Cocaine-induced psychosis and PCP-induced psychosis each resemble some symptoms of schizophrenia but differ in their specific features. In a retrospective study of 34 male crack-cocaine-dependent patients without other psychiatric disorders and 16 actively psychotic men with schizophrenia, certain First Rank Schneiderian Symptoms such as thought broadcasting and thought withdrawal were more common in the schizophrenic group. In a separate group of 22 cocaine addicts with past use of both cocaine and PCP, the frequency of these symptoms during intoxication was similar for both drugs.
MK-801, a compound that blocks NMDA glutamate receptors, causes hyperactivity, repetitive behaviors, and explosive jumping (popping) in mice. A computerized system was developed to automatically measure popping and hyperactivity by detecting vertical platform movements. This method quantifies the number, force, and duration of jumps more precisely than human observation. The antipsychotic haloperidol significantly reduced both popping and hyperactivity caused by MK-801. The authors suggest this automated approach could improve preclinical screening of potential antipsychotic drugs and help clarify the mechanisms behind MK-801-induced behaviors.