How drugs affect your body

Different types of drugs affect your body in different ways, and the effects associated with drugs can vary from person to person. How a drug effects an individual is dependent on a variety of factors including body size, general health, the amount and strength of the drug, and whether any other drugs are in the system at the same time. It is important to remember that illegal drugs are not controlled substances, and therefore the quality and strength may differ from one batch to another.

Drugs can have short-term and long-term effects. These effects can be physical and psychological, and can include dependency.

You may act differently, feel differently and think differently if you have taken drugs. And you may struggle to control your actions and thoughts.

You might begin to use drugs without thinking about any harm to your body. You might think drugs won't become a problem because you are only a casual user. The more you take a drug, the more likely you are to build up a tolerance to its effects. This can lead to the need to take larger doses to obtain the effects of the drug. For this reason, evidence suggests that after prolonged use, many drugs can cause dependence. Drug dependence can quickly begin to affect your psychological and physical health, and can also affect your work and social life.

It is important to remember that there is no safe level of drug use.

Different drugs, different effects

Drugs affect your body's central nervous system. They affect how you think, feel and behave. The three main types are depressants, hallucinogens and stimulants:
  • Depressants slow or 'depress' the function of the central nervous system. They slow the messages going to and from your brain. In small quantities depressants can cause a person to feel relaxed and less inhibited. In large amounts they may cause vomiting, unconsciousness and death. Depressants affect your concentration and coordination, and slow your ability to respond to situations. It is important to not operate heavy machinery while taking depressants. Alcohol, cannabis, GHB, opiates (heroin, morphine, codeine) and benzodiazepines (minor tranquillisers) are examples of depressants.
  • Hallucinogens distort your sense of reality. You may see or hear things that are not really there, or see things in a distorted way. Other effects can include emotional and psychological euphoria, jaw clenching, panic, paranoia, gastric upset and nausea. Ketamine, LSD, PCP, 'magic mushrooms' and cannabis are examples of hallucinogens.
  • Stimulants speed or 'stimulate' the central nervous system. They speed up messaging to and from the brain, making you feel more alert and confident. This can cause increased heart rate, blood pressure and body temperature, reduced appetite, agitation and sleeplessness. In large amounts stimulants may cause anxiety, panic, seizures, stomach cramps and paranoia. Caffeine, nicotine, amphetamines (speed and Ice), cocaine and ecstasy (MDMA) are examples of stimulants.

Risk factors for drug-related harm

The effects of a drug, and how long they last, depend on a number of factors:
  • the type and strength of drugs that you use
  • how the drug was made -- substances manufactured in home labs may contain bacteria, dangerous chemicals and other unsafe substances, and have an unknown strength. Even one dose may cause an overdose that leads to brain damage or death
  • your physical characteristics (including height, weight, age, body fat and metabolism)
  • the dose that you take
  • how often and for how long you have been using drugs
  • how you ingest the drug (by inhalation, by injection or orally). Compared with swallowing a drug, inhalation and injection are more likely to lead to overdose and dependence. If you are injecting drugs, sharing injecting equipment will increase your risk of contracting serious diseases such as hepatitis and HIV. It will also increase your risk of serious infection
  • your mental health, mood and environment (that is, whether you are in a secure, happy place or an unsafe place) can affect the experience you have when taking drugs. If you have a mental health condition, drugs may exacerbate or complicate the symptoms of that condition
  • whether you mix drugs, including alcohol. In particular, alcohol use may lead to high risk behaviour (such as drink driving) which can result in the serious injury or death of yourself or others.

Physical harms from drug use

Drug use can affect short- and long-term health outcomes. Some of these health outcomes can be serious, and possibly irreversible.

Drug use can lead to risky or out of character behaviour. When affected by drugs:

  • You are more likely to have an accident (at home, in a car, or wherever you are).
  • You may be vulnerable to sexual assault or you may engage in unprotected sex. Either of these could lead to pregnancy and sexually transmitted infection.
  • You could commit a sexual assault or other violent act.
  • You may find it hard to sleep, think, reason, remember and solve problems.
Drug use can also result in long-term health outcomes that include:
  • harm to organs and systems in your body, such as your throat, stomach, lungs, liver, pancreas, heart, brain, nervous system
  • cancer (such as lung cancer from inhaling drugs)
  • infectious disease, from shared injecting equipment and increased incidence of risk-taking behaviors
  • harm to your baby, if you are pregnant
  • acne, or skin lesions if the drug you are taking causes you to pick or scratch at your skin
  • needle marks and collapsed veins, if you inject regularly
  • baldness
  • male pattern hair growth in women, such as facial hair
  • jaw and teeth issues due to clenching and grinding your teeth; or bad breath, teeth cavities and gum disease
  • mood swings and erratic behavior
  • addiction
  • psychosis (losing touch with reality)
  • accidental overdose
  • higher risk of mental illness, depression, suicide and death.