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SUICIDAL IDEATION IS ASSOCIATED WITH ELEVATED INFLAMMATION IN PATIENTS WITH MAJOR DEPRESSIVE DISORDER

Authors

  • Aoife O'Donovan Ph.D.,

    Corresponding author
    1. Department of Psychiatry, Psychotherapy and Mental Health Research, St. Vincent's University Hospital, Dublin, Ireland
    2. Stress and Health Research Program, San Francisco Veteran's Affairs Medical Center, San Francisco, California
    3. Department of Psychiatry, University of California, San Francisco, California
    • School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland
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  • Gavin Rush M.B.,

    1. St. Patrick's University Hospital, Dublin, Ireland
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  • Gerard Hoatam M.S.,

    1. School of Medicine, Creighton University, Omaha, Nebraska
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  • Brian M. Hughes Ph.D.,

    1. Department of Psychology, National University of Ireland, Galway, Ireland
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  • AnnMaria McCrohan Ph.D.,

    1. Department of Psychiatry, Psychotherapy and Mental Health Research, St. Vincent's University Hospital, Dublin, Ireland
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  • Cecily Kelleher Ph.D.,

    1. School of Public Health, Physiotherapy & Population Science, University College Dublin, Dublin, Ireland
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  • Cliona O'Farrelly Ph.D.,

    1. School of Biochemistry and Immunology, Trinity College, Dublin, Ireland
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  • Kevin M. Malone M.D.

    1. School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland
    2. Department of Psychiatry, Psychotherapy and Mental Health Research, St. Vincent's University Hospital, Dublin, Ireland
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Correspondence to: Aoife O'Donovan, Department of Psychiatry, University of California, San Francisco 3333 California Street, Suite 465, San Francisco, CA 94143-0848. E-mail: aoife.odonovan@ucsf.edu

Abstract

Background

Patients with major depressive disorder (MDD) who attempt or complete suicide have elevated inflammation compared to nonsuicidal patients with MDD. However, greater severity of depression and the medical lethality of suicide attempts could account for such elevated inflammation in suicide attempters and suicide completers.

Methods

To clarify, we measured inflammatory markers in patients with MDD with and without high levels of suicidal ideation and in nondepressed controls (N = 124). Levels of suicidal ideation, depression severity, and recent suicide attempts were assessed by structured clinical interviews. A composite score including the inflammatory markers tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), and C-reactive protein (CRP) was used as an inflammatory index. Analysis of covariance models were used to assess group differences with adjustments for age and gender.

Results

Patients with MDD and high suicidal ideation had significantly higher inflammatory index scores than both controls, F(1,53) = 18.08, partial η2 = .25, P < .001, and patients with MDD and lower suicidal ideation F(1,44) = 7.59, partial η2 = .15, P = .009. In contrast, patients with lower suicidal ideation were not significantly different from controls on the inflammatory index, F(1,63) = .52, partial η2 = .01, P = .47. Follow-up analyses indicated that differences between patients with MDD and high versus lower suicidal ideation were independent of depression severity and recent suicide attempts.

Conclusions

Suicidal ideation may be uniquely associated with inflammation in depressed patients.

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