Differential cognitive deficits in the neuropsychology of schizophrenia

Controversy concerning interpretation of neuropsychological findings in schizophrenia fan partly be attributed to use of tests lacking in accepted factor structure and having widely varying norming populations, sensitivity, and specificity. The Woodcock-Johnson (WJ-R) overcomes many of these psychometric weaknesses by providing seven co-normed cognitive factor scores covering a wide range of cognitive domains, thereby allowing for the rigorous determination of individual strengths/weaknesses. We administered it with traditional neuropsychological batteries to 30 schizophrenic patients. WJ-R data suggest: (1) average premorbid achievement; (2) general decline across factors: (3) differential weaknesses in processing speed and memory; (4) substantial within-subject heterogeneity across cognitive factors; and (5) substantial within-factor homogeneity across subjects. Stepwise regression of the WJ-R factors using traditional test batteries suggests that they have neuropsychological validity and psychometric advantages.