Phencyclidine (PCP)-Related Psychiatric Disorders Clinical Presentation
- Author: Alan D Schmetzer, MD; Chief Editor: Iqbal Ahmed, MBBS, FRCPsych(UK) more...
If a patient, or any family or friends who are present, can tell the physician reliably what substance has been used, it is obviously of help. Asking specifically about PCP can produce better information some of the time. However, because PCP is sold under other names, the historian may be honest as far as is known, but the history still may be inaccurate.
The Mental Status Examination is the most important area of abnormality in PCP intoxication. A great deal of variability occurs in the mental status findings with these patients. At times, their exams may appear normal or nearly so, when a few minutes later (perhaps 20 or so), obvious psychosis and possible evidence of dangerousness to self and/or others appear. Therefore, one must document the hallucinations, delusions, and mood-related issues (such as suicidal and homicidal thinking) that are present carefully and with reference to the time of the examination, as well as commenting on any changes noted during the examination.
PCP-intoxicated individuals frequently seem to feel a need to undress, whether due to their elevated temperature or for some delusion-related impulse. These patients may appear highly distressed, often crying and upset and citing their suicidal and homicidal urges as related to this discomfort. Affective lability is also noted, with a wide range moving from normal or near-normal mood to rage, dysphoria and depression, or anxiety.
Orientation and other mental status measures of mentation are also important to document because PCP produces a drug-induced delirium as well as the psychosis. Concentration is poor, so serial 7 calculations or spelling the word "world" backwards or forwards is usually difficult for such patients. Judgment is impaired with impulsivity being commonly observed, as well as a seeming lack of normal fear. Insight widely varies from moment to moment and cannot be relied upon to remain stable over any period of time.
The physical examination may be difficult because these patients usually are not very cooperative but, if possible, look for increased deep tendon reflexes and nystagmus (particularly vertical but horizontal or rotatory nystagmus are also seen). Other evidence of loss of muscle coordination may also be noted. Typical anticholinergic findings are common because PCP is a highly anticholinergic substance. Elevations in vital signs are also often present for this reason, with tests of blood pressure and pulse, as well as temperature, likely to yield abnormally high findings. Keep in mind that PCP is related to the anesthetics, and the findings will be similar to those observed as people descend into dose-related anesthesia.
Physical examination findings of PCP-intoxicated individuals vary in accordance with the serum level of the drug, as follows:
Lower blood levels (20-30 ng/mL) cause a picture of sedation, irritability, hyperactivity, impaired attention, and mood elevation.
As the level rises above 30 ng/mL, physical examination show progressive levels of ataxia, paresthesias, and psychosis.
At 100 ng/mL, stimulant effects are noted most, with hypertension and hyperreflexia becoming more pronounced.
At levels of more than 100 ng/mL, stupor and seizures can occur. In this range, overdose-related death is possible.
Risk factors for use of PCP include the following:
Male sex (72%)
African American (54%) or Hispanic ethnicity
Young adult age range (62% of people treated for PCP overdose are in the second decade of life)
Obviously to ingest PCP, one must have access to this illicit substance, but it is fairly inexpensive and simple to synthesize and is thus relatively easy to obtain.
Sometimes, people who are intoxicated on PCP do not know that it is the drug they have received. Rather, the buyer of the drug is often told that he or she is getting something more exotic, such as "THC" or a designer drug.
Allen RM, Young SJ. Phencyclidine-induced psychosis. Am J Psychiatry. 1978 Sep. 135(9):1081-4. [Medline].
Aniline O, Allen RE, Pitts FN Jr, Yago LS, Pitts AF. The urban epidemic of phencyclidine use: laboratory evidence from a public psychiatric hospital inpatient service. Biol Psychiatry. 1980 Oct. 15(5):813-7. [Medline].
Barton CH, Sterling ML, Vaziri ND. Rhabdomyolysis and acute renal failure associated with phencyclidine intoxication. Arch Int Med. 1980. 140(4):568-569.
Bey T, Patel A. Phencyclidine intoxication and adverse effects: a clinical and pharmacological review of an illicit drug. Cal J Emerg Med. 2007 Feb. 8(1):9-14. [Medline].
Corales RL, Maull KI, Becker DP. Phencyclidine abuse mimicking head injury. JAMA. 1980 Jun 13. 243(22):2323-4. [Medline].
Crider R. Phencyclidine: changing abuse patterns. NIDA Res Monogr. 1986. 64:163-73. [Medline].
Fauman B, Baker F, Coppleson LW, Rosen P, Segal MB. Psychosis induced by phencyclidine. J Am College Emerg Med. 1978. 4(3):223-225.
Giannini AJ, Loiselle RH, Price WA, Giannini MC. Chlorpromazine vs. meperidine in the treatment of phencyclidine psychosis. J Clin Psychiatry. 1985 Feb. 46(2):52-4. [Medline].
Johnston LD, O'Malley PM, Bachman JG, Schulenberg JE. Various stimulant drugs show continuing gradual declines among teens in 2008, most illicit drugs hold steady. University of Michigan News Service, Ann Arbor, MI. Dec 11, 2008. Available at http://www.monitoringthefuture.org. Accessed: 02/04/2009.
Koek W, Woods JH. Correlations between phencyclidine-like activity and N-methyl-D-aspartate antagonism: behavioral evidence. Sigma and Phencyclidine-like Compounds as Molecular Probes in Biology. Ann Arbor, Mich: NPP Books; 1988.
Lundberg GD, Gupta RC, Montgomery SH. Phencyclidine: patterns seen in street drug analysis. Clin Toxicol. 1976. 9(4):503-11. [Medline].
McCarron MM, Schulze BW, Thompson GA, Conder MC, Goetz WA. Acute phencyclidine intoxication: clinical patterns, complications, and treatment. Ann Emerg Med. 1981 Jun. 10(6):290-7. [Medline].
Meyer JS, Greifsenstein F, Devault M. A new drug causing symptoms of sensory deprivation. J Nerv Ment Dis. 1959. 129:29-40.
Olney JW, Labruyere J, Price MT. Pathological changes induced in cerebrocortical neurons by phencyclidine and related drugs. Science. 1989 Jun 16. 244(4910):1360-2. [Medline].
Pestaner JP, Southall PE. Sudden death during arrest and phencyclidine intoxication. Am J Forensic Med Pathol. 2003 Jun. 24(2):119-22. [Medline].
Petersen RC, Stillman RC. Phencyclidine: an overview. NIDA Res Monogr. 1978 Aug. 1-17. [Medline].
Phillips WA, Silverstein SM. Convergence of biological and psychological perspectives on cognitive coordination in schizophrenia. Behav Brain Sci. 2003 Feb. 26(1):65-82; discussion 82-137. [Medline].
Prochaska JO and DiClemente CC. Transtheoretical therapy: Toward a more integrative model of change. Psychotherapy Theory, Research and Practice. 1982. 19:276-288.
Sena SF, Kazimi S, Wu AH. False-positive phencyclidine immunoassay results caused by venlafaxine and O-desmethylvenlafaxine. Clin Chem. 2002. 48(4):676-7. [Medline].
Shulgin AT, Mac Lean DE. Illicit synthesis of phencyclidine (PCP) and several of its analogs. Clin Toxicol. 1976. 9(4):553-60. [Medline].
Stockard JJ, Werner SS, Aalbers JA, Chiappa KH. Electroencephalographic findings in phencyclidine intoxication. Arch Neurol. 1976 Mar. 33(3):200-3. [Medline].
Tennant FS Jr, Rawson RA, McCann M. Withdrawal from chronic phencyclidine (PCP) dependence with desipramine. Am J Psychiatry. 1981 Jun. 138(6):845-7. [Medline].
Weiss CJ, Millman RB. Hallucinogens, phencyclidine, marijuana, inhalants. Clinical Textbook of Addictive Disorders. New York, NY: Guilford Press; 1991.
Wong LK, Biemann K. Metabolites of phencyclidine. Clin Toxicol. 1976. 9(4):583-591.
Yago KB, Pitts FN Jr, Burgoyne RW, Aniline O, Yago LS, Pitts AF. The urban epidemic of phencyclidine (PCP) use: clinical and laboratory evidence from a public psychiatric hospital emergency service. J Clin Psychiatry. 1981 May. 42(5):193-6. [Medline].
Ziedonis D, Wyatt S. Psychotic Disorders. Principles of Addiction Medicine. 2nd ed. American Society of Addiction Medicine: Chevy Chase, Md; 1998.
Zukin SR, Zukin RS. Phencyclidine. Substance Abuse: A Comprehensive Textbook. Baltimore, Md: Williams & Wilkins; 1992.