SYSTEMATIZED DELUSIONS AND NEUROPSYCHOLOGICAL FUNCTION IN PARANOID AND NONPARANOID SCHIZOPHRENIA

We extended research originating with the Tsuang-Winokur criteria for paranoid and nonparanoid schizophrenia. To partially resolve problems of subtype instability, 41 consecutive admissions meeting DSM-III-R cr iteria for schizophrenia were subdivided according to whether they eve r experienced prominent systematized delusions. Neuropsychological pro files for paranoid patients and nonparanoids with a history of systema tized delusions were extremely similar. When combined, this 'systemati zed' group had significantly better general verbal ability and verbal memory than patients who never manifested systematized delusions. Ther e was also a significant neuropsychological function-by-group interact ion. The neuropsychological data suggested that systematized patients had better premorbid cognitive functioning as well as a greater discre pancy between premorbid verbal ability and current attentional functio ning. No between-group differences were found on a measure of prefront al-executive function, nor were there any neuropsychological differenc es between traditionally defined (DSM-III-R) paranoid and nonparanoid subgroups. This study suggests a possible shift in the dividing line b etween paranoid and nonparanoid subtypes and illustrates the potential value of neuropsychological data for refining psychiatric nosologies.