dement (v.)
"to drive mad," 1540s, probably from Middle French démenter, from Late Latin dementare "to drive out of one's mind," from stem of Latin demens "out of one's senses, insane, raving, foolish; distracting, wild, reckless" (a less technical term than insanitas), from phrase de mente, from de + mente, ablative of mens mind" (see mind (n.)).