I believe past trauma is the root cause and I doubt people have depression if they haven't had some type of experience they would classify as trauma. I think one solution is defeating the trauma with after decoupling the negative thinking patterns. Another problem is I think the illness cannot be defeated in some rare circumstances. I think people get prescribed medication too often. Doctors use the diagnosis too often from my observation. Some have tried to label me with it, when I suffer from another illness "gender dysphoria" and I think that isn't right for them to do. I also think the diagnosis is too vague and should have classifications.
I believe more resources need to be put into educating people and how to approach mental health as important to physical health. When I grew up in the US, it was always about physical health and with a little sex education. Mental health might be even more important because it can prevent a person from having good physical health.