Timing and tempo of pubertal development and self-harm and suicidality in adolescents: a follow-up study in the Danish National Birth Cohort

Purpose To investigate associations between pubertal timing and tempo and self-harm, suicidal ideation, plans, and suicide attempts in 8,063 adolescents. Methods Tanner stages, age at menarche, first ejaculation, and voice break were self-assessed half-yearly throughout puberty. Timing and tempo of pubertal markers were analysed continuously and categorically (earlier/faster, average, or later/slower). Information on self-reported self-harm, suicidal ideation, plans, and suicide attempts was obtained from the Danish National Birth Cohort 18-year follow-up. The Danish National Patient Register was used to identify clinically diagnosed suicide attempts, which were combined with self-reported suicide attempts into a composite outcome. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using logistic regression models. Results In girls, earlier timing was associated with higher odds of self-harm, suicidal ideation, and plans. For each year of earlier timing, breast development (OR = 1.19 (95% CI: 1.10;1.28)) and pubic hair development (OR = 1.23 (95% CI: 1.13;1.34)) were associated with suicidal ideation. Faster tempo of breast and pubic hair development was associated with higher odds of suicidal plans. In boys, earlier pubertal timing was associated with higher odds of suicidal ideation. For each year of earlier timing, pubic hair development (OR = 1.17 (95% CI: 1.05;1.32)) and voice break (OR = 1.14 (95% CI: 1.04;1.25)) were associated with suicidal ideation. Pubertal timing was not associated with suicide attempts in both sexes. Conclusion Earlier pubertal timing was associated with self-harm, suicidal ideation, and plans in girls, and suicidal ideation in boys. Early puberty may mark vulnerability for adverse mental health outcomes and may inform targeted prevention.