I don’t think telling schools you were hospitalized for a suicide attempt is a good idea. It will make them less likely to admit you. I’d stick with having been hospitalized for X period of time without giving the specific reason, and also be fairly general with illness of a close family member. TMI doesn’t get you points in this situation. Be sure you also apply to schools that match your actual stats, not just ones that match the stats you’d aspire to if these things hadn’t happened.
You could put a note at the end of the essay, or if there is an Additional Infornation section, put it in there. But you can’t realistically expect it to boost your chances much, if at all.