Pathophysiology
There are a number of biological features that may distinguish PMD from NPMD. The most significant difference may be the presence of an abnormality in the hypothalamic pituitary adrenal (HPA) axis. The HPA axis, which is sometimes referred to as the stress hormone axis, appears to be chronically over-activated in PMD. Other abnormalities found in PMD include sleep abnormalities and changes in other areas of brain function. Finally, the incidence of psychotic depression has been reported to increase when the barometric pressure is low.
Read more about this topic: Psychotic Depression