolonged use, many drugs can cause dependence. People who use a drug regularly can develop dependence and tolerance to it. This means they need to take larger amounts of the drug to get the same effect.

Dependence on a drug can be psychological, physical, or both. People who are dependent on the drug find that using the drug becomes far more important than other activities in their life. They crave the drug and find it very difficult to stop using it.

People who are psychologically dependent on a drug may find they feel the urge to use it when they are in specific surroundings, such as socialising with friends.

Physical dependence occurs when a person’s body adapts to a drug and gets used to functioning with the drug present.

Getting help

In Australia, there are many different treatment options for drug problems. Some aim to help a person stop using a drug, while others aim to reduce the risks and harm related to their drug use.


If a dependent person stops taking a drug, they may have withdrawal symptoms and cravings while their body gets used to functioning without the drug.

Note: Seek medical advice for withdrawal from alcohol or benzodiazepines, as it may cause seizures.

What to do if you are concerned about someone’s drug use

If you are concerned about someone’s drug use, there is help available. Contact the alcohol and drug information service in your state or territory.

What to do in a crisis

Always call triple zero (000) if a drug overdose is known or suspected and remember that paramedics are not obliged to involve the police. If someone overdoses or has an adverse reaction while using GHB, it is very important that they receive professional help as soon as possible. A quick response can save their life.