STUDY OF THE CLINICAL UTILITY OF RADIORECEPTOR ASSAY IN OUTPATIENTS WITH SCHIZOPHRENIA RECEIVING HIGH-DOSES OF NEUROLEPTICS

A radioreceptor assay (RRA) was used to determine the neuroleptic plas ma levels of 32 outpatients with schizophrenia receiving a high dose o f neuroleptics (the equivalent of 18 mg or more of oral haloperidol pe r day) and undergoing a 50% partial and progressive reduction (ten per cent each month for five months) in their medication. Plasma levels of neuroleptics were measured three times: before (T1) and immediately a fter the 50% reduction (T2) and five months later (T3). A linear corre lation was observed between neuroleptic plasma levels obtained by RRA and the neuroleptic doses prescribed at T1 and T3. Furthermore, neurol eptic plasma levels were significantly lower at T3 than at T1. Concurr ent evaluations of psychopathology were done using the Brief Psychiatr ic Rating Scale, and the results indicated that no correlation exists between neuroleptic plasma levels and the total rating scale scores at T1 but a significant correlation was observed at T3.