Elevated neutrophil to lymphocyte ratio in non-affective psychotic adolescent inpatients: Evidence for early association between inflammation and psychosis.

Accumulating data suggest an association between inflammation and schizophrenia and related psychosis. While several studies have established this immune-psychosis association in adult schizophrenia patients, there is very limited data associating inflammation with acute psychosis in children and adolescents. The ratio between neutrophils and lymphocyte, computed from routine blood counts, has been shown to correlate with traditional markers of inflammation, and is therefore considered a proxy-marker for inflammation. Here we report elevated neutrophil to lymphocyte ratio and total leukocyte count in psychotic adolescent inpatients (n = 81, mean age 14.7 years, 52% males) compared to non-psychotic adolescent inpatient (n = 285, mean age 15.9 years, 58% males), in a population of adolescent inpatients with no affective symptomatology. The elevated neutrophil to lymphocyte ratio remained significant after controlling for confounders such as age, BMI, smoking and antipsychotic medication. In a subset of psychotic adolescent inpatients (n = 20, mean duration between blood test 157 days), we found significant decrease in neutrophil to lymphocyte ratio at clinical remission compared with the acute psychotic state. The results suggest that psychosis is associated with peripheral markers of inflammation early in the course of psychiatric pathology, and that inflammation may represent a state that accompanies psychosis and decreases during clinical remission.