Longitudinal study of inflammation and relapse in schizophrenia

Introduction: The clinical course of schizophrenia is often characterized by recurrent relapses. Blood inflammatory markers are altered in acute psychosis, and may be state markers for illness relapse in schizophrenia. Few studies have investigated longitudinal, intra-individual changes in inflammatory markers as a predictor of relapse. In the present study, we explored this association in a relapse prevention trial in patients with schizophrenia. Methods: We analyzed blood inflammatory markers in 200 subjects, with a mean 11 samples per subject, during the 30 month Preventing Relapse in schizophrenia: Oral Antipsychotics Compared to Injectable: eValuating Efficacy (PROACTIVE) trial. Associations between longitudinal changes in inflammatory markers and relapse were analyzed using a within-subjects design. Results: 70 (35 %) of subjects relapsed during the study period. There were no significant differences in mean inflammatory marker levels based on relapse status (yes/no). Baseline levels of inflammatory markers did not predict incident relapse. Among subjects who relapsed, there was a significant decrease in mean blood IL-6 (n = 38, p = 0.019) and IFN-γ (n = 44, p = 0.012) levels from the visit before the relapse to the visit after relapse. Conclusion: Although there was some evidence for inflammation as a potential state marker for acute psychosis, we did not find significant evidence for its utility as a relapse-predictive marker.