In this double-blind six-week study, 98 chronic schizophrenic patients
receiving long-term neuroleptic treatment and trihexyphenidyl were switched
to either placebo or study trihexyphenidyl. Fifty-one (68%) of the 75
patients given placebo versus 1 of the 23 patients who continued on active
trihexyphenidyl developed severe worsening of extrapyramidal signs,
necessitating early termination from the study. Twenty-one (28%) of the
placebo patients versus 2 (8.7%) of the trihexyphenidyl patients developed
less severe worsening. Furthermore, 50 (66.6%) of the placebo patients but
only 2 (8.7%) of the trihexyphenidyl patients had psychotic or other severe
physical symptoms related to withdrawal of prestudy antiparkinsonian
medication. The authors conclude that these data support the need for
continuous use of antiparkinsonian medication in the long-term neuroleptic
therapy of chronic schizophrenic patients.Abstract Teaser