[Freegile]

So has it been studied? Are there popular theories on what the mechanics behind depression are? I would be curious to know these.

Both, headaches and depression to me seem to have been "intentionally" developed by evolution. Pain has a reason: Tell you to not do certain things. Low energy / self esteem might also have a reason: Tell you to stay at home.

A broken leg on the other hand was not developed for a reason by evolution.

[ronyfadel]

Sapolsky on depression: https://youtu.be/NOAgplgTxfc

“Depression is agression turned inwards”.

He explains what our current understanding of depression is. I think you’ll have a whole new understanding of depression after watching this.

[dependsontheq]

Evolution was no longer a factor as soon as we developed a complex society. So depression as an illness of the highly developed brain that has several layers of consciousness should probably not be compared with something like that and even if you do compare it, cancer has a clear cut evolutionary case why it’s happening. Do you want cancer? The evolutionary outcome is not really helpful from an individual perspective.