Abstract
This study, made on 60 chronic mental patients, had aimed to determine the effective dosage of trihexyphenidyl, an antiparkinsonian drug. During the preliminary period all patients were given a standard medication consisting of a neuroleptic, trifluoperazine 60 mg. daily, and an antiparkinsonian agent, trihexyphenidyl 10 mg. daily. A placebo was substituted for the antiparkinsonian during the first experimental period to measure the patients' extrapyramidal sensitivity. This evaluation was performed with a rating scale (B.E.P.) and observations from the nursing staff.
Patients were divided into three groups of 20 according to their B.E.P. score and received one of the three therapeutic regimens: trihexyphenidyl 15 mg. or 6 mg. or placebo.
Analyses of the results allow us to conclude that for this population a daily dosage of 6 mg. of trihexyphenidyl gives as much protection as 15 mg.; patients receiving an antiparkinsonian agent needed less “p.r.n.” administration of prociclydine. We have also found that if the antiparkinsonian drug can control some extrapyramidal symptoms it might be responsible for the presence of other more complex neurological symptoms.