The Relationship between Metabolic Syndrome, BDNF, and Vitamin D in Patients with Schizophrenia

The objective of this study is to investigate the relationship between anthropometric (BMI and waist circumference), metabolic (glucose, insulin, insulin resistance, HbA1c, and lipid profile), psychopathologic (Positive and Negative Syndrome Scale, PANSS) parameters with vitamin D and serum brainderived neurotrophic factor (BDNF) levels in patients with schizophrenia. The study population consisted of 54 healthy control subjects, and 64 volunteer patients, monitored in the psychiatry outpatient clinics of Antalya Education and Research Hospital. Serum glucose, HDL, LDL, triglyceride, total cholesterol levels (spectrophotometric method), HbA1c (HPLC method), insulin, and vitamin 25(OH) D (chemiluminescence method), with HOMA-IR (numerical calculation), and serum BDNF levels (sandwich ELISA, enzymelinked immunosorbent assay) were quantitatively evaluated using respective analytical methods indicated in parentheses. Twenty-seven (42.18%) of 64 schizophrenia patients were diagnosed with MetS. In schizophrenia patients diagnosed with metabolic syndrome (MetS), PANSS-negative and -positive symptom scores were significantly higher, while serum BDNF levels were significantly lower. In patients with schizophrenia, significantly negative correlations were detected between PANSS-negative and -positive symptom scores, and BDNF (p < 0.001 and p < 0.001, respectively), and also between PANSS-negative symptom score and vitamin D (p = 0.022). Lower serum BDNF levels may be related to increases in the possible development of MetS and psychotic symptoms. Decrease in vitamin D levels in schizophrenia patients may be associated with an increase in PANSS-negative symptom scores. In schizophrenia patients with MetS, psychotic symptoms may be more severe.