Drugs are substances like opioids, cannabinoids, and cocaine. The WHO Classification of Diseases uses the term psychoactive substances (ICD10 1992).
A drug, therefore is any substance when taken affects the central nervous system whether through stimulation, sedation or hallucinations.
There are many ways of classification of “drugs”, some use terms like White poisons, Heroin, Cocaine or Black poisons (Opium and Cannabis). Others classify drugs according to their effects on the CNS.

1. Narcotic analgesics: like Morphine, Codeine, Heroin, Hydromorphine and Methadone.
2. Sedatives / tranquilizers: Barbiturates, Benzodiazepines and Inhalants.
3. Stimulants: Cocaine, Amphetamines.
4. Hallucinogens: Ketamine, Magic Mushrooms.