Hallucinogen

This general group of pharmacological agents can be divided into three broad categories: psychedelics, dissociatives, and deliriants. These classes of psychoactive drugs have in common that they can cause subjective changes in perception, thought, emotion and consciousness. Unlike other psychoactive drugs, such as stimulants and opioids, these drugs do not merely amplify familiar states of mind, but rather induce experiences that are qualitatively different from those of ordinary consciousness. These experiences are often compared to non-ordinary forms of consciousness such as trance, meditation, and dreams.

Hollister's criteria for establishing that a drug is hallucinogenic is:

Not all drugs produce the same effect and even the same drug can produce different effects in the same individual on different occasions.

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