Clozapine therapy raises serum concentrations of high sensitive C-reactive protein in schizophrenic patients.

Eight schizophrenic inpatients without manifest comorbidity were longitudinally studied. The aim was to find whether clozapine, the prototype of atypical antipsychotic drugs, altered their serum concentrations of high sensitive C-reactive protein (hsCRP), an inflammatory marker of high clinical importance. Following first-time therapy with clozapine, predominantly as the sole antipsychotic for 8 weeks, hsCRP profiles increased subclinically by 600%. This rise, and the Spearman correlation between hsCRP values and corresponding leukocyte counts, was statistically significant. A one-time cross-section investigation of 25 long-term clozapine patients and 25 patient controls did not show an elevation of hsCRP under clozapine after 1 year and more. It is assumed that the clozapine-evoked increase of hsCRP is part of a transient acute-phase response. The underlying inflammatory process needs clarification.