Semantic memory anomaly in first-episode schizophrenia patients

Abstract

Semantic memory abnormalities in chronic schizophrenia have been studied using a variety of paradigms. Previous studies using a semantic categorization task reported that patients exhibit an extension of the category boundary to semantically related items outside the category. We attempt to replicate the study in a sample of first episode patients. Forty-five first-episode DSM-IV schizophrenic inpatients were assessed at the time of admission (25 of them were medication-naȉve, 20 had received medication for a short period of time). They were assessed again after their symptoms were stabilized with conventional anti-psychotic medication. Compared with normal controls, medication-naȉve patients showed a similar reaction time (RT) profile in the categorization task, ie the borderline condition taking the longest. However, the recently medicated patients showed an increase in RT in the related condition. This increase normalized after the symptoms were controlled by longer treatment with anti-psychotic medication. These findings suggest that semantic memory abnormalities might not be detectable in all patients across different stages in their illness. There is also some suggestion that early changes in semantic system might be reversed by medication.