Neuropsychological impairment and associated intellectual functions in schizophrenic and other psychiatric patients.

As a routine admission procedure of an ongoing research program, the Halstead-Reitan Battery (HRB) and the Wechsler Adult Intelligence Scale (WAIS) were completed by 37 chronic schizophrenic patients, 3 patients with major affective disorders, and 2 with atypical psychoses. These admission data provided a basis for a retrospective investigation into the possibility of a relationship between impairment on the HRB and IQ. It was found that greater impairment on the HRB was associated with lower full-scale IQ (FSIQ) scores (r = -0.78, p less than .001). When the sample was separated into impaired and normal groups based on performance on the HRB, the coefficients of two discriminant functions, i.e., Verbal IQ and Picture Arrangement, classified the two groups with 100% accuracy. Cross-validation of the stepwise discriminant function analysis, using the jackknife procedure, resulted in a 98% hit rate. The results of the present study together with those of two other recent studies suggest that intellectual functions are critical interactive variables for interpreting the performance of chronic schizophrenic and other psychiatric groups on the HRB. Cautions to be observed in interpreting impaired and normal functioning in the context of intellectual functions are discussed.