Verbal working memory dysfunction in schizophrenia: use of a Brown-Peterson paradigm

Recent studies of schizophrenia have implicated deficits in processes related to working memory, but the cognitive features of these deficits have been incompletely characterized. We used a modified Brown-Peterson paradigm to compare working memory in patients with schizophrenia and in normal control subjects. Distractor conditions differed in processing demand, increasing in complexity from no distractor to counting backwards (serial threes). We found significant effects of group, of distractor condition, and of a group × distractor condition interaction. The significant interaction was the result of a more rapid decline in the performance of schizophrenic patients with concurrent articulation. In addition, the schizophrenic group also made significantly more intrusion errors. The study suggests that schizophrenic patients exhibit dysfunction of the verbal working memory system due to a diminution in its overall processing resources.