Personally, I wouldn't disclose ****. I'd ask upperclassman first to see, then I might ask admin about what they're doing with this data. You can even mention that your friends at other schools don't disclose this.
This is sketchy. These schools increasingly are looking for leverage against their students and like others have mentioned, they can use it against you. Even a kid in my first year class was withheld from running for elected office for school government during first year because of his mental health illness, that's literally what the school cited. They of course mentioned that they want him to be able to focus and succeed in school and academics and that should be priority 1. Which was a nice way to say, your anxiety disorder is a problem and you can't run for class president because of it.
If you have learning disabilities, sure. Because disclosing that could be used to get you more time to take exams, taking them in separate rooms, etc. But if you have a history of substance abuse, anxiety disorders or mood disorders, or psychotic disorders, or even take any psychiatric medicine, I'd leave it blank.
I can't think of a reason why they need to know that.
Edit: and ALWAYS visit the doctors that aren't associated with the school, if at all possible.