Lewis & Short

dēmento, āre, 1, v. a. and n. [demetior].

  1. I. Act., to drive mad, to craze, deprive of mind: dementatus, Cassiod. Amic. 21: ἐξιστάναι ἰδιωτικῶς, Gloss. Graec. Lat.; esp. to bewitch, delude: propter quod magiis suis dementasset eos, Vulg. Act. 8, 11.
  2. II. Neut., to rave, be out of one’s mind: semper dementabat, Lact. Mort. Pers. 7, 9.