Meta-Analysis of Cytokines and Chemokines in Suicidality: Distinguishing Suicidal Versus Nonsuicidal Patients

Biol Psychiatry. 2015 Jul 1;78(1):28-37. doi: 10.1016/j.biopsych.2014.10.014. Epub 2014 Oct 30.


Background: Major psychiatric disorders are associated with inflammation. Aberrant cytokine and chemokine levels have been associated with psychiatric disorders and suicidal behavior. We performed a meta-analysis of cytokine and chemokine levels in patients with versus without suicidality and patients with suicidality versus healthy controls.

Methods: We identified articles by searching MEDLINE, PsycINFO, and Thomson Reuters Web of Knowledge databases and the reference lists of identified studies.

Results: Study inclusion criteria were met by 18 studies comprising 583 patients with suicidality, 315 patients without suicidality, and 845 healthy control subjects. Levels of interleukin (IL)-1β and IL-6 were significantly increased in blood and postmortem brain samples of patients with suicidality compared with both patients without suicidality and healthy control subjects (p < .05 for each). In vitro IL-2 production by peripheral blood mononuclear cells was significantly decreased in patients with suicidality compared with both patients without suicidality and healthy controls (p < .01 for each). Cerebrospinal fluid levels of IL-8 were significantly decreased in patients with suicidality versus control subjects (p < .05).

Conclusions: We found evidence for aberrant cytokine levels in blood, cerebrospinal fluid, and postmortem brain samples of patients with suicidality. Levels of IL-1β and IL-6 were most robustly associated with suicidality, and these cytokines may help distinguish suicidal from nonsuicidal patients. Rigorously designed longitudinal studies are needed to evaluate these associations further.

Keywords: Chemokines; Cytokines; Depression; Inflammation; Meta-analysis; Suicide.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Brain / metabolism
  • Chemokines / blood*
  • Chemokines / cerebrospinal fluid*
  • Cytokines / blood*
  • Cytokines / cerebrospinal fluid*
  • Female
  • Humans
  • Inflammation / blood
  • Inflammation / cerebrospinal fluid
  • Interleukin-1beta / blood
  • Interleukin-1beta / cerebrospinal fluid
  • Interleukin-8 / blood
  • Interleukin-8 / cerebrospinal fluid
  • Male
  • Mental Disorders / blood
  • Mental Disorders / cerebrospinal fluid
  • Mental Disorders / complications
  • Middle Aged
  • Receptors, Interleukin-6 / analysis
  • Receptors, Interleukin-6 / blood
  • Suicide*


  • CXCL8 protein, human
  • Chemokines
  • Cytokines
  • IL6R protein, human
  • Interleukin-1beta
  • Interleukin-8
  • Receptors, Interleukin-6