Association of plasma IL-33 levels with aggression in schizophrenia: A clinical study

Aggression in schizophrenia (SCZ) poses a serious risk to others and complicates treatment. Inflammation has been confirmed to be associated with aggression in SCZ, but specific biomarkers remain unidentified. This study aimed to measure plasma interleukin-33 (IL-33) levels and explore their association with aggression in SCZ for the first time. The enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of IL-33 in SCZ with aggression (SCZ-Ag, n = 31) and non-aggression (NSCZ-Ag, n = 32), and healthy controls (HCs, n = 26). Aggression was measured using the Modified Overt Aggression Scale (MOAS), and clinical symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). The results showed that the plasma IL-33 levels were elevated in SCZ-Ag compared with NSCZ-Ag and HCs, with no significant difference between NSCZ-Ag and HCs. In the patient group, partial correlation analysis indicated a positive correlation between IL-33 levels and PANSS total scores, positive symptom subscores, and MOAS total scores. Regression analysis showed that a higher likelihood of aggression in SCZ was associated with elevated plasma IL-33 levels (OR = 1.075, 95 % CI: 1.023-1.129). ROC curve analysis showed that IL-33 (AUC = 0.713, 95 % CI: 0.582-0.844) demonstrated moderate performance in distinguishing SCZ-Ag from NSCZ-Ag. These findings suggest that elevated plasma IL-33 levels are a potential risk factor for aggression in patients with SCZ and are implicated in the clinical symptoms of patients. Increased plasma IL-33 levels may serve as a potential marker for aggression in SCZ. These findings require further validation in future studies.