Serum neuroleptic activities required to inhibit relapse in schizophrenic patients — A study by radioreceptor assay

Abstract

1. 1. The serum levels of antidopaminergic (anti-D 2), anti-alpha-adrenergic (anti-NA) and antiserotonergic (anti-5HT 2) activities of neuroleptics were determined in schizophrenic patients on maintenance treatment. 2. 2. The patients whose conditions remained stable had significantly higher serum levels of anti-D 2 and anti-5HT 2 activities than those who were considered to be in unstable conditions after a period of remission. 3. 3. However, the serum levels of anti-5HT 2 activity in patients whose conditions remained stable varied as much as those of anti-NA activities did, so it appeared that from a pharmacological viewpoint anti-D 2 activity of neuroleptics was the most important in preventing a relapse in schizophrenic patient. 4. 4. The serum levels of anti-D 2 activity required to prevent relapses differed for each neuroleptic. 5. 5. The frequency of side effects increased concordant with increasing serum levels of anti-D 2, anti-NA and anti-5HT 2 activities, and unfortunately even minimum effective serum levels of anti-D 2 activity elicited slight side effects in the majority patients.