1. Twenty-one patients with post-traumatic stress disorder (PTSD) were included in a study utilizing baseline rapid eye movement (REM) latency measurements, the dexamethasone suppression test (DST), and the protirelin (thyroid releasing hormone; TRH) stimulation test. The DST and TRH stimulation test were repeated after double blind treatment with desipramine. 2. A high number of patients (75%) exhibited a REM latency of 60 min or less and blunted thyroid stimulating hormone (TSH) response to TRH (61.9%) on baseline tests while only one patient showed cortisol escape from dexamethasone suppression. 3. After four weeks of desipramine treatment, significant improvements were reported in the Hamilton Rating Scale for depression, but not for anxiety symptoms, PTSD symptoms, or self-rated depressive symptoms. 4. Desipramine treatment did not affect hormonal responses to TRH. 5. The findings of shortened REM latency and altered TRH stimulation test suggest PTSD and depression may share some pathophysiological abnormalities.