A reboot of the previous thread, which had a few technical issues (thank you Xan and Justme). I am asking specifically of the origin of Clinical Depression, i.e. the formal medical condition. I understand even that type is subject to interpretation and subjectivity, but it is the best I can do right now, given the contentiousness and malleability of this issue. Basically I'm talking about the long-term, severe sort of depression, as opposed to a few days of melancholy or low mood, which are normal (unless frequent, at which point it is consisted Clinical Depression).