Depression is mental, it's classified as a mental illness, not a physical illness, it just can have physical causes and symptoms. Not really a better classification than real/false depression.
I clearly referred to scientific studies, I can provide links if you'd like, extremely easily. I'm not sure how easily available they will be as they tend to be in academic/professional journals which require subscription, so it's possible you would only be able to read the abstract. I can access the vast majority through my university. If that isn't using scientific evidence then I don't know what is. And that comment itself tells me that there's no point even debating this with you.
