Depression isn't just feeling sad. It's not necessarily caused by anything external. You cannot necessarily just "figure out why" you feel bad; that's really not how it usually works.

> You cannot necessarily just "figure out why" you feel bad

Well, of course, if you anesthetize someone they can't feel anything. If you cut off the physical pathways of ""feeling sad"" then they can't feel sad, but is that really the same as "fixing" the reason for why they were feeling sad in the first place?

Unless the reason was that the physical causes are running haywire and making someone feel sad when they otherwise wouldn't, but how often is that just uhh a lazy scapegoat? "Oh this person has no reason to feel sad, something must be wrong in their brain"

>It's not necessarily caused by anything external. Y

Then how could a drug fix it? We're positing that there is not only a mechanism causing it, but that this mechanism can be manipulated external to their own self/agency/whatever.

I think that it is at least as absurd to posit that you can come up with one chemical substance or another that will alleviate their depression when you dismiss the idea of coming up with a sequence of words spoken to them that might alleviate their depression. It's the conceit that we have a better idea of how their brains work chemically than we do of how their brains work cognitively.