The role of global DNA methylation and epigenetic aging in the suicidality of patients with schizophrenia

Suicide is a leading cause of death among individuals with schizophrenia. Studies suggest that suicide attempters show increased DNA methylation and shorter telomere lengths, both linked to accelerated biological aging. Recently, DNA methylation has been used to estimate epigenetic aging and telomere length, the former of which serves as the most accurate measure of biological aging. In this study, we investigated whether patients with schizophrenia spectrum disorder (SSD) and a history of suicide attempts show greater biological aging than non-attempters. Epigenetic aging and telomere length were assessed in DNA samples extracted from white blood cells of 60 SSD patients using methylation-based epigenetic clocks. Suicide attempters showed higher epigenetic age acceleration (EAA) on the Hannum DNAm Age clock compared to non-attempters, although other clocks displayed similar trends. However, this was no longer significant after correcting for multiple comparisons (p = 0.0356, pFDR = 0.2136). These findings suggest that accelerated epigenetic aging may be associated with suicide risk in schizophrenia. Finally, investigating the factors underlying this association would improve our understanding of suicidality and the ability to develop effective prevention measures.