Phencyclidine and Related Disorders
Phencyclidine and Related Disorders
Phencyclidine (PCP) is a street drug known as “angel dust”that causes physiological changes to the nervous and circulatory system, disturbances in thinking and behavior, and can cause hallucinations , psychotic disorder, mood disorder, and anxiety disorder.
PCP is the best known of several related drugs including ketamine, cyclohexamine, and dizocilpine. PCP was first synthesized by a pharmaceutical company in the 1950s and sold under the brand names Sernyl and Sernylan until 1967. It was hoped that PCP could be used as a dissociative anesthetic, because it produced a catatonic state where patients were dissociated from their environment and from pain, but not unconscious. Problems with side effects as the drug wore off, including agitated behavior and hallucinations, made PCP unsuitable for medical use. Ketamine (Ketlar, Ketaject) is less potent, has fewer side effects, and is approved for use as a human anesthetic.
PCP became an illicit street drug in the mid-1960s. It was most commonly found in large cities such as New York and San Francisco, and even today, most users tend to live in urban areas. Into the 1970s, PCP
appeared mainly as a contaminant of other illicit drugs, especially marijuana and cocaine . This complicated diagnosis of PCP use, as many people did not know that they had ingested the drug.
PCP is easy to manufacture and is inexpensive. By the late 1970s, in some urban areas its use equaled that of crack cocaine. Use of PCP peaked between 1973 and 1979. Since 1980, PCP use has declined, although as with most illicit drugs, its popularity increases and decreases in cycles. In 2005, 2.4% of high school seniors reported having used PCP at least once, and 1.3% of high school seniors had used it once in the past year.
People who use PCP exhibit both behavioral and physiological signs. The effects of PCP are erratic, and serious complications can occur at relatively low doses. It is often difficult to distinguish PCP use from the use of other illicit drugs, and many people who use PCP also abuse other substances. According to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (DSM-IV-TR), which presents guidelines used by the American Psychiatric Association for diagnosis of mental disorders, phencyclidine can induce mood disorder, psychotic disorder, and anxiety disorder—but these classifications are somewhat controversial and not all are recognized by international psychiatric organizations. Animal studies suggest that both conditions occur, just as they do with many other abused drugs.
PCP is a Schedule II drug under the Controlled Substances Act, which means it has a high potential for abuse and dependence and has severe restrictions for medical use. In its pure form, it is a white powder that dissolves easily in water. Once dissolved, the solution can be sprayed on tobacco or marijuana cigarettes. Less pure forms range from yellowish-tan to brown and can be a sticky mass. On the street PCP has many names including angel dust, devil dust, tranq, hog, crazy Eddie, rocket fuel, embalming fluid, wack, and ozone. Ketamine, which is legal and not regulated as a Schedule III controlled substance (which is has a lower potential for abuse than Schedule I or II drugs), also used illicitly, is known on the street as K, special K, and cat valium. Crack cocaine combined with PCP is sometimes called tragic magic. Marijuana laced with PCP is called love boat, killer weed, or crystal supergrass.
PCP is easy to manufacture and is inexpensively available on the street in most cities, especially East Coast cities. It can be eaten, smoked, injected, or snorted, and is readily soluble and will cross the skin barrier if liquid PCP is spilled on skin or clothing. The most common methods of ingestion are eating and smoking marijuana or tobacco on which liquid PCP has been sprayed. PCP is long-acting. It accumulates in body fat, and flashbacks can occur as it is released from fat during exercise.
PCP binds to receptors in the brain and interferes with the chemical reactions that mediate the transmission of nerve impulses. It is deactivated slowly by the liver and excreted in urine. Although there are no controlled human studies on PCP intoxication, monkeys allowed free use of PCP will dose themselves repeatedly and maintain an almost continuous state of intoxication. They exhibit withdrawal symptoms if their supply of the drug is restricted. PCP is considered to be psychologically and possibly physically addictive in humans.
PCP produces both physiological and psychological symptoms. Effects of the drug are erratic and not always dose-dependent. Physical symptoms include:
- involuntary rapid movements of the eyes vertically or horizontally
- high blood pressure
- racing heartbeat
- dizziness and shakiness
- increased body temperature
- reduced response to pain
- slurred speech
- excessive sensitivity to sound
- lack of muscle coordination
- muscle rigidity or frozen posture
- breakdown of muscle and excretion of muscle proteins in urine
Psychiatric and social symptoms include:
- disordered thinking and confusion
- impaired judgment
- belligerence aggressiveness
- impulsiveness and unpredictability
- schizophrenic-like psychoses
- hallucinations of sight, sound, or touch
- memory impairment
- difficulty in social-emotional relationships
- chaotic lifestyle including difficulty functioning at work or school, legal and financial problems
PCP is known for its variability of symptoms, which change both from person to person and from exposure to exposure. In addition, symptoms come and go throughout a period of intoxication that can last from one to two hours for low-dose exposure to one to four days for high-dose exposure. Severity of symptoms is not always related to the size of the dose as measured by blood levels of the drug.
Three rough phases of intoxication have been established: behavioral toxicity, stuporous stage, and comatose stage. Many patients fluctuate between phases, and some present symptoms that do not fit neatly into any phase. In the behavioral toxicity stage, people tend to gaze blankly while their eyes dart horizontally or vertically. Muscle control is poor, and the person may make repetitive movements, grind the teeth, or grimace. Body temperature, heart rate, and respiration are mildly elevated. Vomiting and drooling may occur.
In the stuporous phase the eyes are wide open, and the person appears wide awake, but in a stupor. Seizures may occur if the person is stimulated. The eyes may dart in any direction while the gaze remains fixed. Body temperature is increased substantially. Heart and respiration rate are increased by about 25%. Muscles are rigid with twitching.
In the comatose stage, which may last from one to four days, the person is in a deep coma. The pupils are dilated and the eyes drift. Body temperature is elevated to the point of being life-threatening. The heart
rate is dangerously high, increasing to about twice the normal level and blood pressure is dangerously low. Breathing may stop for brief periods (apnea). There is no response to pain, and the person sweats heavily. Death is possible, although most deaths with PCP occur in earlier stages through accidents or suicide .
In a recent analysis of PCP admissions, researchers found that 49% of people admitted for a substance-use problem with PCP as the primary substance were African American; another 26% were Hispanic, and 19% were Caucasian. Admissions for PCP as the primary drug were less than 1% of overall admissions for substance-use problems. In addition, admissions for PCP use in the United States were more frequent in the West and Northeast than in the South or Midwest. The average age at admission was 28 years, and most PCP users were male. In terms of education, people admitted for PCP substance-use problems were more likely than people admitted for other drugs to have dropped out of high school and less likely to have full-time employment. However, they were less likely than people admitted for other substances to have an accompanying psychiatric problem.
Diagnosis of PCP abuse or dependence is often complicated by the fact that symptoms are variable. Most people who use PCP also use other drugs (74% of users in one survey used at least one other substance); and PCP can be a contaminant in other street drugs or can itself be contaminated with other chemicals. PCP use is also found among people with psychiatric disorders. In many ways, PCP mimics the symptoms of schizophrenia .
The American Psychiatric Association describes two classes of PCP disorders: PCP dependence and PCP abuse. In addition, it recognizes seven other PCP-induced psychiatric disorders.
PCP dependence can be difficult to pinpoint because, unlike many other drugs of abuse, PCP does not necessarily cause craving in everyone who uses it, although some people report it. In addition, although studies of specific populations have identified signs of tolerance or withdrawal, these symptoms have not been clearly categorized for PCP use. Generally, a person with PCP dependence will engage in PCP use several times a day and persist in using it, even when psychological problems (such as anxiety or rage) and/or medical problems (such as high blood pressure or seizures) arise. Aggression has been identified as a key problem for people dependent on PCP. People with psychiatric disorders are more likely to have bad side effects from PCP than those without psychiatric problems. Because PCP is readily stored in fat and released as fat stores are used, adverse effects of PCP dependence can continue for weeks after the drug is discontinued.
People who exhibit signs of PCP abuse may use the drug less often then those with dependence, but they also may experience interference with their ability to fulfill their responsibilities at school, work, or home. In addition, with the impaired judgment associated with PCP use, the person may engage in dangerous behaviors, such as driving a car, while under the drug’s influence. The person’s use of the drug may have triggered trouble in their personal relationships or with the law.
Phencyclidine-induced disorders include:
- PCP intoxication with or without perceptual disturbances
- PCP intoxication delirium
- PCP-induced psychotic disorder
- PCP-induced mood disorder
- PCP-induced anxiety disorder
- PCP-induced disorders not otherwise specified
PCP intoxication and delirium are diagnosed by a history of recent PCP use, behavioral changes and physical changes that are not accounted for by any other substance use, medical condition, or psychiatric condition. PCP is present in the blood and urine. With PCP intoxication, a patient may have hallucinations but be aware that these are caused by PCP use.
PCP delirium is diagnosed when a patient exhibits muddled thinking, hostility, bouts of hyperactivity and aggressiveness, and schizophrenic-like symptoms, as well as the more severe physical symptoms listed above. PCP delirium can last for hours or days.
It may be difficult initially to separate PCP intoxication or delirium from other mental disorders, as symptoms may mimic depression, schizophrenia, mood disorders, conduct disorder , and antisocial personality disorder . People with PCP intoxication also have physical and psychological symptoms similar to those that occur with the use of other illicit drugs, complicating diagnosis. A complete physical and psychological history helps rule out these other conditions.
People experiencing PCP intoxication or delirium often hurt themselves or others. They are generally kept in an environment where there is as little stimulation as possible. They are restrained only as much as is necessary to keep them from hurting themselves or others until the level of PCP in their bodies can be reduced. Antipsychotic medications may be used to calm patients in cases of PCP delirium.
There are no quick ways to rid the body of PCP. If the PCP has been eaten, stomach pumping or feeding activated charcoal may help keep the drug from being absorbed into the bloodstream. Physical symptoms such as high body temperature are treated as needed.
Most people recover from PCP intoxication or delirium without major medical complications. Many are habitual users who return to use almost immediately. There are no specific behavioral therapies to treat PCP use. Antidepressants are sometimes prescribed. Long-term residential treatment or intensive outpatient treatment along with urine monitoring offers some chance of success. Narcotics Anonymous, a self-help group, may be helpful for some patients.
Relapse and return to PCP use is common, even among people who have experienced severe medical and psychiatric complications from the drug. Because many users also abuse other drugs, their success in renouncing PCP is tied to their successful treatment for other addictions. Successful treatment takes persistence, patience, and a functional support system, all of which many users lack.
PCP intoxication and related disorders can be prevented by not using the drug.
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National Clearinghouse for Alcohol and Drug Information. P. O. Box 2345, Rockville, MD 20852. Telephone: (800) 729-6686. Web site: http://www.health.org
National Institute on Drug Abuse. 5600 Fishers Lane, Room 10 A-39, Rockville, MD 20857. Telephone: (888) 644-6432. Web site: http://niad.nih.gov
Drug and Alcohol Services Information System. “The DASIS Report: Characteristics of Primary Phencycli-dine (PCP) Admissions: 2001.” Available online at: http://oas.samhsa.gov/2k4/PCPtx/PCPtx.htm
National Institute on Drug Abuse. “NIDA InfoFacts: PCP (Phencylcidine).” Available online at: http://www.nida.nih.gov/Infofacts/PCP.html
Tish Davidson, A.M.
Emily Jane Willingham, PhD