Fig. 3

Observational and causal links between age at menarche and depression. A Standardised betas of age at menarche predicting adolescent depressive symptoms, based on linear regressions unadjusted and adjusted for covariates and symptoms at age 8, one-sample Mendelian randomisation (MR), and negative control MR with 8-year depressive symptoms as the outcome. B Standardised odds ratios of age at menarche predicting depression diagnoses during adolescence, based on logistic regressions unadjusted and adjusted for covariates, and one-sample MR. In both panels, the orange dashed line represents the smallest effect size of interest for the observational analysis; the blue dashed line represents the smallest effect size of interest for the MR. NB: 95% confidence intervals are presented to show the precision of the estimates, but all statistical tests for depression outcomes were pre-specified to be one-tailed, meaning that the visual interpretation of the CIs in relation to the point null and smallest effect sizes of interest differs from the test result (described in text) in places