Immune system dysregulation, increased inflammatory cytokines and suicidal behavior: a systematic review.

Introduction: Suicidal behavior, which is frequently linked to mood disorders, is amajor public health concern associatedwith significant disability and psychosocial impairment worldwide. Inflammatory mediators seem to play a fundamental role in the pathophysiology of bothmood disorders and suicidal behavior. In particular, a specific correlation between abnormally elevated pro-inflammatory cytokines and depression severity has been identified. Objectives: The present systematic review aimed to explore the nature of the association between increased inflammatory cytokines and suicidal behavior. Methods: This is a systematic review of the current literature about the role of pro-inflammatory cytokines in suicidal behavior. Only articles from peer-reviewed journals were selected for inclusion in the present review. Results: The cytokine profile of patients at risk for suicidal behavior significantly differed from that of patients who are not at suicide risk. Importantly, there may be an important imbalance between pro- and anti-inflammatory cytokines in individuals who die by suicide. Most studies reported the link between suicidal behavior and specific pro-inflammatory cytokines such as IL2, IL-6, IL-8, and TNF-a. Differences regarding the inflammatory cytokine profile emerged between subjects with active suicidal ideation and/or history of prior suicide attempts when compared to those without suicidal ideation/attempts. However, the existence of a causal association between suicidal behavior and neuronflammation needs to be further explored. Conclusions: Based on most of the studies included in the present review, neuroinflammation plays a crucial role in the pathophysiology of suicidal behavior. Additional studies should elucidate the molecular mechanisms of the immune activation pathways underlying suicidality. [ABSTRACT FROM AUTHOR]