I have first hand experience. Also "depression" is different from "chronic depression". You can experience the former as the direct result of some cause.

Come on. Don’t roll into a conversation playing armchair expert criticizing others’ contributions when you’ve got nothing of substance to say.

You’re as capable of typing “causes of chronic depression” into a search bar as anyone else. The fact that you don’t do that indicates you don’t want to contribute. You just want to be argumentative.

Riveting discussion. How about you reply with something of substance instead of just presumptuous and pedantic quips.