Extrapyramidal reactions and amine metabolites in cerebrospinal fluid during haloperidol and clozapine treatment of schizophrenic patients.

8 male schizophrenic patients participated in a double-blind, cross over study of the extrapyramidal side-effects of haloperidol and clozapine (acute dystonis, Parkinsonism and tardive dyskinesia), together with their effect on homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF). Haloperidol (9 mg/day) caused Parkinsonism, reduced tardive dyskinesias and increased the HVA concentration in the CSF. Clozapine (225 mg/day) had no effect on the neurological phenomena but reduced HVA and 5-HIAA concentrations in the CSF. During the discontinuation phase following the administration of haloperidol, tardive dyskinesia occurred or was aggravated; this did not occur after administration of clozapine. Accordingly, it is suggested that clozapine does not induce dopaminergic hypersensibility and, therefore, will not induce tardive dyskinesias.