Psychoactive drug

These drugs may be used recreationally to purposefully alter one's consciousness (such as coffee, alcohol or cannabis), as entheogens for spiritual purposes (such as the mescaline-containing peyote cactus or psilocybin-containing mushrooms), and also as medication (such as the use of narcotics in controlling pain, stimulants to treat narcolepsy and attention disorders, as well as anti-depressants and anti-psychotics for treating neurological and psychiatric illnesses).

Many of these substances (especially the stimulants and depressants) can be habit-forming, causing chemical dependency and may lead to substance abuse.

Conversely, others (namely the psychedelics) can, in certain circumstances, help to treat and even cure such addictions.