Single-Nucleotide Polymorphisms in Interleukin 6 (IL-6) Gene Are Associated with Suicide Behavior in an Iranian Population.

Previous association studies have demonstrated the association between immune regulatory genes and suicide behavior. Among these genes are those coding for cytokines. In the present study, we genotyped two interleukin 6 (IL-6) variants (rs2069845 and rs1800795) in 320 suicide attempters, 236 suicide completers, and 341 individuals without any history of psychiatric disorders or suicide ideation. The rs2069845 was not associated with suicide behavior. The rs1800795 C allele was significantly more common among suicide completers compared with suicide attempters (OR (95% CI) = 1.33 (1.04-1.71)), adjusted P = 0.04). Besides, the rs1800795 was associated with the lethality of suicide attempt in recessive model (adjusted P value = 0.01). Consequently, the present study supports the role of IL-6 in suicide behavior and warrants further researches to confirm its effect and explain the underlying mechanism.