The dexamethasone suppression test (DST) was administered to 28 male
combat veterans with posttraumatic stress disorder. Six subjects (21%) were
nonsuppressors. The nonsuppression rates for the subgroups with and without
major depressive disorder according to the Research Diagnostic Criteria
were 50% and 6%, respectively. The authors conclude that cortisol
nonsuppression is rare in posttraumatic stress disorder unless there is
concomitant major depression.