Evaluation of Simple Markers of Inflammation and Systemic Immune Inflammation Index in Schizophrenia, Bipolar Disorder Patients and Healthy Controls.

Objective: Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), mean platelet volume (MPV), and systemic immune inflammation index (SII) are recently used as indicators of inflammation. NLR, PLR, MLR, and MPV have been evaluated in many studies in patients with schizophrenia and bipolar disorder. However, there are no studies investigating SII. This study aims to evaluate NLR, PLR, MLR, MPV and SII values and complete blood count elements in patients hospitalized with diagnoses of the schizophrenia with psychotic episode and bipolar disorder with manic episode by comparing them with the control group.

Method: A total of 149 patients who were hospitalized with the diagnoses of the schizophrenia with psychotic episode and bipolar disorder with manic episode and who met the inclusion criteria were included in our study where the control group was composed of 66 healthy individuals. White blood cell (WBC), neutrophil, lymphocyte, platelet, and monocyte counts were obtained retrospectively from complete blood counts at the time of admission, based on which NLR, PLR, MLR, and SII were calculated.

Results: In this study, higher NLR, PLR, and SII values and lower MPV and lymphocyte counts were observed in schizophrenia patients compared to the control group. NLR, PLR, and SII values and neutrophil counts were higher in patients with bipolar disorder compared to the control group. Lower MPV values were found in patients with schizophrenia compared to patients with bipolar disorder.

Conclusion: Simple inflammatory and SII values in our study indicate the presence of low-grade systemic inflammation in schizophrenia and bipolar disorder.