Association between menstrual cycle characteristics and mental health in early adolescence.
Adolescence marks a critical window for the emergence of mental health problems and reproductive maturation. Menstrual cycle characteristics - including pubertal timing, cycle regularity, menstrual pain, and premenstrual symptoms -may capture biological and experiential processes relevant to psychopathology. However, evidence linking menstrual features to a broad range of mental health outcomes, including ADHD symptoms, remains limited. Using data from the Adolescent Brain Cognitive Development (ABCD) Study (v6.1 N = 5,678 biological females; 17,567 post-menarche observations across 7 waves), we examined associations between reproductive timing, menstrual characteristics and symptoms of attention-deficit/hyperactivity disorder (ADHD), depression, and anxiety symptoms across repeated assessments in early adolescence using linear mixed-effects models with crossed random intercepts for site, family, and participant. Two co-primary model specifications were used: without BMI (M1, full sample) and with BMI (M2). False discovery rate correction was applied across outcomes. Earlier age at menarche was specifically associated with higher depression symptom scores (B = -0.087, pFDR < 0.001), with attenuation after BMI adjustment. Greater gynaecologic age (time since menarche TSM) also associated with higher depression scores (B = + 0.118, pFDR < 0.001) independent of chronological age and pubertal timing. Among girls with established cycles (TSM ≥ 2 years), irregular cycles were associated with higher depression and anxiety, whereas associations with ADHD did not remain after BMI adjustment. Long cycles were associated with anxiety only. Severe menstrual pain and premenstrual symptom severity showed dose-response associations with depression, anxiety, and ADHD that were robust to BMI adjustment. The association between irregular cycles and depression, and between long cycles and depression and anxiety, strengthened significantly with increasing gynaecologic age, while symptom burden associations were consistent throughout the post-menarcheal period. Menstrual symptom burden particularly severe pain and premenstrual distress and earlier menarche were consistently associated with higher levels of psychiatric symptoms in adolescent girls. These findings highlight menstrual health as a potentially informative dimension of adolescent mental health assessment. When girls present with significant menstrual symptoms, assessment of emotional wellbeing may be warranted.