The effect of pimozide on CSF norepinephrine in schizophrenia.

The authors measured CSF norepinephrine concentrations in drug-free schizophrenic patients with and without probenecid administration and in drug-free normal control subjects. Schizophrenic patients had significantly higher baseline norepinephrine values. The dopamine metabolite homovanillic acid correlated significantly with norepinephrine. During chronic treatment with the neuroleptic pimozide, patients' norepinephrine levels were significantly decreased. The pimozide-induced decrease in norepinephrine, as well as the percent decrease, correlated significantly with the patients' decrease in global psychosis. These data are consistent with recent reports of elevated concentrations of norepinephrine in specific brain areas of schizophrenic patients, and they support a role for norepinephrine metabolism in the pharmacological effects of antipsychotic drugs.