Immediate and delayed memory performance in schizophrenia spectrum patients: use of matched tasks

Rapid forgetting has been observed in long-term schizophrenic patients in the past. In this study, the rate of forgetting was assessed in short-term schizophrenic, schizophreniform and schizoaffective patients who had positive symptoms in the past, and in schizophreniform patients who never had positive symptoms. Four groups of patients representing these distinctions and a group of normal controls were assessed using immediate and delayed recall tasks, while controlling for effects of discriminating power of tasks, using matched-task methodology. The results showed that all schizophrenia spectrum patients with positive symptoms showed rapid forgetting as compared to schizophreniform patients with negative symptoms and normal controls. It is concluded that better immediate than delayed recall characterizes schizophrenia spectrum patients who have had positive symptoms. However, schizophrenia spectrum patients with negative symptoms may be qualitatively different from patients with positive symptoms in showing a slower rate of forgetting. The results support the hypothesis that there is at least one and possibly two brain dysfunctions affecting memory in schizophrenia.