Abstract

The purpose of this study was to investigate the characteristics of cognitive deficits in positive and negative schizophrenic patients on tests of memory performance and memory organization. Positive schizophrenics, negative schizophrenics, nonschizophrenics and normals were administered multi-trial word list learning procedures. The findings of the study were : 1) positive schizophrenics were unimpaired on recognition test, and showed explicit impairment on recall and cluster tests related to memory organization, but positive schizophrenics and nonschizophrenics didn't show any significant difference in memory performance; 2) the positive schizophrenics, as well as normals and nonschizophrenics were able to organize semantically related words and improved clustering scores in trials with lists presented in categorized and uncategorized fashion; 3) negative schizophrenics were impaired on recall, and recognition test regardless of memory organization; and 4) the normals, nonschizophrenics and positive schizophrenics were able to organize semantically related words in trials, but negative schizophrenics were not able to organize semantically related words which presented in unorganized fashion. These results imply that the positive and negative schizophrenics are in the same diagnosis category, but are explicitly different in the pathological process and the cognitive deficits. The validation of heterogeneity in schizophrenics is discussed for future study.