RESUMEN
Schizophrenia is a devastating psychiatric disorder whose pathophysiology has not been fully clarified yet. Although dopamine dysfunction in schizophrenia is unequivocal, there are many evidences suggesting the involvement of the glutamatergic system. This paper briefly describes some basic knowledge regarding the functioning of the glutamatergic receptors with emphasis on the N-methyl-D-aspartate (NMDA) receptors. Presents evidence for glutamatergic dysfunction in schizophrenia, more specifically NMDA receptor hypofunction. Finaly the paper discusses the interaction between the dopaminergic and the glutamatergic systems; in special how hyperdopaminergic state found in schizophrenia can be associated to glutamatergic dysfunctions.
Asunto(s)
Receptores de N-Metil-D-Aspartato/fisiología , Esquizofrenia/etiología , Humanos , N-Metilaspartato/agonistas , Receptores Dopaminérgicos/fisiología , Esquizofrenia/tratamiento farmacológicoRESUMEN
A esquizofrenia é um transtorno psiquiátrico devastador cuja fisiopatologia ainda está para ser esclarecida. Apesar de uma disfunção dopaminérgica estar bem estabelecida na esquizofrenia, há uma série de evidências sugerindo o envolvimento do sistema glutamatérgico na fisiopatologia do transtorno. Este artigo faz uma breve revisão de alguns aspectos básicos do funcionamento dos receptores glutamatérgicos com ênfase nos receptores N-metil-D-aspartato (NMDA). Apresenta evidências científicas sugerindo uma disfunção do sistema glutamatérgico na esquizofrenia (hipofunção de receptores NMDA). E discute as interações entre os sistemas dopaminérgico e glutamatérgico; mais especificamente como os estados hiperdopaminérgicos encontrados na esquizofrenia podem estar associados a uma alteração glutamatérgica
Asunto(s)
Humanos , Esquizofrenia/etiología , Receptores de N-Metil-D-Aspartato/fisiología , Esquizofrenia/tratamiento farmacológico , N-Metilaspartato/agonistas , Receptores Dopaminérgicos/fisiologíaRESUMEN
Depressive episodes are a common and potentially severe occurrence in schizophrenia but are poorly recognised by psychiatrists. Coherent diagnostic criteria are necessary to improve diagnosis and treatment of these conditions. To evaluate the usefulness of the ICD-10 category of post-schizophrenic depression (PSD) and the DSM-IV category of postpsychotic depressive disorder of schizophrenia (PDDS), 80 clinically stable schizophrenic outpatients were evaluated with two independent measures of depression, a dimensional measure and a categorical measure. One rater applied the DSM-IV criteria for major depressive episodes (MDE), and the other applied the Calgary Depression Scale for Schizophrenia, the Positive and Negative Syndrome Scale, and the Extrapyramidal Symptoms Rating Scale. Thirteen patients (16.3%) met criteria for MDE. All of them met the DSM-IV PDDS research criteria, but only two patients matched the ICD-10 PSD criteria, which require that the episode occurred in the 12 months after the last psychotic episode. There was no significant difference in the incidence of depressive episodes within 12 months after an acute psychotic episode and outside this time period. The data suggest that depressive episodes in schizophrenia are not restricted to the first year following the psychotic episode. Useful criteria for depressive episodes in schizophrenia should avoid a temporal relation with the psychotic episode.