The effect of stress on the dexamethasone suppression test

The dexamethasone suppression test (DST) was studied in 40 presurgical subjects and 20 controls. Cortisol plasma concentrations were measured before and after a nocturnal dose of 1 mg dexamethasone. Nineteen of the 40 patients (47.5%) failed to show a suppression of plasma cortisol after dexamethasone. Nonsuppression on the DST was associated with a significantly higher baseline plasma cortisol concentration. Another putative indicator of emotional stress, the level of acute anxiety, was also studied. There was a significant difference in the level of acute anxiety among suppressors, nonsuppressors, and controls--the level of anxiety in nonsuppressors being significantly higher than in controls. It is concluded that stress associated with a physical danger can be a cause of nonsuppression on the DST.