Clozapine versus chlorpromazine for the treatment of schizophrenia: preliminary results from a double-blind study.

Fifteen schizophrenic inpatients were treated in a double-blind comparison study of clozapine versus chlorpromazine. Clozapine appeared to be at least as effective as chlorpromazine without producing any extrapyramidal reactions. Although bone marrow toxicity associated with clozapine has led to the drug's withdrawal from clinical use, data from studies of clozapine demonstrate that a drug can be effective antipsychotic without producing neurologic reactions.