Impairment of verbal memory and learning in antipsychotic-naı̈ve patients with first-episode schizophrenia

Abstract

Background: Verbal memory deficits are of interest in schizophrenia because of the potential relationship to functional and anatomic mesial temporal lobe pathology in this disorder. The goal of this study was to characterize the nature of verbal memory impairments in antipsychotic-naı̈ve schizophrenic patients early in the course of illness. Methods: Neuroleptic-naı̈ve patients with schizophrenia ( n=62) and healthy individuals ( n=67), matched on IQ, age, sex, and parental socioeconomic status, were administered the California Verbal Learning Test (CVLT). Results: Schizophrenia participants performed significantly worse than healthy individuals on measures of verbal learning, short- and long-term memory, and immediate attention. Deficits in recall were related to reduced use of organizational strategies to facilitate verbal encoding and retrieval. No group differences were found in rate of forgetting or susceptibility to proactive or retroactive interference. Memory deficits had minimal relation to positive or negative symptom severity. Conclusions: Schizophrenia is characterized by significant verbal memory dysfunction early in the course of illness prior to treatment with antipsychotic medications. Deficits in consistency of learning over several trials, as well as a strong relationship between semantic organizational strategies and reduced learning capacity, implicate prefrontal dysfunction as a contributor to verbal memory deficits in schizophrenia.