The prolactin and cortisol responses to dexamethasone (0.5 mg) were studied in combat veterans with (n = 18) and without (n = 12) posttraumatic stress disorder (PTSD) and normal controls (n = 18). Both veteran groups demonstrated greater prolactin suppression than the normals. In contrast, only veterans with PTSD showed an enhanced cortisol suppression in response to dexamethasone. These findings suggest that the prolactin response to dexamethasone may reflect a feature of combat exposure rather than PTSD per se.