Amphetamine induced psychosis has for the past 30 years provided a useful model for the study of schizophrenia. The amphetamine model, however, has been shown to have a number of shortcomings including an inability to model the deficit symptoms of schizophrenia. PCP (phencyclidine) has been shown to be capable of inducing a schizophreniform psychosis consisting of both productive and defict symptomatology. PCP induced psychosis, therefore, may provide a useful model of schizophrenia. This paper reviews the literature concerning the PCP model of schizophrenia and provides some independent confirmation of the ability of PCP to modulate mesocortical dopaminergic activity. Since PCP appears to mediate its CNS effects via a subclass of glutamate receptors, a possible glutamate theory of schizophrenia is proposed.