Relationship between the levels of chitinase-3 like protein 1 (YKL-40), brain derived neurotrophic factor (BDNF), glial fibrilar acidic protein (GFAP), interleukin 1 (IL-1), tumor necrosis factor (TNF-alfa) and insight in patients with schizophrenia

In schizophrenia, which causes severe disability in the community, patients with lower levels of insight have a worse prognosis. It is known that inflammatory processes may have a role in the etiology of insight. The development of prognostic biomarkers is an unmet need to facilitate diagnosis, prognosis, and treatment follow-up, improve quality of life, and reduce healthcare costs worldwide in patients with schizophrenia. In this study, it was aimed to compare the plasma levels of chitinase-3-like protein 1 (YKL-40), Brain-Derived Neurotrophic Factor (BDNF), Glial Fibrillary Acidic Protein (GFAP), Interleukin-1 (IL-1) and Tumor Necrosis Factor-alpha (TNF- α) in patients with schizophrenia with healthy controls and to determine their relationship with insight. Materials and Methods: In this study, 45 patients aged 18-65 years who applied to the Dicle University Medical Faculty Hospital Psychiatry Outpatient Clinic between 15.11.2022 and 30.06.2023 and diagnosed with schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition and a control group of 45 healthy volunteers with similar sociodemographic characteristics were included. Sociodemographic data form and Positive and Negative Syndrome Scale (PANSS), Schedule for assessing the three components of insight, Schizophrenia Cognition Rating Scale (SCoRS), Depression Anxiety Stress Scale (DASS-21), Clinical Global Imaging Scale Severity subscale (CGI-S) were applied after the participants signed the informed consent form. Results: In our study, BDNF, YKL-40, TNF-α, GFAP, and IL-1 levels were found to be significantly lower in the patient group compared to the control group. A positive correlation was detected between TNF-α, YKL-40, BDNF, GFAP, and IL-1 in the patient group, but no correlation was detected with PANSS, CGI-S, DASS 21, SCoRS, Schedule for assessing the three components of insight scale scores. Conclusion: In our study, BDNF, YKL-40, TNF-α, GFAP, and IL-1 levels were found to be significantly lower in the patient group compared to the control group, and no significant correlation was found between inflammatory marker levels and insight scale scores in the patient group. In our literature review, it was noticed that although there are other studies on blood biochemical marker levels in schizophrenia, there are few studies examining its relationship with insight. Our study is important because it is the first study in the literature to evaluate the relationship between inflammatory marker levels such as YKL-40 and insight in schizophrenia patients. Keywords: Schizophrenia, YKL-40, BDNF, GFAP, IL-1, TNF-alpha, Insight