PCP
Potent dissociative anesthetic and NMDA antagonist originally developed for medical use, now known primarily for recreational misuse and severe psychological effects.
PCP was originally developed in the 1950s as a surgical anesthetic but was discontinued for human medical use due to severe adverse psychological effects including agitation, hallucinations, and psychosis. Pharmacologically, it is one of the most potent NMDA antagonists among dissociative drugs, with a notably long half-life that contributes to prolonged and unpredictable effects. Research on PCP has been instrumental in the NMDA receptor hypofunction hypothesis of schizophrenia. Evidence for harm is robust, with well-documented cases of acute psychosis, violent behavior, and neurotoxicity at recreational doses. There are no established therapeutic applications in current clinical practice.