["More is less": a retrospective study of haloperidol dosages in acute schizophrenia]

With the background of a number of meta-analyses on the optimal neuroleptic dosages [1,2] the average daily dosage for the treatment of acute schizophrenic episodes recommended in the internal treatment guidelines of our psychiatric clinic was reduced from 24 mg to 15 mg haloperidol equivalent. In the present retrospective study it was investigated what effect this change in guideline had on the actual dosing behavior and on the efficacy and the side effect rate of the antipsychotic treatment. For this purpose all haloperidol treated patients of a two year interval prior to the change of the guideline (1987/88, n = 103) were compared with all treated of a two year interval (1991/92, n = 87) following it.

The evaluation of the treatment data showed that the dosing guideline was adhered to and in 1991/92 on the average actually only 15 mg haloperidol were prescribed daily in acute schizophrenic episodes. The antipsychotic efficacy was just as good under this dosage as under the average daily dose of 24 mg haloperidol given in the preceeding interval; the average time in hospital was even reduced from 76 to 67 days. Under the lower daily doses an additional medication with biperiden was less often required.

Average daily doses of 15 mg haloperidol appear to be at least equally as effective and more tolerable for the treatment of acute schizophrenic episodes than average daily doses of 24 mg haloperidol.