Effects of stress hormones on the structure and function of the human brain.

In response to stress, the hypothalamus-pituitary-adrenal axis is activated and glucocorticoids are secreted. These hormones exert multiple effects in the periphery as well as the brain. Acutely, they enhance memory consolidation, but at the same time the ability to retrieve previously learned information is reduced. In addition, glucocorticoids appear to interfere with working (short-term) memory. Chronically elevated glucocorticoid levels, as a result of endocrine or psychiatric disorders or as part of age-associated changes in the hypothalamus-pituitary-adrenal system, mostly have a negative influence on memory. In parallel, structural alterations are observed in the hippocampus and the prefrontal cortex. However, it seems that plasticity/reversibility is more common than previously thought. Moreover, several pharmacological interventions in animal models or small-scale human studies have revealed promising results. The advanced understanding of the CNS effects of glucocorticoids will ultimately lead to progress in the treatment of psychiatric and systemic diseases characterized by hypothalamus-pituitary-adrenal hyper- or hypo-activity.