Cognitive abnormalities in schizophrenic patients and schizotypal college students

Twenty schizotypal college students, identified by the MMPI-168, were compared with 127 institutionalized or postinstitutional psychiatric patients with chronic schizophrenia, 140 normal control subjects, and 19 students with nonschizotypal MMPI elevations. The comparison measures were indices of cognition derived from COGLAB, a multiparadigmatic cognitive test battery. COGLAB includes measures of preattentional, attentional, conceptual, and psychomotor performance. As expected, the patients were deficient on all but one of the measures. The nonschizotypic elevation group was not different from the normal control group. Schizotypal subjects were found to have deficits in three areas of information processing: preattentional processing, response biasing, and concept attainment and manipulation. However, their performance was just as good as and less variable than that of normal subjects on psychomotor and attentional tasks. The results do not support the hypothesis that schizotypy is characterized by pervasive cognitive deficits which are simply less severe than those of other psychiatric groups. Rather, there are discrete deficits in specific areas and possibly compensatory abnormalities associated with primary deficits. The results are further discussed with regard to the hypothesis that schizotypy shares a common neurophysiological and/or developmental substrate with more severe psychiatric disorders.