Decreased BDNF levels in CSF of drug-naive first-episode psychotic subjects: correlation with plasma BDNF and psychopathology.

Brain-derived neurotrophic factor (BDNF), which plays an important role in neurodevelopmental plasticity and cognitive performance, has been implicated in neuropsychopathology of schizophrenia. We examined the levels of both cerebrospinal fluid (CSF) and plasma BDNF concomitantly in drug-naive first-episode psychotic (FEP) subjects with ELISA to determine if these levels were different from control values and if any correlation exists between CSF and plasma BDNF levels. A significant reduction in BDNF protein levels was observed in both plasma and CSF of FEP subjects compared to controls. BDNF levels showed significant negative correlation with the scores of baseline PANSS positive symptom subscales. In addition, there was a significant positive correlation between plasma and CSF BDNF levels in FEP subjects. The parallel changes in BDNF levels in plasma and CSF indicate that plasma BDNF levels reflect the brain changes in BDNF levels in schizophrenia.