The above link talks about depression as an illness of the brain, like a heart defect or a sprained wrist. It is not the fault of the parents or caregivers, and it is not the fault of the one suffering.
There are always contributing factors, and research points to many of those, I’ll spare you for now but here’s a link that I found helpful.
Anyway, read the article at the top, and give it some thought. I have often told myself that there must be something wrong with me, but thinking about something being wrong with my brain somehow removes the shame…