Cognitive impairment and cortisol resistance to dexamethasone suppression in elderly depression

The present study evaluates the relationship between cognitive impairment and the Dexamethasone Suppression Test (DST) in elderly persons suffering from depression. Twenty-nine subjects meeting DSM-III criteria for major depressive disorder (MDD) were assessed using the Global Deterioration Scale (GDS) and the DST. Plasma cortisol levels before and after receiving 0.5 mg dexamethasone were compared, and correlations were determined between GDS and postdexamethasone plasma cortisol levels. The results show that there is a positive correlation between the GDS scores and post-DEX cortisol levels (r = 0.57, p less than 0.005). It is suggested that increased activity of the HPA axis, seen in depression, could contribute to the cognitive impairments observed in this disorder.