Citation

Vale A. Medicine (Abingdon) 2003; 31(9): 23-25.

Copyright

(Copyright © 2003, Medicine Publishing)

DOI

10.1383/medc.31.9.23.27714

PMID

unavailable

Abstract

Many substances, some obtained from natural sources, are taken to alter the mental state of the user. These include amfetamines, cannabis, cocaine, Ecstasy, ethanol, lysergic acid diethylamide, mushrooms, opioid analgesics and volatile substances. Such substances can be classified according to whether their major effect is to alter perception, or to stimulate or depress the CNS, though there is some overlap between groups. Substances that predominantly depress the CNS (e.g. ethanol) may, for example, arouse and disinhibit behaviour before exerting their principal action. Other drugs that initially stimulate the brain may impair consciousness if taken in sufficient quantities.