Objectives: Evidence from clinical, pharmacological and animal studies, have led to neurodevelopment, neurodegeneration, and dopamine hypotheses, and to the investigation of BDNF as a potential candidate molecule in the pathophysiology of schizophrenia, The aim of this study is to investigate the BNDF levels of schizophrenic patients with depression and compare them with major depression patients and controls in order to understand the nature of depressive symptoms seen in schizophrenia. Methods: The BDNF levels of eight schizophrenic patients with depressive symptomatology (SD) were compared with two control groups. The first group consisted of major depressed patients (MDD) (n=24) and the second was the healthy control group (n=26). Results: SD group had BDNF levels similar to control group and MDD group had significantly lower levels than the other two groups. Conclusion: This difference of BDNF levels between schizophrenia with depression group and major depression group supports the hypothesis of distinct etiologies
