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.
Phencyclidine (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 in which 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 illict 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.
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 ( 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
PCP is a Schedule II drug under the Controlled Substances Act. 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, 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.
Causes and symptoms
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, 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
- 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, stuperous 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 stuperous 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 the 1970s, PCP was used mainly by adolescents. Today the largest regular users are between the ages of 26 and 35. Men outnumber women users two to one, and men account for about three-quarters of PCP-related emergency room visits. Most users live in cities. About 90% of people who use PCP use other drugs as well, usually marijuana and alcohol. About 3% of substance abuse deaths are caused by PCP. Studies by the National Institute of Drug Abuse show that PCP use by high school students has declined steadily from about 13% in 1979 to about 4% in 1997.
Diagnosis of PCP abuse or dependence is often complicated by the fact that symptoms are variable. Most people who use PCP use other drugs; 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 recognizes two levels of PCP disorders: PCP dependence and PCP abuse. In addition, it recognizes seven other PCP-induced psychiatric disorders.
PCP dependence is characterized by a psychological dependence or craving for the drug, as well as withdrawal symptoms if it is discontinued. Although physical dependence has been shown in animal studies with suggestions that physical dependence is present in heavy human users, no human studies have confirmed this. Heavy users may take the drug several times a day. They continue to use it despite experiencing psychological or physical problems. People with psychiatric disorders are more likely to have bad side effects from PCP than those without psychiatric problems. Adverse effects of PCP dependence can continue for weeks after the drug is discontinued.
Individuals with PCP abuse use the drug less regularly than those with PCP dependence. They experience both physical and psychological symptoms of PCP intoxication and often are unable to meet the normal demands of society (work, school, family responsibilities). Because PCP use impairs judgment and increases aggressiveness, they often are involved in accidents while under the drug's influence.
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. Since 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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Galanter, Marc and Herbert D. Kleber, eds. Textbook of Substance Abuse Treatment. 2nd ed. Washington DC: American Psychiatric Press, Inc., 1999.
Giannini, James. Drug Abuse: A Family Guide to Detection, Treatment and Education. Los Angeles: Health Information Press, 1999.
Sadock, Benjamin J. and Virginia A. Sadock, eds. Comprehensive Textbook of Psychiatry. 7th ed. Vol.1. Philadelphia: Lippincott Williams and Wilkins, 2000.
National Clearinghouse for Alcohol and Drug Information. P. O. Box 2345, Rockville, MD 20852. (800) 729-6686. <http://www.health.org> .
National Institute on Drug Abuse. 5600 Fishers Lane, Room 10 A-39, Rockville, MD 20857. (888) 644-6432. <http://niad.nih.gov> .
Tish Davidson, A.M.