The authors examined the effects of age on plasma cortisol
concentrations of 81 depressed men after dexamethasone administration.
Dexamethasone nonsuppression was significantly more frequent in patients
older than age 55 than those younger. Similarly, older patients had
significantly higher postdexamethasone cortisol concentrations than younger
patients at all time points sampled. These differences could not be
attributed to severity or to the prevalence of psychosis in older and
younger depressed patients.