Phencyclidine (PCP) is a dissociative hallucinogenic drug that results in an alteration of an individual’s perception of reality, such that they can experience significant psychosis (hallucinations and delusions) and dissociation (feeling as if one is not real, as if they are leaving their body, or as if one’s surroundings are not real).

PCP was initially used as an anesthetic; however, the drug resulted in significant psychotic symptoms in individuals who were administered it, and it is no longer commonly used for that purpose. It is classified as a Schedule II controlled substance by the DEA.
 

The Effects of PCP

PCP affects numerous neurotransmitters, including the excitatory neurotransmitter NDMA, acetylcholine, dopamine, and enkephalins and endorphins. According to the National Institute on Drug Abuse (NIDA): 
  • When taken at low doses, PCP produces effects similar to alcohol, such as slurred speech, euphoria, giddiness, bloodshot eyes, and issues with balance and walking. Individuals may also become aggressive and experience hallucinations. 
  • At moderate doses, PCP induces sedation as well as confusion. 
  • At high doses, PCP is likely to produce catatonic states, comatose states, and even seizures. 
Research studies have demonstrated that PCP use can result in significant damage to the brain that can lead to serious cognitive and psychiatric/psychological issues.

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    • Damage to the frontal cortex of the brain: Significant damage to the frontal areas of the brain has been demonstrated to occur as a result of PCP use and abuse. This results in significant issues with attention (especially maintaining attention and shifting attention), impulse control, emotional control, and problem-solving. Individuals with frontal brain damage are often impulsive, have violent outbursts or other emotional issues, and have issues working out even simple problems.
    • Significant issues with memory: PCP inhibits the function of the neurotransmitter acetylcholine, which is important in memory. This may result in individuals with moderate to long-term histories of PCP abuse developing significant memory problems. Acetylcholine is involved in the consolidation and transfer of new information into long-term storage. Individuals who suffer brain damage as a result of PCP use may have significant difficulty retaining new material and remembering it.
    • Damage to the cerebellum: Research has also demonstrated that individuals who have abused PCP for a significant length of time demonstrate dysfunction in the cerebellum, a complex structure at the posterior portion of the brain. The cerebellum has numerous connections throughout other areas of the brain, but particularly to the frontal cortex. Cerebellum damage can result in issues with memory and movement, and changes in life-sustaining functions, such as heart rate, breathing rate, and blood pressure.
    • Depression or psychosis: Chronic use of PCP results in a massive release of neurotransmitters in the brain and, later, a massive depletion of neurotransmitters in the brain once the drug is discontinued. This can result in an increased likelihood to develop seizures or issues with emotional functioning, including depression and psychosis, even after one stops using PCP.
    • Issues with judgment: Even at low levels, use of PCP can result in significant issues with judgment that can make an individual more prone to accidents or the effects of poor decision-making that can result in serious consequences. Individuals often lack emotional control and are very impulsive under the influence of PCP, and they can potentially experience hallucinations and delusions. This can result in extremely dangerous situations. People who mix PCP with other drugs, such as alcohol, stimulants, cannabis products, etc., are even more prone to impulsivity, being accident-prone, and poor decision-making.

Overdose: When individuals use PCP, they often become impulsive and are unable to monitor their own behavior. This can lead to potential issues with overdose. Of course, individuals who use PCP in conjunction with other drugs of abuse are more likely to overdose on one or more drugs due to issues with judgment and decision-making.

Potential overdose effects as a result of PCP abuse can be serious. Overdose can result in uncontrollable body movements, hallucinations, delusions, significant agitation, significant aggression, catatonic-like states, comatose states, and life-threatening seizures. PCP overdose typically presents as the person being comatose or catatonic, or as extremely agitated, delirious, and psychotic. Both situations are potentially fatal situations.

There is no specific medication that can treat the symptoms of a PCP overdose. Medical personnel can only attempt to stabilize the individual, treat the specific symptoms, and administer IV fluids. If the individual is psychotic and aggressive, antipsychotic medications may work. If the individual is catatonic or comatose, CPR and other life-sustaining techniques may be appropriate.