Association between telomere length and psychiatric disorders: a bidirectional Mendelian randomization study

Observational studies have suggested that shorter telomere length (TL) may be a risk factor for psychiatric disorders. However, whether this association underlie causal effects remains unknown. This study aims to investigate the potential association between TL and psychiatric disorders by conducting a bidirectional Mendelian randomization (MR) study. Summary statistics for TL were obtained from the UK Biobank (n = 472,174), while summary statistics for ten psychiatric disorders were acquired from the Psychiatric Genomics Consortium (PGC). The inverse-variance weighted (IVW) method was used as primary analysis, with the MR-Egger, weighted median, MR-PRESSO, simple mode, and weighted mode approaches were utilized as sensitivity analyses. Our findings indicated a potential association between genetic predisposition to attention deficit hyperactivity disorder (ADHD) and shortened TL (Beta = - 0.039, SE = 0.011, P = 4.00E-04). Additionally, posttraumatic stress disorder (PTSD) may be was potentially associated with TL (Beta = - 0.014, SE = 0.006, P = 0.019). Our findings suggest a potential correlation between ADHD and TL, yet no significant association exists between TL and other psychiatric disorders. Nevertheless, considering the small effect size and the fact that it might have limited practical clinical significance, TL may not function as a biomarker for psychiatric disorders.