Identifying Non-Psychotic Cognitive Errors on the Wais-R: a Study of Borderline, Depressed and Normal Subjects.

Abstract

There has been little empirical study of the impact of non-psychotic psychopathology on cognitive functioning. Cognitive psychology has focused on normal and ideal cognitive functioning, while clinical psychology has focused largely on psychotic thinking processes. A measure that combines knowledge from both fields to evaluate non-psychotic thinking would allow empirical testing of common hypotheses about cognitive functioning in clinical groups. The hypothesis that borderlines manifest "intact" functioning on structured tests such as the Wechsler Adult Intelligence Scale - Revised (WAIS-R) is commonly stated, but has not been convincingly proven. On the basis of clinical presentation, there is reason to think borderline patients show subtle but significant nonpsychotic thinking errors which have not been categorized. This study tests a measure of non-psychotic thinking errors which includes six errors reflecting four areas of cognitive functioning: Attention and focusing, Categorical thinking, Causal and sequential reasoning, and Metacognition. The measure is applied to verbatim responses from seven WAIS-R subtests. The study shows acceptable interrater reliabilities for the measure and tests the hypothesis that borderlines will show "intact" thinking on the WAIS-R. Test protocols of twenty inpatient borderlines, thirteen inpatient Major Depressive Disorder subjects, and sixteen normal subjects were scored using the Coding Measure for Cognitive Errors. Rate and type of errors are compared across groups using an ANCOVA covarying for IQ. Overall, there are few significant differences among the groups. The differences that occur suggest borderlines show greater inconsistency on measures of metacognition. The study provides only preliminary support for the hypothesis that borderlines perform like normals on structured tests. There is reason to examine further borderlines' metacognitive abilities. The lack of group differences may reflect limitations of the coding measure. Until we can evaluate cognitive errors according to more specific subcategories of particular cognitive skills, and levels of pathological severity, we cannot definitively conclude that borderlines show "intact" thinking on the WIAS-R or that they do not differ from normals in rate or type of cognitive errors. The paper discusses ways to improve the coding measure for future use.