Motility, Parkinsonism, and prolactin with thiothixene and thioridazine

Clinical impressions suggest that thioridazine hydrochloride produces fewer extrapyramidal effects and more sedation than thiothixene. These drugs were given, each for three weeks, to 15 chronic schizophrenic outpatients in a counterbalanced, double-blind, crossover study. Spontaneous locomotion was recorded with an unobtrusive actometer toward the end of each three-week drug period. Surprisingly, patients were significantly more active with thioridazine, whereas parkinsonian scores, prolactin levels, and Brief Psychiatric Rating Scale scores remained about equal with the two drugs; thioridazine's extrapyramidal side effects were not "atypical." There are some explanations for why common clinical impressions and recent rodent studies have not predicted these results.