Proactive interference and the neuropsychology of schizophrenia

Gray, Felden, Rawlins, Hemsley & Smith (1991) have proposed a theoretical model of the neuropsychology of schizophrenia. A major feature of this model is that it is a weakening of the influences of memories of previous input on current perception/learning which is basic to the phenomenon of acute schizophrenia. In the present study, proactive interference (PI) was used as a paradigm to test this hypothesis. PI occurs when new learning is diminished as a consequence of previously learned material. According to our reading of the Gray et al. (1991) model, acutely ill unmedicated patients with schizophrenia should demonstrate reduced PI relative to controls. Ten acutely ill unmedicated patients with schizophrenia, 20 patients suffering from major depressive disorder, and 20 healthy controls were assessed using a PI paradigm. No significant differences in PI emerged between the groups. The results do not support this specific feature of the neuropsychological model of acute schizophrenia proposed by Gray et al. (1991).