On the nature of Wisconsin Card Sorting Test performance in schizophrenia.

Performance on the Wisconsin Card Sorting Test (WCST) is widely reported to be impaired in patients with schizophrenia. It has been hypothesized that the performance deficit on the WCST in schizophrenia is related to a dysfunction of the frontal lobe, specifically the dorsolateral prefrontal cortex. This hypothesis was tested by comparing a group of patients with schizophrenia to patients with low grade right or left frontal lobe tumors and a group of patients with non-frontal high grade tumors. The results demonstrated a remarkable similarity in performance on the WCST between patients with schizophrenia and patients with right frontal lobe tumors. Patients with left frontal lobe tumors, non-frontal tumors, and normal control subjects did not show the same pattern of performance. This study provides support for frontal lobe dysfunction in the symptomatology of schizophrenia.