There's a strong bias toward assuming that an effective treatment must necessarily address the disease etiologically.
I remember readying a study that observed that something like 50% of depressive episodes in people spontaneously resolve within a year without any treatment whatsoever.
Obviously that makes things quite difficult. If one starts an antidepressant, and six months later, is free from depression, then what evidence is there that the antidepressant vs. time was the resolution?
Perhaps stopping the antidepressant would be an indication? But then again, any rebound depression might just be from the disruption in homeostasis that the body has become accustomed to from the antidepressant.
There is, however, a strong bias toward unnecessarily searching for a causal connection between treatment and disease, but also dismissing effective treatments where cause and treatment aren't sufficient connected in people's minds. eg: you're only treating the symptoms as if that can't substantially improve peoples' lives.