Reduction in antipsychotic drug dosage in mentally handicapped patients. A hospital study.

An investigation in a large mental handicap hospital revealed that 24% of the in-patients were receiving antipsychotic drugs. Chlorpromazine and thioridazine prescriptions accounted for 62% of the total while 10% of patients received depot preparations. Fifty-five per cent of the patients receiving these drugs had no established psychiatric diagnosis; most of these could be categorised as having a behaviour disorder. Patients aged 30-50 received higher doses, and female patients received a significantly higher mean dosage than male ones. In the patients receiving neuroleptic drugs who had also been taking them four years previously, there was a significant reduction in the dosage of the drugs received and the extent of polypharmacy of these agents. A mandatory requirement to review all prescriptions annually, implemented in 1984, may be a reason for this.