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Phencyclidine (PCP)-Related Psychiatric Disorders Clinical Presentation

  • Author: Alan D Schmetzer, MD; Chief Editor: Iqbal Ahmed, MBBS, FRCPsych(UK)  more...
Updated: Dec 29, 2015


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.

Contributor Information and Disclosures

Alan D Schmetzer, MD Professor Emeritus, Department of Psychiatry, Indiana University School of Medicine

Alan D Schmetzer, MD is a member of the following medical societies: American Academy of Addiction Psychiatry, American Academy of Clinical Psychiatrists, American Academy of Psychiatry and the Law, American Association for Physician Leadership, American Medical Association, American Psychiatric Association, International Society for ECT and Neurostimulation, American Neuropsychiatric Association

Disclosure: Nothing to disclose.


David R Diaz, MD, DFAPA Associate Professor of Clinical Psychiatry, Indiana University School of Medicine; Medical Director, Unit 3C, Larue D Carter Memorial Hospital

David R Diaz, MD, DFAPA is a member of the following medical societies: Academy of Psychosomatic Medicine, American Psychiatric Association, Indiana State Medical Association, National Hispanic Medical Association, Indiana Psychiatric Society, Indianapolis Medical Society

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Iqbal Ahmed, MBBS, FRCPsych(UK) Faculty, Department of Psychiatry, Tripler Army Medical Center; Clinical Professor of Psychiatry, Uniformed Services University of the Health Sciences; Clinical Professor of Psychiatry, Clinical Professor of Geriatric Medicine, University of Hawaii, John A Burns School of Medicine

Iqbal Ahmed, MBBS, FRCPsych(UK) is a member of the following medical societies: Academy of Psychosomatic Medicine, American Neuropsychiatric Association, American Society of Clinical Psychopharmacology, Royal College of Psychiatrists, American Association for Geriatric Psychiatry, American Psychiatric Association

Disclosure: Nothing to disclose.

Additional Contributors

Barry I Liskow, MD Professor of Psychiatry, Vice Chairman, Psychiatry Department, Director, Psychiatric Outpatient Clinic, The University of Kansas Medical Center

Disclosure: Nothing to disclose.

Roland McGrath, MD 

Roland McGrath, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.


The authors would like to acknowledge Indiana University School of Medicine, William Niles Wishard Memorial Hospital, and Larue D. Carter Memorial Hospital for their support of the faculty involved in the preparation of this Medscape Reference article.

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PCP molecule.
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