Drug Information

May 5, 2016

About drugs

This drug information section has been designed to help identify various drugs, provide information about those drugs, and assist in addressing drug-related issues.

The Drug Foundation's message is clear: no drug use is the safest drug use. We also acknowledge there will always be occasions  when legal and illicit drugs are used - regardless of risks and warnings. It is therefore in our interest to provide factual health and safety information to help keep New Zealand's communities safe.


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What is a drug?

A drug is a substance, solid, liquid or gas, which changes the functions or structures of the body in some way. This excludes food and water, which are required to maintain normal body functioning.

The drugs of most concern to the community are those that affect a person's central nervous system (CNS). They act on the brain and can change the way a person thinks, feels or behaves. These are psychoactive drugs.

A range of drug-related harms could result from inappropriate use of substances, including negative health effects, family and social problems, psychological and emotional difficulties, legal and economic problems, and possibly death. It is important to remember that many people start and continue to use drugs to find relief and escape from problems.

Furthermore people use drugs to change how they feel because they want to feel better or different. They use drugs for the perceived benefits, or the benefits experienced, not for the potential harm.

There is a prevailing community fear that if a person uses drugs, they will become dependent or 'addicted'. No drug leads to an immediate physical or psychological dependence. However drug-related harm can happen at all levels of use, from initial use to dependent use.

Physical dependence may occur when a person's body adapts to and becomes used to functioning with the drug present.

Psychological dependence may occur when a person finds that using a drug becomes more important than other activities in their life and/or they feel that they have to use it to perform certain activities.

Classifying drugs

The two most common ways of classifying drugs are:

  • according to the legal status of the drug; and
  • according to the drugs effects on the CNS.

Legal status - Most 'legal' drugs are subject to restrictions and controls that affect their availability, quality and price. With illegal or illicit drugs, there are no quality or price controls. This means that a user can never be sure of the drug's strength, purity or toxicity. Also various batches of an illegally manufactured drug may have different mixtures of the drug and other additives, for example talcum powder, sugar, caffeine, or, in some cases, household cleaning powders and poisons.

Drug effects

There are three main types of drugs, classified by their effects on the central nervous system. These are depressants, hallucinogens and stimulants.


Depressant drugs slow down the functions of the central nervous system. They don't necessarily make you feel depressed. Moderate amounts of depressants can make you feel relaxed. Some depressants cause euphoria and a sense of calm and wellbeing. they may be used to 'wind down' or to reduce anxiety, stress or inhibition. Because they slow you down, depressants affect coordination, concentration and judgement. This makes driving and operating machinery hazardous.

in larger quantities, depressants can cause unconsciousness by reducing breathing and heart rate. Death may result. Combining depressants increases their effects and increases the risk of overdosing.

Alcohol, cannabis, benzodiazepines, inhalants and opiates are examples of a depressant drug.


Hallucinogens, also known as 'psychedelic' drugs, change the way a person perceives or experiences the world. A person may see or hear things that do not exist. Hallucinogens can also affect a person's thinking, sense of time and emotions. Effects of hallucinogens can include panic, paranoia and loss of contact with reality. In extreme cases, this can result in dangerous behaviour, like walking into traffic or jumping off a roof. Driving while under the influence of hallucinogens is extremely hazardous. It is common for users to take minor tranquillisers/benzodiazepines or cannabis to help them reduce the effects of and hallucinogenic drug. 

LSD and ecstasy are examples of hallucinogens.


Stimulants speed up or stimulate the central nervous system and can make the user feel more awake, alert and confident. Stimulants also increase heart rate, body temperature and blood pressure. Other physical effects include reduced appetite, dilated pupils, talkativeness, agitation, and sleep disturbance. Large quantities of stimulants can cause anxiety, panic, seizures, headaches, stomach cramps, aggression and paranoia. Prolonged use or sustained use of stimulants can also cause these effects.

Cocaine, methamphetamine, speed, party pills, and caffeine are examples of stimulants.

Other considerations

Knowing what effects a drug has on the CNS does not predict exactly how a drug will affect any one person. Other considerations include:

  • How much of the drug is taken and how often: generally, the higher the quantity taken, the greater the effect. Overdose occurs when the amount of the drug taken exceeds the body's ability to cope with the drug.
  • How the drug is taken: generally, drugs that are injected or inhaled act very quickly and the effects are more intense. Snorting through the nose is the next fastest-acting method of administration, while the effects of drugs eaten or swallowed take longer to occur.
  • Physical characteristics of the user.
  • The mood and environment of the user: how a person is feeling can have a significant impact on drug effects. Users are more likely to enjoy the experience in a comfortable social atmosphere than in a threatening environment.
  • Tolerance to the substance: the first time a person uses a drug, they have a very low tolerance and are likely to feel the effects very strongly. Generally the more often a drug is used the less intense the effects will be. Users feel they need to take larger amounts to get the desired effect.
  • Polydrug use (using more than one drug): users often have a primary drug of choice, but will use more than one or more other drugs to increase or reduce the effects of the primary drug of choice or as a substitute. Combining drugs can increase or alter the usual effects, often in unpredictable ways.

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