Oxidative Stress Biomarkers in Bipolar Disorder with Suicidal Behavior: A Systematic Review

Abstract

Oxidative stress has been implicated in suicidal behavior and bipolar disorder (BD), respectively. However, the role of oxidative
stress as a biomarker of suicidal behavior in BD remains inconclusive. This systematic review aims to determine the association
between oxidative stress biomarkers and suicidal behavior among BD patients. All human studies from Scopus and Ovid Medline
up until August 2017 on suicidal behavior, BD, and oxidative stress biomarkers were included according to Preferred Reporting
Items for Systematic Reviews and Meta-Analyses guidelines. A total of five studies met the eligibility criteria, of which 4 were
case–control studies. Three studies identified at least one biomarker with significant association between suicidal acts and oxidative
stress biomarkers (i.e., increased lipid peroxidation and NOS3 rs1799983 TT genotype) in previous suicide attempt and increased
deoxyribonucleic acid damage in suicide among sample populations with BD patients. No study reported conclusive associations
between Ala‑9 Val manganese superoxide dismutase or Pro 197 Leu glutathione peroxidase gene polymorphisms; or levels of nitric
oxide metabolites, plasma total antioxidant potential, and malondialdehyde with suicidal acts among BD patients. Based on this
systematic review, there is limited evidence of any association of the association between oxidative stress biomarkers and suicidal
acts in BD patients. Definitive conclusions could not be ascertained due to lack of homogenous properly controlled and adequately
powered studies. Future systematically well-designed and larger, prospective studies are warranted to clarify the role of oxidative
stress pathways in the pathophysiology of suicidal behavior in BD.