Cortisol hypersecretion and cognitive impairment in depression.

We attempted to investigate the relationship between hypothalamic-pituitary-adrenal axis activity and cognitive function by measuring mean urinary free cortisol (MUFC) excretion and performance on the Halstead Category Test in depressed patients and normal controls. We observed a significant relationship between category test errors and MUFC in the depressed patients, but not in the controls. While an even more robust correlation was observed between age and category test errors in the patients, it appeared that age and depression interacted to produce severe cognitive impairment. Depression-related cortisol hypersecretion or its underlying determinants may contribute to depression-related cognitive dysfunction.