Years ago there was a wild-looking bearded man who rode around the streets swearing loudly at everyone.I recognized him later as an inpatient at a psych hospital and asked someone who he was. To my surprise it turned out he was a Professor of Physics and a very successful author. He hadn't given off an impression of being smart. On the other hand some people assume that if you appear smart you can't have a mental health condition. Several people I know get that occasionally. But a lot of people with mental health conditions are highly intelligent or highly creative. There are lots of brilliant artists, musicians and writers. Often education or work is disrupted because times of ill health but some people still achieve great things. Of course not everyone is able to achieve these things. For some people dealing with their health is a full time job. Regardless of what they can or can't do, having a mental health issue doesn't mean a person is unintelligent and being intelligent doesn't mean you don't have mental health issues.