The effects of psychoactive drugs and neuroleptics on language in normal subjects and schizophrenic patients: a review

The aim of this survey is to present an overview of research into psychopha rmacology as regards the effects of different psychoactive drugs and neurol eptics (NL) on language in normal subjects and schizophrenic patients. Eigh teen studies that have investigated the effects of different drugs (alcohol , amphetamines, secobarbital, L-dopa, psilocybin, ketamine, fenfluramine) a nd neuroleptics (conventional and atypical) on language are reviewed. There are no studies concerning the effects of neuroleptics on language in healt hy subjects. The results of the effects of other molecules indicate that la nguage production can be increased (alcohol, amphetamine, secobarbital), re ndered more complex (d-amphetamine), more focused (L-dopa) or more unfocuse d (psilocybin) and clearly impaired (ketamine). For schizophrenic patients, most studies shaw that conventional neuroleptic treatments, at a therapeut ic dosage and in acute or chronic mode, reduce language disorders at all le vels (clinic, linguistic, psycholinguistic). In conjunction with other mole cules, the classical NL, when administered at a moderate dosage and in chro nic mode, modify language in schizophrenia, either by improving the verbal flow and reducing pauses and positive thought disorder (NL + amphetamine) o r by inducing an impairment in the language measurements (NL + fenfluramine ). Clinical, methodological and theoretical considerations of results are d ebated in the framework of schizophrenic language disorders. (C) 2000 Editi ons scientifiques et medicales Elsevier SAS.