Increased Interleukin 18 Activity in Adolescents With Early-Onset Psychosis Is Associated With Cortisol and Depressive Symptoms
AuthorWedervang-Resell, Kirsten; Friis, Svein; Lonning, Vera Louise Hiorth; Smelror, Runar; Johannessen, Cecilie Haggag; Reponen, Elina Johanna; Lyngstad, Siv Hege; Lekva, Tove; Aukrust, Pål; Ueland, Thor; Andreassen, Ole Andreas; Agartz, Ingrid; Myhre, Anne Margrethe
Method - We measured serum IL-18, IL-18 binding protein (IL-18BP), IL-18 receptor accessory protein (IL-18RAP), IL-18 receptor 1 (IL-18R1) and cortisol, and calculated the IL-18/IL-18BP ratio in patients (n = 31) and HC (n = 60). Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale and depressive symptoms by the Mood and Feelings Questionnaire-Child version (MFQ-C). Bivariate correlation analysis was used to explore relationships between IL-18/IL-18BP ratio and cortisol, depression and other clinical characteristics. Hierarchical multiple linear regression analysis was used to assess their individual contributions to the variance of the IL-18/IL-18BP ratio.
Results - Patients had significantly higher IL-18 levels and IL-18/IL-18BP ratios than HC, but similar IL-18BP, IL-18RAP and IL-18R1. Both cortisol (R2 change = 0.05) and the MFQ-C score (R2 change = 0.09) contributed significantly to the variance in IL-18/IL-18BP ratios after controlling for confounders.
Conclusion - We found increased IL-18 system activity in adolescents with EOP. Cortisol and depressive symptoms each contributed to the variance in the IL-18/IL-18BP ratio. Our findings support activation of inflammatory pathways in adolescent psychosis and suggest interactions between stress, inflammation and depressive symptoms in EOP.