What is the medical use for LSD Mescaline and PCP?

The best definition of what is considered a classic or true psychedelic is the following -- “a psychedelic drug is one which, without causing physical addiction, craving, major physiological disturbances, delirium, disorientation, or amnesia, more or less reliably produces thought, mood, and perceptual changes otherwise rarely experienced except in dreams, contemplative and religious exaltation, flashes of vivid involuntary memory and acute psychoses”. Over the decades, the term has been contaminated to include far more substances than originally intended. Many pharmacologists define psychedelic drugs as chemicals which have an LSD or mescaline like action on certain serotonin receptors. This essentially means tryptamines and phenethylamines, as no psychedelics from other chemical families have been discovered, with the possible exception of piperazines. Many people have applied the term psychedelic to other drugs including cannabis, dissociative arylcyclohexylamines such as PCP and ketamine, tropane deliriants such as atropine, other psychoactives such as Amanita muscaria and Salvia divinorum. More properly, these should be grouped with psychedelics under the category of entheogens, a term which describes the way a drug is used rather than its pharmacological properties.