Suicides and suicidal behaviors are very important causes of mortality and morbidity and have become a serious global problem. More than 800,000 people die from suicide every year. Previous researches have established that lipids play an important role in the pathogenesis of suicide. Moreover, lipid levels might be a biological marker of suicide. A lot of researchers have tried to identify biological markers that might be related to depressive disorder, bipolar disorder or schizophrenia and suicidal behavior. It was also important to consider the usefulness of an additional tool for prevention actions. Metabolic deregulation, particularly low total cholesterol and low-density lipoproteins-cholesterol levels may cause higher suicide risk in patients with these psychiatric disorders.

Background: This study aimed to evaluate oxidative stress parameters in individuals with depression and schizophrenia, considering gender differences, and manifesting suicidal behavior, encompassing thoughts without a tendency to be realized, thoughts with a tendency to be realized, and suicide attempts.Methods: From among the patients from Department of Psychiatry 120 individuals were selected who met the inclusion criteria and did not meet the exclusion criteria for the study. In the initial phase of the project, patients eligible for the study underwent the M.I.N.I 7.0.2 questionnaire (Mini International Neuropsychiatric Interview). Subsequently, in the second phase of the research, venous blood samples were collected from the patients for the purpose of conducting biochemical assessments, focusing on oxidative stress parameters.Results: The obtained results suggest that redox biomarkers, namely TOS (total oxidation state) and OSI (TOS/TAC ratio), in the blood plasma of women increase in tandem with the severity of suicidal behavior. No notable alterations in SOD (Cu-Zn-superoxide dismutase), GPx (glutathione peroxidase), and GSH (reduced glutathione) concentrations and activity were noted between groups exhibiting suicidal behavior. The observed variations in the concentrations and activity of antioxidant parameters were significant solely in comparison to the control group.Conclusions: Redox biomarkers TOS and OSI could prove valuable in diagnosing women at a genuine risk of committing suicide. On the other hand, antioxidant parameters – SOD, GPx, and GSH may be instrumental in identifying patients with suicidal behaviors, without specifying their intensity.