Decreased plasma brain-derived neurotrophic factor levels in schizophrenic patients with tardive dyskinesia: association with dyskinetic movements

Neurodegenerative processes may be involved in the pathogenesis of tardive dyskinesia (TD). Accumulating evidence suggests that brain-derived neurotrophic factor (BDNF) plays a critical role in the maintenance of functional neurons. The present study was to examine plasma BDNF levels and the relationship among BDNF level, psychopathological and tardive dyskinesia symptoms in schizophrenic patients with TD. Eighty schizophrenic patients with TD were compared with 45 schizophrenic patients without TD, as well as with 45 age-, sex-matched normal controls. The severity of TD was assessed using the Abnormal Involuntary Movement Scale (AIMS). The psychopathology of patients was assessed by the Positive and Negative Syndrome Scale (PANSS). Plasma BDNF levels were measured by sandwich enzyme-linked immunosorbent assay (ELISA). The results showed that the patients with TD had lower plasma BDNF levels than those without TD, and than that of normal controls. In the patients with TD, plasma BDNF levels was inversely correlated with AIMS total score, and with PANSS negative subscore. Female patients had significantly lower plasma BDNF levels than male TD patients. Our results suggest that decreased BDNF may play an important role in the pathophysiology of TD. There may be a relationship between decreased BDNF levels and dyskinetic movements associated with TD.