Cortisol exerts effects on the brain via two different receptors, producing complex and sometimes opposite effects on the brain structures involved with the different cognitive functions.

To scrutinize the interrelationships between cortisol, cognition and dementia.

Review of the literature and new own findings.

Animal and clinical studies showed an association between increased cortisol and poorer overall cognitive performance, declarative memory, language, processing speed, executive functioning, spatial memory, as well as social memory. High cortisol may exhibit neurotoxic effects on the hippocampus, and exacerbate oxidative injury and amyloid β peptide toxicity. Increased CSF cortisol levels have been found in subjects with dementia and Mild Cognitive Impairment (MCI) due to Alzheimer's disease (AD) compared to control subjects with normal cognition. In MCI due to AD, high CSF cortisol may also predict a more rapid cognitive decline. Higher cortisol levels have been also observed in delirium. Increased cortisol levels interact with inflammatory mediators, neurotransmitters, and growth factors, and may mediate the effects of depression, stressful life events, and personality traits, sleep disturbances, and cardiovascular risk factor on cognitive performance and cognitive decline.

High cortisol levels may exert deleterious effects on cognition and exacerbate AD pathology. Further studies are needed to explore glucocorticoid-based interventions in the management of cognitive disorders.

The authors have not supplied their declaration of competing interest.