Prolactin plasma levels after neuroleptic challenge predict clinical response in schizophrenic patients
Abstract
Till now. the ability of prolactin (PRL) levels to predict treatment response during neuroleptic therapy has been explored with inconclusive results. Studies exploring PRL response in a test dose design are very scarce, PRL response to a chlorpromazine test dose failed to predict the outcome in a study by Meltzer et al. - We have investigated prolactin levels after a single oral dose of isofloxytepin or haloperidol in 29 schizophrenic patients, who were subsequently treated by the same neuroleptic. - In multiple regression analysis the set of 5 variables (baseline PRL level and PRL levels 2 and 6 hours after the test dose, drug group and sex) was significantly related to improvement (R2 = 0.69; F = 6.76; p = 0.0003).
Only baseline PRL and drug group did not contribute significantly, a significant interaction of drug group and PRL levels suggests a different relationship between improvement and prolactin elevation in each treatment group, partial coefficients of determination for PRL levels 2 and 6 hours after the challenge dose and for PRL treatment group interactions were all about 30 %. Patients improved after isofloxythepin had higher PRL levels (52.5 ng/ml) than non-improvers (16.5 ng/ml) after 6 hours.
Methodological constraints of the study and reasons for differences in relationships of prolactin and improvement in various patient groups are discussed