The difference in change of plasma cortisol after dexamethasone suppression test between positive and negative schizophrenics

Abstract

Schizophrenics have repeatedly shown deficient performance on memory measures. Of particular interest is whether they demonstrate exaggerated rates of forgetting which are not due solely to impaired acquisition of information. Neuropsychological performance o fg l first-episode schizophrenics and 32 healthy controls was compared. After finding memory to be the most discriminating of six domain scores (language, memory, attention, executive, motor, and visuospatial), we examined the specific memory measures which contributed to this effect. These included immediate and delay indices on measures from the Wechsler Memory Scale Revised (WMS-R), California Verbal Learning Test (CVLT), and ReyOsterrieth Complex Figure Test. MANOVA with modality (verbal, nonverbal) and delay as within-subjects factors showed a significant group by delay interaction (F(1,97) = 4.92; p < 0.029), which reflected significantly greater deficits in schizophrenics after the delay on Visual Reproduction of WMS-R, CVLT total recall, and Rey-Osterrieth. No effects of modality were observed, in further analyses, possible effects of differential learning were controlled by matching schizophrenic and control samples on initial recall scores. Schizophrenics exhibited significantly impaired performance on WMS-R subtests Logical Memory (paragraph recall) (F(1,46) 4.51; p < 0.039) and Visual Reproduction (F(1,58) = 4.21; p < 0.045), and on the Rey-Osterrieth, using copy score as an index of acquisition (F(1,54) ~ 10.76; p < 0.002). The results suggest that schizophrenic memory deficits are not entirely explained by impaired acquisition, but extend to retentinn of information in both verbal and nonverbal domains.