Relevance of Brain-derived Neurotrophic Factor Levels in Schizophrenia: A Systematic Review and Meta-Analysis

Abstract

Background: Brain Derived Neurotrophic Factor (BDNF) is one of the neuromodulators crucial for the survival, development and function of neurones in the brain and nervous system. Several authors linked its changes in production and concentration to Schizophrenia syndromes. Aim: This systematic review examined the available evidence to clarify the association between plasma BDNF levels and Schizophrenia. Method: Initial searches revealed 266 records. After screening of abstracts, 20 studies were selected. Following a preliminary review, 14 studies were included in this systematic review and meta-analysis. Results: Of the 14 studies (910 patients, 717 controls) 8 reported decreased BDNF levels in patients with schizophrenia as compared to controls; 3 studies (274/128) found increased BDNF levels; while 3 (62/62) reported no group differences. Meta-analysis of all pooled studies confirmed reduced BDNF levels in schizophrenia versus controls (medium effect size); however, the group difference was not significant when studies using unmedicated cases were considered. Conclusion: The cumulative evidence indicates reduced BDNF levels existing in schizophrenia. However, findings are less clear in unmedicated cases, suggesting that reduced BDNF levels in schizophrenia may be associated with symptom chronicity and/or chronic effects of antipsychotic medication.

Keywords

• BDNF
• neurones
• neuromodulator
• development
• function
• schizophrenia
• serum
• plasma
• levels
• brain derived neurotrophic factor