Increased plasma brain-derived neurotropic factor, not nerve growth factor-beta, in schizophrenia patients with better response to risperidone treatment

Background: Some neurotropins, including brain-derived neurotropic factor (BDNF) or nerve growth factor-β (β-NGF), play important roles in neurodevelopment and neuroprotection. We examined the plasma levels of these 2 factors in schizophrenia patients at the time of admission and after 6 weeks of treatment with risperidone. Methods: Plasma BDNF and β-NGF levels were measured in 36 schizophrenia patients and 36 healthy controls. All the patients underwent 6 weeks of treatment with risperidone. The severity of schizophrenia and response to treatment were assessed with the positive and negative syndrome scale (PANSS). We compared plasma BDNF and β-NGF levels among much-improved (n = 13, 36.1%, ≥50% PANSS score reduction), minimal-improved (n = 15, 41.7%, ≥25% and <50% PANSS score reduction) and nonresponse patients (n = 8, 22.2%, <25% PANSS score reduction). Results: At baseline, plasma BDNF had no significant difference between schizophrenia patients and controls, but β-NGF levels were significantly lower in schizophrenia patients than controls (p = 0.037). Plasma BDNF and β-NGF in all schizophrenia patients had no significant changes between pre- and posttreatment. Baseline BDNF levels were significantly lower in nonresponse patients than others (p = 0.038). After treatment, much-improved patients had significantly higher plasma BDNF than nonresponse patients (p = 0.023). However, β-NGF levels had no significant differences between them. Conclusions: Our data suggest that higher plasma BDNF levels might be associated with better response to risperidone treatment, while plasma β-NGF levels might have no effect on the clinical response in schizophrenia patients.