PCP is technically classified as a hallucinogen, but it belongs to a specific subcategory called dissociative drugs, which work very differently from classic hallucinogens like LSD or psilocybin. The National Institute on Drug Abuse divides hallucinogens into two broad categories: classic hallucinogens and dissociative drugs. PCP falls squarely into the dissociative camp, alongside ketamine and DXM. This distinction matters because the effects, the risks, and the way PCP acts on the brain are fundamentally different from what most people picture when they hear the word “hallucinogen.”
Why PCP Is Called a Dissociative, Not a Classic Hallucinogen
Classic hallucinogens like LSD and psilocybin work primarily on serotonin circuits in the brain. They intensify sensory experiences, produce vivid visual distortions, and can make colors appear brighter or sounds sharper. Some users report “hearing” colors or “seeing” sounds. The experience is rooted in altered perception of things that are actually there, plus occasional full hallucinations.
PCP works through an entirely different mechanism. It blocks a type of receptor in the brain called NMDA receptors, which are part of the glutamate signaling system. Glutamate is the brain’s primary excitatory chemical messenger, involved in learning, memory, and perception. When PCP blocks these receptors, the downstream effect is a cascade of disrupted signaling: reduced inhibition in certain brain circuits, excess release of both glutamate and dopamine (particularly in the prefrontal cortex), and a state that researchers have noted closely mimics the symptoms of schizophrenia.
The subjective experience reflects this different mechanism. Where LSD distorts what you see and feel, PCP disconnects you from your body and surroundings entirely. Users report feeling detached from reality, floating, or completely out of control. It can produce visual and auditory distortions, but the dominant effect is dissociation rather than the sensory fireworks associated with classic psychedelics.
What PCP Actually Feels Like
PCP was originally developed as an anesthetic, marketed under the name Sernyl for surgical use. It was pulled from human medicine because patients waking up from anesthesia experienced severe agitation, confusion, hallucinations, and delusional thinking. Those same properties define the recreational experience.
At lower doses, PCP produces numbness, a sense of detachment, and mild euphoria. Users may feel invulnerable or disconnected from pain. At higher doses, the effects become far more intense and unpredictable: severe confusion, delusions, extreme agitation, and full-blown psychotic episodes with hallucinations. Unlike the relatively predictable arc of an LSD experience, PCP can swing rapidly between sedation and violent agitation in the same episode.
Physical Effects That Set PCP Apart
One of the clearest differences between PCP and classic hallucinogens is the range of serious physical effects PCP produces. Classic hallucinogens like LSD have relatively mild physical side effects, primarily elevated heart rate and dilated pupils. PCP affects the body in ways that can be dangerous on their own, independent of any behavioral risks.
The most distinctive physical sign of PCP use is nystagmus, an involuntary jerking movement of the eyes. This occurs in 60 to 90 percent of PCP toxicity cases and can be horizontal, vertical, or rotary. Unusually, PCP-intoxicated individuals may display this eye movement while fully awake and agitated, unlike most other drugs that cause it only during sedation.
High blood pressure appears in roughly 60 percent of toxicity cases, and rapid heart rate in about 30 percent. Muscle rigidity is common and can progress to severe involuntary movements including facial grimacing, neck twisting, and full-body stiffness. This intense muscle activity generates dangerous levels of heat in the body and can cause rhabdomyolysis, a breakdown of muscle tissue that releases proteins into the bloodstream and can damage the kidneys. Elevated markers of muscle breakdown show up in about 70 percent of PCP toxicity cases.
PCP and Violence: What Research Shows
PCP has a reputation as a drug that makes people violent and superhuman. The reality is more complicated. Research suggests that PCP-induced aggression may be less common than the public perceives, and that violent behavior during PCP use often relates to individual personality traits, environmental factors, or the effects of other substances used at the same time.
That said, the association isn’t entirely a myth. In one study of 287 participants, PCP users were significantly more likely to have engaged in violence during the prior year compared to people with cannabis use disorder or combined alcohol and cannabis problems. About 39 percent of the sample endorsed general aggression and 30 percent reported intimate partner violence. But these rates were actually lower than estimates from broader substance treatment studies, where between one-third and one-half of all participants with substance dependence reported perpetrating partner violence. PCP does carry a real risk of aggressive behavior, but the “PCP berserker” stereotype overstates how often it happens.
How PCP Mimics Schizophrenia
One of the most striking things about PCP is how closely its effects mirror the symptoms of schizophrenia. This isn’t coincidental. The leading theory is that PCP’s blockade of NMDA receptors reduces the activity of inhibitory neurons in the brain, which leads to an uncontrolled flood of glutamate and dopamine in the prefrontal cortex. This is essentially the same neurochemical pattern seen in schizophrenia, and it produces a similar constellation of symptoms: paranoid delusions, auditory hallucinations, disorganized thinking, emotional flatness, and social withdrawal.
This connection is so robust that researchers have used PCP and related drugs as models for studying schizophrenia in laboratory settings. The psychotic episodes PCP triggers can last hours to days, and in some cases, repeated use has been associated with prolonged psychotic states that persist even after the drug has cleared the body.
PCP Compared to Other Dissociatives
PCP belongs to the same drug family as ketamine and DXM (the cough suppressant found in some over-the-counter medications). All three block NMDA receptors, but PCP is the most potent and longest-lasting of the group. Ketamine at high doses can produce a state of near-complete sensory detachment that users call a “K-hole,” which shares some features with a bad PCP experience. But ketamine’s effects are shorter and generally more predictable.
PCP is also far more likely to produce severe physical complications. The combination of extreme agitation, muscle rigidity, dangerously high body temperature, and the potential for seizures makes PCP toxicity a qualitatively different medical situation than an adverse reaction to LSD or even ketamine. Non-traumatic deaths from PCP have been linked to cardiac arrest, brain hemorrhage from severe high blood pressure, and kidney failure from muscle breakdown.
Legal Status
PCP is classified as a Schedule II controlled substance under the federal Controlled Substances Act. This means the government recognizes it has a high potential for abuse but also acknowledges a limited accepted medical use (it is no longer used in practice on humans, though it technically retains this classification). Possession, manufacture, and distribution carry severe federal and state penalties.