The purposes of the present research were two-fold. First, the psychiatric and psychological status of a group of chronic schizophrenics (N = 66) was followed over a period of 8 years. These variables, as measured by the Malamud and Sands (8) psychiatric rating scale and the Wechsler Adult Intelligence Scale (WAIS), respectively, were found to undergo significant improvement during this period. Second, the Halstead-Reitan test battery and several other neuropsychological tests reported to be sensitive to central nervous system deficit were administered to the same group of chronic schizophrenics. With the exception of the sentence repetition test, the neuropsychological test performance of this group was grossly impaired. Reliability measures were obtained using a test-retest technique and these indicated that the test battery was highly reliable. The performance on the neuropsychological tests was found to be related to psychiatric status, certain demographic variables, and drug regime. The tests appeared to be more sensitive to the severity of the schizophrenic process than they were to the presence or absence of neurological deficit.
Klonoff et al. (1970) studied this question.