A couple of years ago The Atlantic published an essay about research on creativity and mental illness with an emphasis on the work of Nancy C. Andreasen. One conclusion of Andreasen's research is that creative people tend to have mental illness in their families, even if they themselves do not (and many do). Why this is the case seems to derive from the way that creative people think. They are good as associating ideas with other ideas, which can be both helpful and not helpful to mental health. Associations are not always practical, understandable to others, or even correct.
Andreasen makes other generalizations about creative people that, unlike mental illness, are qualities somewhat under an individual person's control. Her creative people work hard, probably because they are doing what they like to do. They tend to be self-taught in some areas of knowledge, even if they have a great deal of formal education, and they tend to be interested in many different areas. Creative people take risks, and they are persistent in the face of rejection or failure. Andreasen defines creativity in a way that embraces the arts and sciences equally. John Nash, for example, the subject of the film A Beautiful Mind, was of particular interest to her. (Read her obituary about John and his wife Alicia).
Her most recent long-term study focuses on famously creative people, so her results may be skewed as a
result towards those people whose creative work has gained some mainstream acceptance and public accolade. Nevertheless, I think it is worth noting her generalizations and
think about their implications for people who are not famous.