Psychedelics are a class of drug whose primary action is to trigger psychedelic experiences via serotonin receptor agonism, causing thought and visual/auditory changes, and altered state of consciousness. Major psychedelic drugs include mescaline, LSD, psilocybin and DMT. Studies show that psychedelics are physiologically safe and do not lead to addiction. Studies conducted using psilocybin in a psychotheraputic setting reveal that psychedelic drugs may assist with treating depression and alcohol addiction, possibly also nicotine addiction.
Differing with other psychoactive drugs, such as stimulants and opioids, psychedelics tend to qualitatively alter ordinary conscious experience. Whereas stimulants cause energized feelings and opioids produce a relaxed euphoric state, the psychedelic experience is often compared to non-ordinary forms of consciousness such as trance, meditation, yoga, religious ecstasy, dreaming and even near-death experiences. Most psychedelic drugs fall into one of the three families of chemical compounds: tryptamines, phenethylamines, or lysergamides. Although lysergamides are their own group, they are in fact both a tryptamine and a phenethylamine