Vitamin D and Neurotrophin Levels and Their Impact on the Symptoms of Schizophrenia

Abstract

Introduction: Vitamin D is involved in brain development and functioning, as well as in regulation of neurotrophic factors. Changes in the expression of those factors are possibly responsible for morphologic abnormalities and symptoms in patients suffering from schizophrenia. Objective: The main goal of this research was to investigate the interrelationship between vitamin D, nerve growth factors (NGF, brain-derived neurotrophic factor [BDNF], and neuregulin-1 [NRG1]), and schizophrenia symptom domains. Methods: This research included 97 inpatients diagnosed with schizophrenia. Schizophrenia symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). Blood samples were taken in order to analyze concentrations of vitamin D, BDNF, NRG1, and NGF growth factors. The obtained results were used in a multiple regression analysis. Results: The vitamin D concentration positively affected the concentration of NRG1 (F = 8.583, p = 0.005) but not the concentration of other investigated growth factors (BDNF and NGF). The clinical characteristics and symptom domains of schizophrenia seemed to be unaffected by the concentrations of vitamin D, BDNF, and NGF, while the NRG1 concentration significantly affected positive symptom domains of schizophrenia (F = 4.927, p = 0.030). Conclusion: The vitamin D concentration positively affected NRG1 levels but not schizophrenia symptomatology as measured by PANSS. The as­sociation between the two could be intermediated via NRG1.