Melancholy can be a persistent state of disappointment that is the results of interaction between just one's inner Organic and psychological state and gets triggered of with environmental stressors. Reactive melancholy is in reaction to some situation like loss, sickness, trauma etcetera. Endogenous depression happens with no noticeable environmental stressors. https://rafaelbthui.governor-wiki.com/1808900/considerations_to_know_about_attentin