Cognition and HPA axis reactivity in mildly to moderately depressed outpatients: a case-control study

Patients with depression display neurobiological changes of the hypothalamic-pituitary axis as well as cognitive disturbances.

To assess any association between hypothalamus-pituitary-adrenal (HPA) axis reactivity and memory-related cognitive functions.

Depressed outpatients (n = 83, ICD-10) were group-matched to healthy controls (n = 33), and tested on a number of cognitive domains. Salivary samples were collected at awakening, 30 min later and at 22:00 h. At 23:00 h, the participants ingested 1.0 mg of dexamethasone, and three saliva samples were collected the following day at the same times.

Patients and controls did not differ on any memory-related cognitive skills. After dexamethasone the cortisol level was 1.7 nmol/l higher (95% CI 0.0-2.8, P = 0.05) in depressed patients compared with controls. In the control group, but not in the patients, a positive association between post-DST cortisol and Rey's Complex figure test (1.3; 95% CI 0.3-3.6; P = 0.02) was found. We found no significant associations between other memory functions and cortisol measures.

Contrary to our hypothesis, we found a positive association between cortisol levels after dexamethasone and visuo-spatial memory primarily driven by the healthy controls. Otherwise, no association were found between HPA axis reactivity and memory-related cognitive function.