The adipokines leptin, adiponectin, tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) might be associated with metabolic syndrome (MetS) in patients with schizophrenia. In the present study, we attempted to confirm the results of previous reports and assessed their MetS-related correlation with body fat composition and biochemical parameters. We measured in 46 patients with schizophrenia and MetS serum levels of adiponectin insulin, leptin, TNF-α and IL-6 and compared these levels to those of patients with schizophrenia without MetS. The MetS patients had significantly increased leptin levels and leptin/adiponectin ratios, as well as decreased adiponectin levels. Leptin levels correlated with several metabolic parameters, both in patients with and without MetS, including body fat percentage, total fat fold, and body mass index (BMI). Patients without abnormal MetS components had lower levels of leptin and leptin/adiponectin ratios compared with patients who had one or two MetS components. Leptin/adiponectin ratios were higher in patients who had four rather than three MetS components. Multiple regression analysis revealed multiple associations for leptin but only one for adiponectin, TNF-α, and IL-6. Our results support an important pathophysiological role for leptin more than adiponectin in patients with schizophrenia with MetS.

Background: Schizophrenia is a complex mental disorder with a high heritability. Dysfunction of the N-methyl-D-aspartate (NMDA)-type glutamate receptors may be involved in the pathogenesis of schizophrenia. In this study, we examined the contribution of GRIN2A and GRIN2B (Glutamate Ionotropic Receptor NMDA Type Subunit 2A/2B) polymorphisms to the clinical features of schizophrenia, such as the leading symptoms, the type of course, and the age of onset. Methods: A population of 402 Russian patients with schizophrenia from the Siberian region was investigated. Genotyping of seventeen single-nucleotide polymorphisms (SNPs) in GRIN2A and GRIN2B was performed using QuantStudio™ 3D Digital PCR System Life Technologies amplifier using TaqMan Validated SNP Genotyping Assay kits (Applied Biosystems). The results were analyzed using Chi-square and the Fisher’s exact tests. Results: We found an association of GRIN2A rs7206256 and rs11644461 and GRIN2B rs7313149 with the early onset (before the age of 18 years old) schizophrenia. We did not reveal any associations of GRIN2A and GRIN2B polymorphisms with leading (positive vs. negative) symptoms or type of course (continuous vs. episodic) of schizophrenia. Conclusions: In the study, we confirmed the involvement of the GRIN2A and GRIN2B genes in the early onset of schizophrenia in a Russian population of the Siberian region.