Hydrocortisone impairs working memory in healthy humans, but not in patients with major depressive disorder

Abstract

Several studies have shown that stress or the administration of glucocorticoids can impair hippocampus-based declarative memory retrieval and prefrontal dependent working memory performance in healthy subjects. Major Depressive Disorder (MDD) is often characterized by memory impairment and increased cortisol secretion. Studies indicate that the impairing effects of glucocorticoids on declarative memory performance are missing in patients with MDD. The purpose of our study was to investigate whether the finding of missing effects of acute cortisol administration on memory performance in MDD is also seen when examining prefrontal-based working memory. In a placebo-controlled study, 57 patients with MDD and 56 sex- and age-matched healthy control subjects received either placebo or 10 mg of hydrocortisone orally before memory testing. To test the verbal modality of working memory, the Word Suppression Test was applied with one negative and one neutral test part. After hydrocortisone intake, healthy subjects showed a significantly poorer working memory performance compared to placebo treatment when negative interference words were administered. In contrast, memory performance of MDD patients was not affected by hydrocortisone treatment. The missing effects of glucocorticoid administration on working memory in MDD might be interpreted in the context of reduced central glucocorticoid receptor function.