Blood viscosity and inflammatory indices in treatment-resistant schizophrenia: A retrospective cross-sectional study

Objective: Alterations in blood flow and inflammation may be associated with the treatment response of psychotic disorders. However, changes in blood viscosity in patients with treatment-resistant schizophrenia (TRS) have yet to be studied. We examined whether blood viscosity and systemic inflammatory status varied between patients with TRS, remitted schizophrenia, and healthy subjects. Method: Forty patients with TRS, 40 remitted schizophrenia patients, and 43 age-and gender-matched healthy controls were enrolled in this retrospective file review study. Whole blood viscosity (WBV) was calculated according to de Simone’s formula at low and high shear rates (LSR and HSR, respectively). Complete blood count (CBC) markers of inflammation were recorded through screening data at admission. Results: In patients with TRS, WBV at both LSR and HSR was significantly decreased, whereas all CBC markers of inflammation were significantly increased compared to controls. Remitted patients had significantly decreased WBV at HSR than controls. There was no significant correlation between blood viscosity and CBC markers in patients. According to the regression models, the systemic immune-inflammation index (β=0.578) and monocyte-to-lymphocyte ratio (β=1.844) were significantly associated with WBV at LSR in multivariate analyses, whereas the Positive and Negative Syndrome Scale (PANSS) Positive subscale (β=-0.330) was significantly associated with WBV at HSR in univariate analyses in the patient sample. Conclusion: TRS, associated with decreased blood viscosity and increased inflammatory status, may not fully explain such a relationship. Prospective studies would help establish the extent to which hemorheological and inflammatory characteristics reflect the pathophysiological process underlying treatment responsiveness as well as cardiovascular morbidity.