GLUCOCORTICOID INTERACTIONS WITH MEMORY FUNCTION IN SCHIZOPHRENIA

Glucocorticoid (GC) exposure can affect brain function, including pote ntial adverse effects on hippocampal physiology and on specific elemen ts of cognitive performance. In a prior study of healthy adult humans, decreased verbal memory performance was detected during four days of double-blind, placebo-controlled dexamethasone (DEX) treatment. Using an identical experimental design and sample size (n = 19), the cogniti ve effect of DEX treatment was studied in 11 subjects with schizophren ia, compared with 8 receiving placebo. In contrast to the effect in he althy adults, GC treatment with DEX at this dose (cumulative 3.5 mg) a nd duration did not decrease verbal memory performance or other measur es of cognitive function in the patients with schizophrenia. When data from this experiment was compared with data from the previous study o f healthy adults, covarying differences in baseline memory performance , a significant 3-way interaction was detected between subject group, treatment condition, and the repeated measurements of verbal memory pe rformance across baseline, treatment and washout (F[3,87] = 4.84, p = .0066), suggesting differential cognitive effects of DEX in the patien ts versus the previously studied healthy subjects. Baseline plasma cor tisol concentrations (0800h) prior to DEX treatment were inversely cor related with baseline delayed (r(s) = -0.536, p = .03) verbal recall p erformance, supporting a previous report. The current results await re plication using a larger sample size but provide preliminary evidence for an altered behavioral response to acute GC exposure in schizophren ic versus healthy subjects, and further evidence for a relationship be tween chronic changes in circulating cortisol and the memory impairmen ts found in this disorder. (C) 1998 Elsevier Science Ltd. All rights r eserved.