Post-traumatic stress disorder (PTSD) is a mental health condition that's triggered by a terrifying event. Symptoms may include flashbacks, nightmares and severe anxiety, as well as uncontrollable thoughts about the event. The diagnosis is based solely on psychiatric symptoms. Many patients also have endocrine features, including lack of REM sleep, hypertension, and a poor response to dexamethasone-suppressed ACTH challenge. These symptoms have been considered as sporadic independent features. In this concept paper, we propose that these features are not independent, but are all part of a self-reinforcing endocrine cycle. Ionotropin has a critical role in the cycle. An understanding of the cycle suggests several new potential therapies for PTSD and, potentially, a new insight into essential hypertension.