The Relationship between Baseline Neutrophils Counts and Response to 12 Weeks of Antipsychotics in First-Episode Psychosis

Multiple pathways of immune system activation have been implicated in psychosis. Elevated neutrophils and neutrophil-lymphocyte ratio (NLR) as a marker of inflammatory response have been well studied in case-control studies of schizophrenia and first-episode psychosis. However, only one prior study has examined the potential of baseline neutrophil counts or NLR to predict treatment outcomes in first-episode psychosis. We examined whether absolute and relative neutrophil counts at baseline could predict positive symptom improvement in a cohort of 85 patients with first-episode psychosis who received up to 12 weeks of antipsychotic treatment. We used logistic regression with treatment response (defined as the absence of psychotic-level positive symptoms) as the binary outcome of interest and absolute/relative neutrophil measures as the predictor variables of interest, controlling for the following covariates: smoking status, BMI, antipsychotic naïve status, race, and sex. We found that higher NLR (OR 0.53, 95% CI 0.28–0.96, p = 0.041) and neutrophil relative count (OR 0.91, 95% CI 0.84–0.98, p = 0.013), but not absolute counts (OR 0.86, 95% CI 0.6–1.23, p = 0.39), were significantly associated with decreased likelihood of treatment response. We have thus demonstrated that baseline NLR is inversely correlated with antipsychotic treatment response in the acute phase of treatment for patients with first-episode psychosis. Although effect sizes were too small for individual-level prediction, our findings suggest a potential role for inflammatory markers in predicting treatment response. Further studies are needed to identify more specific mechanisms underlying this association.