LAUSR

Background Major Depression (MDD), neuroticism and psychological distress have each been associated with an increased risk of several diseases commonly associated with ageing. In the current study, we sought to identify which of these traits was associated with methylation age acceleration, and if any methylation age association with MDD or distress survive correction for neuroticism. Methods We conducted assessments of DNA methylation age in Generation Scotland (N=22,000 individuals), a family and population-based cohort from Scotland. DNA methylation was assessed genome wide using the Illumina EPIC array in 5000 individuals, of whom 500 were also assessed longitudinally. Results Associations were found between methylation age acceleration, MDD and psychological distress. Somewhat contrasting results were found for the Hannum and Horvath epigenetic clocks. Discussion These findings suggest that accelerated biological ageing is associated MDD and psychological distress, and later analyses from this dataset will seek to determine the directional relationship, and specifically whether MDD is leading to ageing acceleration, or whether accelerated ageing is increasing the likelihood to developing MDD.