If the cause is a disturbance in the serotonin or dopamine system, "positive things to focus on" don't do shit. It's similar with a thyroid hypofunction. I suffered immensely before I got my meds, slept 16 hours a day, unable to concentrate and incredibly depressed/suicidal.
As soon as I got a replacement for my missing hormones, it became better.
Please tell me again how drugs do not "solve depression" and just "numb" it.
Sure, there are cases where it's psychological, but it's by far not all or most of them.
This is why i said "mostly". I don't believe most depressed people have disturbance in their systems.