In terms of writing your personal statement / or SOP, I heard it really might negatively affect you if you discuss your mental health (whatsoever - (stigmatized)) in your grad apps. I think you can disclose that you had health issues, but just don't get into it too much. (It's not the admission committee's business to judge based on mental health, so don't give them that chance to unfairly do so). Since masters/PhD programs are incredibly stressful and demanding, I've heard that people's applications have been tossed from discussing their mental health struggles, unfortunately. I can't speak for art-history since I am in the biological sciences, but I know that most programs look at your application holistically, and your research will be the #1 important thing in your application, if not the letters of rec. Most applications with a GPA above a 3.0 will be reviewed by most programs, I think.