Serum neuroleptic levels and clinical outcome in schizophrenic patients treated with fluphenazine decanoate.

Serum neuroleptic levels were measured by radioreceptor assay in 24 schizophrenic patients maintained on fluphenazine decanoate. Clinical state was assessed at the time of neuroleptic level measurement and during the subsequent 6 months. Patients with persistent psychotic symptoms were on higher doses of fluphenazine decanoate than those in remission and had higher neuroleptic levels. Patients who relapsed during the 6 months after neuroleptic levels were measured did not differ in dose from those who stayed in remission but tended to have lower serum neuroleptic levels. These observations suggest that persistent psychotic symptoms in neuroleptic-maintained patients cannot be accounted for solely by inadequate treatment. Furthermore, in remitted patients serum neuroleptic levels may be a determinant of outcome.