Clinical and biochemical parameters during neuroleptic treatment. I. Investigations with haloperidol

26 patients with a paranoid-hallucinatory syndrome were treated with a fixed daily dose of haloperidol. Psychopathological symptoms and parkinsonism were studied before and during the treatment. HVA and 5-HIAA concentrations in CSF were determined immediately before and after 5 or 15 days of treatment. After 5 days of treatment a slight effect was observed on psychotic symptoms and on the extrapyramidal motor system, as well as an elevation of HVA and 5-HIAA concentrations in CSF. After 15 days of treatment the extrapyramidal and antipsychotic effects were significant, but the rise of HVA was smaller than after 5 days of treatment; 5-HIAA remained unchanged. These different time courses of the neuroleptic effects on psychopathological symptoms, on extrapyramidal system and on monoamine metabolites concentration in CSF could be interpreted as a development of drug tolerance in relation to the biochemical parameters.