The relationship between suicidal behavior and hematological inflammatory parameters: a retrospective cohort study

This study investigated the relationship between hematological inflammatory parameters and suicidal behavior by examining their levels before and at the time of referral, exploring their potential use as early indicators in assessing suicide risk.

Our sample consisted of 454 individuals who visited the emergency department due to suicidal behavior and 451 control individuals of similar age and gender. Routine hematological parameters(neutrophils, monocytes, lymphocytes, platelets) and indices calculated from these values, such as NLR, MLR, PLR, SII, and SIRI, were evaluated both in the period prior to the year of presentation and at the time of presentation. Clinical characteristics and inflammatory parameters were analyzed for suicide attempts and completed suicides. Logistic regression analyses were performed to assess between-group differences, individual changes over time, and factors predicting suicidal behavior.

In our study, inflammatory parameters were significantly elevated in the suicide behavior group(p<0.001). MLR and SIRI levels showed the strongest association with suicide attempts. Logistic regression analysis revealed that high MLR levels prior to admission increased the risk of suicide attempts by 25 times(OR = 25.2), while high monocyte levels at admission increased this risk by 8 times(OR = 7.7). Suicide-related mortality was associated with male gender, the presence of additional physical illnesses, and the absence of psychiatric evaluation. High MLR(OR = 12.202, p=0.007) and monocyte(OR = 13.113, p< 0.001) levels at the time of admission significantly predicted mortality.

Our findings support the presence of chronic low-grade inflammation in suicidal behavior and indicate that these parameters have the potential to be used as accessible and low-cost biomarkers in the assessment of suicide risk.