Phencyclidine (PCP): a dangerous drug, but useful in schizophrenia research.

Phencyclidine (PCP) is a dangerous drug, and the federal government has placed it on Schedule II of the Controlled Substance Act (see http:// www .mninter.net/-publish/csa2.htm#Schedule%20III). Typically, users smoke PCP, and it is often mixed with parsley, marijuana, or cocaine. Most researchers have conducted experiments on animals rather than on people, and a few have been done on persons diagnosed with schizophrenia, so answers to questions about its addictive potential or development of tolerance are not clear. In healthy volunteers, PCP can induce symptoms that mimic those of schizophrenia, lasting from a few days to more than a week. The neurotransmitter glutamate and N-methyl-D-aspartate (NMDA) appear to play a role in the mechanism by which PCP induces positive and negative schizophrenic symptoms and cognitive defects (D. C. Javitt & S. R. Zukin, 1991; A. Lahti, B. Koffel, D. LaPorte, & C. A. Tamminga, 1995; T. W. Robbins, 1990). Because PCP can induce symptoms that are almost indistinguishable from those associated with schizophrenia, further research may lead to new medications that could be helpful to people who do not respond to neuroleptics that are currently available.