SYNOPSISDuring 20 separate illnesses 17 severely disturbed manic patients were given either methysergide or thioridazine in a 21 day double-blind controlled trial. For most of the trial patients received either 9 mg methysergide or 450 mg thioridazine daily; during one 24-hour period 12 mg methysergide or 600 mg thioridazine was administered. Daily clinical assessments were made. Methysergide proved significantly less effective than the phenothiazine.