Neuropsychological Performance in Psychiatric Patients with or Without Documented Brain Dysfunction

Abstract

The current study examined neuropsychological performance of schizophrenic and depressed patients with and without structural or EEG signs of brain dysfunctioning. The neuropsychological test battery was designed to sample intellectual functioning, psychornotor skills, nonverbal memory, and novel problem solving ability. Patients were classified into four groups: schizophrenics without signs of brain d;ysfunctioning, schizophrenics with signs of brain dysfunctioning, depressed without signs of brain dysfunctioning, and depressed with signs of brain dysfunctioning. The Trail Making Test—Parts A & B, the difference between these two components of the Trail Making Test, the Word Fluency Test and a Laterality Index based on the age scale scores of the WAIS significantly discriminated between patients with and without brain dysfunction. Using these variables and a Linear Discriminant Function Analysis, we found that 84.5% of our subjects could be correctly classified. Substantially fewer patients could be correctly classified with respect to their psychiatric diagnosis (i.e., 66.7% correct classification). In fact, only the PIQ from the WAIS-R showed significant differences between the depressed and schizophrenic subjects. Poor neuropsychological performance was interpreted as showing more than the behavioral disorganization associated with psychiatric states and was felt to be related to the presence of objective signs of brain dysfunctioning.

Key Words:

• neuropsychology
• brain dysfunction
• psychiatric patients