Comparison of the anti-inflammatory effect of aripiprazole and risperidone in 75 drug-naïve first episode psychosis individuals: A 3 months randomized study

Introduction: Evidence about the anti-inflammatory properties of antipsychotics has grown. However, no previous studies have compared the immunomodulatory effect of risperidone and aripiprazole.

Objectives: The main aim of the present work is to compare the anti-inflammatory effect of risperidone and aripiprazole on a large array of serum cytokines at 3 months following the onset of treatment.

Methods: This is a prospective, randomized, open-label study. Patients were randomly assigned to risperidone or aripiprazole. From this randomization, 75 patients and 75 healthy volunteers that matched with the selected patients were picked for entry in this study. Serum concentrations of 21 cytokines/chemokines were measured at baseline and 3 months following the initiation of antipsychotic medication.

Results: Those patients who were randomly assigned to risperidone had higher levels of IL-8 (p = 0.000) and MIP-1β (p = 0.007) than healthy volunteers at baseline, whereas no differences were found between patients initially assigned to aripiprazole and healthy volunteers. Three months following the onset of medication several cytokines decreased significantly: IL-8, MIP-1β, Fractalkine, TNF-α, IL-7, IL-13, IL-17α, IL-23, IL-21 (all ps < 0.01). No differences were found in the percentages of change between both treatments. The effect size of the two antipsychotics was similar, except for TNF-α, IL-13, IL-17α and Fractalkine, in which aripiprazole seems to have a greater effect size than risperidone, whereas risperidone seems to have a greater effect size than aripiprazole on MIP-1β.

Conclusions: This is the first study that has compared the immunomodulatory effect of risperidone and aripiprazole, finding that the anti-inflammatory effect of both treatments was similar.