Low Dose Celecoxib Combined with Clozapine for Treatment of Schizophrenia: A Double Blind Randomized Clinical Trial

Introduction: Higher levels of pro-inflammatory cytokines in schizophrenia have suggested that dysfunctions of the immune system may play a role in this disabling condition. The current study was performed to discover if low dose celecoxib combined with clozapine may improve symptoms of schizophrenia or not. Methods: In a double-blind randomized clinical trial, 40 patients with non- treatment resistance schizophrenia were allocated into two groups. The experimental group received flexible and low dose clozapine plus 200 mg/day of celecoxib for 4 weeks, while the control group received clozapine plus placebo. Experimental and control groups were similar in terms of age, gender, clozapine mean dosage and severity of schizophrenic symptoms at baseline. Main outcomes were severity of schizophrenia symptoms measured by the Positive and Negative Syndrome Scale (PANSS) at baseline followed by the second and fourth weeks. Results: Although both groups experienced significant improvement in all PANSS sub-scales in the second and fourth weeks (P<0.001), the differences between the two groups did not reach significance (P>0.05). Conclusion: Our findings did not support the findings of prior studies that report a significant effect for celecoxib combined with atypical antipsychotics. Such inconsistency may be due to statistical power, drug interactions between clozapine and celecoxib, and the low dose of celecoxib used in this study. Future research is needed on the role of anti-inflammatory medications as adds-on treatments for schizophrenia.