Musnad Abu Ya'la al-Mawsili 115:56

Ibrahim ibn al-Hajjaj narrated to us, Hammad narrated to us, from Qatadah, from Anas, that the Messenger of Allah (may Allah bless him and grant him peace) used to say: "O Allah, I seek refuge in You from leprosy, and mutilating diseases, and insanity, and the evil of illnesses."