Cortisol and trait anxiety as relevant factors involved in memory performance in people with drug-resistant epilepsy

People with drug-resistant epilepsy are exposed to unpredictable and uncontrollable seizures, which can be considered as a chronic stress condition. Additionally, these patients present memory deficits and a high prevalence of depression and anxiety. Cortisol, the main stress hormone, has a modulatory role on memory in healthy individuals and patients with emotional disorders, but its role in memory and emotional processes remains unclear in people with epilepsy. This study analyzes the differences in cortisol levels in people with epilepsy with high and low memory performance, and the relationships among cortisol levels, epilepsy-related factors, memory, anxiety, and depression. Fifty-two adults with drug-resistant epilepsy underwent a neuropsychological evaluation, in which nine saliva samples were collected to analyze the ability of the hypothalamic-pituitary-adrenal axis to descend in accordance with the circadian rhythm. Cortisol area under the curve (AUC) was computed to study the global cortisol changes. Patients with low immediate and delayed memory performance and left-hemisphere focus showed higher cortisol levels. Additionally, patients with low memory scores had higher cortisol AUC, and therefore slower declining levels in the afternoon. Memory performance was negatively related to the cortisol AUC and trait anxiety, being both reliable predictors of memory performance, especially in patients with left-hemisphere focus. These results suggest that memory deficits in people with drug-resistant epilepsy may be influenced by exposure to cortisol derived from chronic stress. Additionally, trait anxiety could contribute to increasing the vulnerability to stress.