Complete blood count inflammatory markers in treatment-resistant schizophrenia: Evidence of association between treatment responsiveness and levels of inflammation.

Accumulating evidence suggests that the variable response to antipsychotic treatment in schizophrenia reflects distinct biological subtypes. The pathophysiology of schizophrenia is associated with alteration in the immune system which can be measured with complete blood count (CBC) markers of systemic inflammation, including the neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR). While previous research suggested a decrease in CBC inflammatory markers following treatment, it is unknown if treatment or response to treatment is associated with CBC markers in treatment-resistant schizophrenia. Here, we retrospectively analyzed the CBC at admission and discharge in schizophrenia inpatients classified as treatment-responsive, treatment-resistant, and ultra-treatment-resistant. Despite similar NLR at admission, the subtypes manifested different changes in NLR during treatment resulting in significant differences at discharge. Only the treatment-responsive group presented a significant decrease in inflammatory markers after treatment. Additionally, we found that the responsive group had a higher PLR at admission and was the only subgroup to demonstrate a significant reduction following treatment. In sum, our results support the idea that persistent inflammation is a biological trait marker of treatment resistance in schizophrenia.