Mentioning my clinical depression in a statement of purpose I have been struggling with clinical depression for over an year now and that has affected my grades. Is it a good idea to mention that in a statement of purpose while applying to a university (for a M.Sc+Ph.D programme)?
No. It is not a good idea. These statements are to show your positives and potential. You are not cheating any one if you did not mention that. But no one asked you about your medical history.