Module 6: how drugs work: facilitator's guide

3.1 Classifying drugs by their effect on the central nervous system

Page last updated: 2004

Drugs can be classified in many ways including:

  • uses (medicinal or recreational)
  • effect on the body (i.e. CNS)
  • source (synthetic or plant)
  • legal status (legal/illegal)
  • risk status (dangerous/safe)
One of the most common and useful ways of classifying a drug is by the effect that it has on a person's central nervous system (CNS).

The brain is the major part of the CNS, and this is where psycho-active drugs have their main effect.

Overhead transparency

Classifying drugs by their effect on CNS

  • Stimulants - speed up the activity of a CNS which often results in the user feeling more alert and more energetic (e.g. amphetamines, cocaine).

  • Depressants - slow down the activity of the CNS, which often results in the user feeling less pain, more relaxed and sleepy (e.g. alcohol, major tranquillisers).

  • Hallucinogens - have the ability to alter a user's sensory perceptions by distorting the messages carried in the CNS (e.g. LSD and kava).

  • Others - include psycho-active drugs that do not fit neatly into one of the other categories (e.g. anti-depressants such as Zoloft and mood stabilisers such as Lithium)