Levels of Serum Brain-Derived Neurotrophic Factor in Schizophrenia.

Recent meta-analyses of serum brain-derived neurotrophic factor (BDNF) have reported lower levels in patients with schizophrenia. However, most studies did not consider the potential confounding effects of time of collection, age, sex, smoking, and obesity. Here, we sought to examine differences in serum BDNF between medicated patients with schizophrenia compared with control subjects, taking into consideration the potential confounders of serum BDNF. Serum was obtained from a sample of fasted blood collected from all participants, and BDNF was assayed on a commercially available kit. After adjusting for potential confounders, there was no statistically significant difference between cases and control subjects (p = 0.261). In the model, body mass index emerged as the most significant predictor of serum BDNF (β = 0.22, p = 0.009). The present study did not support a role for serum BDNF as a biomarker in schizophrenia. This could be due to the nonspecific nature of serum BDNF and its association with both mental and physical conditions.