[Factors interfering with the dexamethasone suppression test]

The interpretation of the dexamethasone suppression test in endocrinology and psychiatry depends on several variables. False-positive results can be caused by stress, weight loss, alcohol withdrawal, treatment with diphenylhydantoin, phenobarbital, rifampicin, carbamazepine and lithium. Therapy with spironolactone, naloxone, alpha 1-mimetic agents and estrogen can be responsible for an increase in plasma-cortisol concentration. False-negative results are seen in patients with liver disease and can also result from therapy with benzodiazepines at high dosages, indomethacin and possibly methadone and ketoconazole.