WHAT DETERMINES WISCONSIN CARD SORTING PERFORMANCE IN SCHIZOPHRENIA

Deficient performance on the Wisconsin Card Sorting Test (WCST) by patients with schizophrenia is a consistent finding. Although the test has been found sensitive to frontal lobe damage in neurological patients, it is not certain whether WCST performance in schizophrenia is caused by a structural abnormality in the frontal lobe. No differences in WCST performance between patients with schizophrenia and depression have yet been documented It is not impossible, however, that more detailed analyses of response patterns will reveal different information-processing strategies by these groups. Future studies need to confirm and explain the fact that not all schizophrenic patients have difficulty with the test, and that some seem to be able to improve performance following brief training. Little is known about the psychometric properties of the WCST Several different versions exist, and continue to be used. These versions are probably not interchangeable. Automated WCST versions should also be checked for differences with the "standard" version because small alterations have been found to influence performance. Methodological aspects of using the WCST in psychiatric populations are discussed. Thus far, research in schizophrenia may have focused too much on the perseverative error score in an attempt to find clear and qualitative differences between experimental groups. There has been a relative neglect of the possibility that some differences may be quantitative rather than qualitative.