W214 - Immune-related Biomarkers and Suicidal Behaviors: A Meta-analysis

Elizabeth Ballard – National Institutes of Health; Federico Daray – University of Buenos Aires; Hanga Hanga Galfalvy – Columbia University; Liat Liat Itzhaky – Geha Mental Health Center of the Clalit HMO; J Mann – Columbia University; Mina Rizk – Columbia University; Aviv Segev – Sackler School of Medicine; Assaf Shelef – Tel Aviv University; Oren Tene – Tel Aviv Medical Center; Gil Zalsman – Tel Aviv University

Abstract Text: Biomarkers that can differentiate between psychiatric disorders with and without a history of suicidal behavior from each other and from healthy volunteers may explain part of the pathogenesis of suicidal behavior and aid its prevention. We conducted the hitherto largest meta-analysis comparing immune biomarkers between subjects with and without suicidal behaviors. The study protocol was registered with PROSPERO, CRD42020212841. Two independent reviewers screened the publications, extracted data and evaluated study quality. Standardized mean differences (SMD) were calculated for all comparisons and pooled with random-effects models. Heterogeneity between studies was assessed with the I2 statistic and publication bias was evaluated by funnel plots. Data were based on twenty-four studies including 2042 persons with suicidal behaviors and 4471 comparison subjects, and four immune-related biomarkers (CRP, IL-6, TNF-α and IL-1β). Suicidal behavior was associated with higher CRP blood levels compared with: healthy controls (SMD [95%CI] = 1.33[0.67-2.00]); patients with depression alone (SMD [95%CI] = 0.67[0.08-1.26]); and patients with any psychiatric disorders (SMD [95%CI] = 0.49[0.25-0.73]). IL-6 blood level was higher in patients with suicidal behaviors compared with healthy controls (SMD [95%CI] = 1.43[0.49-2.38]). IL-1ß blood level was lower in depression with suicidal behaviors compared with depression without suicidal behaviors (SMD [95%CI] = -0.34[-0.67 to -0.01]). These results implicate the immune system and inflammatory response in suicidal behavior independent of a relationship to major psychiatric disorders. Future studies are needed to determine the cause-and-effect relationship of these immune system biomarkers with risk of suicidal