Twenty patients aged 17-67 years, who had previously been included in an open study of pimozide and who had shown improvement in interest and activity and in whom psychotic symptoms had been adequately controlled, were selected for a double-blind study of pimozide and placebo.
The daily dose was 3 nig and the duration of treatment eigth weeks. Interest and activity of the patients were evaluated every two weeks and psychotic symptoms at the start and at the end of the trial period. Ten patients received pimozide and ten placebo.
The obtained degree of improvement in interest, activity and psychotic symptoms in pimozide-treated patients was almost maintained throughout the eigth-week study period.
In the placebo-treated patients a significant decrease in activity and interest together with an increase in autism had occured by the end of the study. Side-effects were not observed.