Investigation of the relationship between hemogram parameters and procalcitonin levels in patients with psychiatric diseases

Introduction
This study aimed to evaluate the relationship between the hemogram parameters and the levels of procalcitonin, serum C-reactive protein, and inflammation in inpatients with psychiatric disorders.

Material and methods
The study population consisted of 549 inpatients treated between January 2018 and December 2020. Data were obtained retrospectively from computer records and inpatient files. Only the first hospitalization of each patient was evaluated, and 199 patients were included in the study. The researchers examined the parameters including platelet activation, neutrophil lymphocyte ratio, monocyte lymphocyte ratio, platelet count, mean platelet volume, platelet distribution width, platelet lymphocyte ratio, and procalcitonin levels in patients and compared them with findings obtained from a control group.

Results
Increased levels of C-reactive protein and decreased levels of platelets were observed in patients with schizophrenia, bipolar disorder, depressive disorder, and anxiety disorder. Increased platelet distribution width, platelet lymphocyte ratio, and neutrophil lymphocyte ratio were observed in patients with schizophrenia. The patients with bipolar disorder had increased mean platelet volume while patients with depressive disorder had an increased monocyte lymphocyte ratio. Procalcitonin levels increased in patients with anxiety disorder and depressive disorder.

Conclusions
Platelet activity can be an important criterion to investigate the etiopathogenesis underlying the inflammatory process in schizophrenia, bipolar disorder, depressive disorder, and anxiety disorders. To our knowledge, this is the first study to describe a positive correlation between increased monocyte lymphocyte ratio and procalcitonin levels in depressive disorder, and a positive correlation between increased procalcitonin levels and anxiety disorder and depressive disorder.