Page "Consciousness" Paragraph 61

A variety of psychoactive drugs have notable effects on consciousness.

These range from a simple dulling of awareness produced by sedatives, to increases in the intensity of sensory qualities produced by stimulants, cannabis, or most notably by the class of drugs known as psychedelics.

LSD, mescaline, psilocybin, and others in this group can produce major distortions of perception, including hallucinations ; some users even describe their drug-induced experiences as mystical or spiritual in quality.

The brain mechanisms underlying these effects are not well understood, but there is substantial evidence that alterations in the brain system that uses the chemical neurotransmitter serotonin play an essential role.