Risk and Prognostic Factors 
There is little information about risk factor s for phencyclidine use disorder. Among indi-
viduals admitted to substanc e abuse treatment, those for whom phencyclidine was the
primary substance were younger than those admitted for other substance use, had lower
educational levels, and were more likely to be  located in the West and Northeast regions of
the United States, compared with other admissions. 
Culture-Related Diagnostic Issues
Ketamine use in youths ages 16–23 years ha s been reported to be more common among
whites (0.5%) than among other ethnic gr oups (range 0%–0.3%). Among individuals ad-
mitted to substance abuse treatment, those for whom phencyclidine was the primary sub-
stance were predominantly black (49%) or Hispanic (29%).
Gender-Related Diagnostic Issues
Males make up about three-quarters of those with phencyclidine-related emergency room
visits.
Diagnostic Markers
Laboratory testing may be useful, as phencyclidin e is present in the urine in intoxicated in-
dividuals up to 8 days after ingestion. The in dividual’s history, along with certain physical
signs, such as nystagmus, analgesia and pr ominent hypertension, may aid in distinguish-
ing the phencyclidine clinical picture from that of other hallucinogens. 
Functional Consequences of Phencyclidine Use Disorder
In individuals with phencyclidine use disorder, there may be physical evidence of injuries
from accidents, fights, and falls. Chronic use of phencyclidine may lead to deficits in mem-
ory, speech, and cognition that may last for months. Cardiovascular and neurological tox-