Phencyclidine (also called PCP or Angel dust) is a dissociative/anaesthetic developed in the 1960s by Parke & Davis pharmaceutical company.

PCP was used for several years in human anaesthesia, but patients became confused or delirious and experienced hallucinations afterwards. These effects, and its long half-life in the human body, made it unsuitable for medical applications. It is retained in fatty tissue and is broken down by human metabolism into PCHP, PPC and PCAA. When smoked, some of it is broken down by heat into 1-phenyl-1-cyclohexene (PC) and piperidine.

From the 1950s, PCP has been used medically only in veterinary medicine, mainly for horses, under the trade name of Sernylan. It was also placed in Schedule III of the Controlled Substances Act (CSA). In 1978 it was transferred to Schedule II of the CSA, and commercial manufacture was discontinued.

PCP is sometimes consumed recreationally, mainly in the United States. The limited demand is met by illegal production. The drug is sold in an extremely limited number of cities. It is available as a liquid (PCP base dissolved most often in ether), but typically it is sprayed onto leafy material such as marijuana, mint, oregano, or parsley, and smoked.

In its pure form, PCP is a white crystalline powder that readily dissolves in water. However, most PCP on the illicit market contains a number of contaminants as a result of makeshift manufacturing, causing the color to range from tan to brown, and the consistency to range from powder to a gummy mass. The drug is mentioned far more than it is actually encountered, being one of the rarest scheduled substances (second to extracted purified mescaline).

Whether PCP has any strong and consistent effects which are markedly different from other similar compounds is controversial. Some think that the drug's effects are as varied as its appearance. It may be that a moderate amount of PCP will cause users to feel detached, distant, and estranged from their surroundings. Numbness, slurred speech, and loss of coordination may be accompanied by a sense of strength and invulnerability. A blank stare, rapid and involuntary eye movements, and an exaggerated gait are alleged to be among the more observable effects.

Auditory hallucinations, image distortion, severe mood disorders, and amnesia may also occur. In some users, PCP may cause acute anxiety and a feeling of impending doom; in others, paranoia and violent hostility; and in some, it may produce a psychosis indistinguishable from schizophrenia. Many believe PCP to be one of the most dangerous drugs of abuse. Modification of the manufacturing process may yield chemically related analogues capable of producing psychotic effects similar to PCP.

PCP production is centered in the greater Los Angeles metropolitan area. Los Angeles-based street gangs, primarily the Crips, continue to distribute PCP to many cities in the United States using their cocaine trafficking operations. These gangs pose a particular problem due to their propensity for violence. During the late 1980s and early 1990s, the widespread availability and use of crack cocaine displaced demand for PCP. More recently, however, reporting suggests that PCP abuse is increasing slightly in many cities, as some crack addicts return to the use of this drug. For instance, the DEA Portland District Office reports a resurgence in the popularity of liquid PCP, also known as "sherm", among Portland area gangs. California street gangs reportedly are responsible for the reemergence of PCP in the Pacific Northwest. Treated cigarettes, which have a yellow tint caused by the liquid PCP, were first observed on the street in 1996, costing between $15 and $20 each. The DEA Philadelphia Field Division also reports that PCP was available readily in the region in 1998. The DEA seized three clandestine PCP laboratories in 2004.

More so than any other illegal substance, PCP has developed an elaborate mythological history surrounding itself, spread by such reputable sources as D.A.R.E. PCP is said in this urban legend to cause such entirely realistic hallucinations, such as that of spiders on the users' faces, which in turn causes them to create deep lacerations in the attempt at removing them.

Another famous mention is in the movie Terminator, where Arnold Schwarzenegger's violent attacks, including punching through a glass window without feeling it, are attributed to PCP by the police. Dissasociative anesthetics like PCP however are noted for closed eye hallucinations, not fully realistic ones. They are also noted for being depressives, inhibiting movement, not encouraging aggression.

Signs of PCP Abuse:

* Unpredictable behavior; mood may swing from passiveness to violence for no apparent reason.
* Symptoms of intoxication.
* Disorientation; agitation and violence if exposed to excessive sensory stimulation.
* Fear, terror.
* Rigid muscles.
* Strange gait.
* Deadened sensory perception (may experience severe injuries while appearing not to notice).
* Pupils may appear dilated.
* Mask like facial appearance.
* Floating pupils, appear to follow a moving object.
* Comatose (unresponsive) if large amount consumed. Eyes may be open or closed.

Note: PCP has stimulant, depressant, hallucinogenic and analgesic effects. Which of these will be most pronounced is unpredictable and depends on users personality, psychological state and the setting at time of use.