• Eighty newly admitted or readmitted men with DSM-III schizophrenia were assigned to receive 5, 10, or 20 mg/d of haloperidol for 4 weeks. Staff were not "blind" to dose. By Clinical Global Impression Scale ratings, the 20-mg dose appeared to be superior to both the 5- and 10-mg doses for the first 2 weeks of treatment but not thereafter. On the Brief Psychiatric Rating Scale Schizophrenia factor, the 20-mg dose was superior to the 5-mg dose throughout the trial and tended to be marginally superior to the 10-mg dose after the first 2 weeks of treatment. By the second week of treatment, however, the group receiving the 20-mg dose deteriorated significantly with regard to Brief Psychiatric Rating Scale ratings of Withdrawal-Retardation (blunted affect, motor retardation, and emotional withdrawal) as well as akinesia and akathisia ratings. Furthermore, 35% of patients given 20 mg/d of haloperidol insisted on leaving the hospital against medical advice vs only 4% of those given 5 or 10 mg/d of haloperidol. A 20-mg/d dose of haloperidol, therefore, may have substantial "psychotoxic" effects by the second week of treatment.
Van Putten T, Marder SR, Mintz J. A Controlled Dose Comparison of Haloperidol in Newly Admitted Schizophrenic Patients. Arch Gen Psychiatry. 1990;47(8):754-758. doi:10.1001/archpsyc.1990.01810200062009