Is mental illness a “real” disease?

It's a real disease, of course. But unfortunately, it's a huge misconception that people don't take it seriously and don't really consider it as a disease. People tend to invalidate these mental health issues because they're not aware how these illnesses can take a toll on a person. They believe that, "it's just in the head" and tend to say things like "be optimistic, don't be so negative", "you need to move on", "just get over it" which isn't really great. It's not just an excuse for dealing with things badly, it's something more than that. There's a malfunction in the brain how it should be sorting emotions and thoughts out and that's a serious problem.