IMMUNE MARKERS AS PREDICTORS OF SUICIDE ATTEMPTS IN PERSONS WITH MAJOR DEPRESSION AFTER HOSPITAL DISCHARGE: A PROSPECTIVE STUDY

Abstract Background More than 40,000 people in the US die by suicide each year, the majority of whom have a major mood disorder. We have previously found in cross-sectional studies that individuals with mood disorders who have undergone a recent attempt have altered immune status.1, 2 The immune factors which predict future suicide attempts have not been previously defined. Aims and Objectives The aim of this study is to determine the predictive value of clinical and serological markers for suicide attempts during the high-risk six-month period following hospital discharge in persons with acute major depression. Methods We assessed adults with major depressive disorder who were hospitalized for an acute depressive episode. Some of these individuals had a suicide attempt in the previous month while the others had no lifetime suicide attempt history. At baseline, persons were assessed on the Columbia Suicide Severity Rating Scale and clinical measures of depression severity, adverse childhood events, impulsiveness, stress, and comorbid medical conditions. Each participant had a blood sample drawn from which antibodies to infections agents, cytokines and chemokines, and other markers of inflammation were measured. Patients were assessed monthly for 6 months. The primary outcome was a suicide attempt in the follow-up period. Regression analyses were performed on outcomes with baseline variables; principal components analysis was performed on serological variables, and Cox proportional hazards were calculated on suicide attempts adjusting for age, race, sex, and other covariates. Results The sample consisted of 100 individuals hospitalized for major depression, 69 with a recent suicide attempt, and 31 with no suicide attempt history; average age 31.9 ±11.7 years, female sex 66 (66%), 58 (58%) White race. A total of 91 persons had a follow-up visit of whom 14 (15%) had a suicide attempt in the 6-month follow-up period, all from the group with a recent suicide attempt at baseline. Significant baseline predictors of a repeat suicide attempt included having an immune or autoimmune condition (HR 8.32, 95% CI 2.52, 27.46, p<.0001); elevation of a combined serological marker comprised of increased levels of the cytokines, TNF-alpha and IL-1β, and decreased IgG antibodies to Epstein Barr Virus; Viral Capsid Antigen (HR 3.57, 95% CI 1.09, 11.8, p=.04). Persons who had both an immune or autoimmune disorder at baseline and elevation of the combined serological marker had an increased risk of a repeat suicide attempt with a hazard ratio of 2.01 (95% CI 1.21, 3.32, p=.007). Repeat suicide attempts were also associated with stress related to a change in work hours (p=.001) and eating habits (p=.02), and symptoms of restlessness (p=.03) and agitation (p=.007). Discussion and Conclusions Persons with acute depression and immunological abnormalities represent a high-risk group for repeat suicide attempts. Future studies should address the question of whether suicide attempts can be predicted using measures of immune functioning and may be prevented by the administration of immunomodulatory agents. References 1.Dickerson et al. Suicide attempts and markers of immune response in individuals with serious mental illness. J Psychiatr Res. 2017 Apr;87:37-43. 2.Dickerson et al. The association between immune markers and recent suicide attempts in patients with serious mental illness: A pilot study. Psychiatry Res. 2017 Sep;255:8-12.