This is an open-label, randomized control trial where patients (N=32) with schizophrenia or bipolar disorder are randomized to receive either sublingual dexmedetomidine or oral lorazepam monotherapy for the treatment of episodic agitation. For moderate agitation (PANSS-EC score ≥14 and \<20), patients will receive either sublingual dexmedetomidine 120mcg or oral lorazepam 2mg. For severe agitation (PANSS-EC ≥20), patients will receive either sublingual dexmedetomidine 180mcg or oral lorazepam 2mg. The PANSS-EC and ACES will be evaluated at baseline and after 15, 30, 60, and 120 minutes.