The aim of this study was to determine whether advanced puberty at age 9 and 10 years, relative to that in same-aged peers, predicts current and/or new-onset self-injurious thoughts and behaviors (SITBs). New predictors of SITBs in preadolescence are urgently needed to address this escalating public health crisis of youth self-harm and suicidality.

Data from the baseline, 1-year, and 2-year waves of the Adolescent Brain and Cognitive Development Study were used. Bayesian mixed-effects models were estimated for test and replication split halves, and tested whether relatively advanced youth-reported pubertal development at 9 or 10 years predicted SITBs (suicidal ideation, suicide attempts, and nonsuicidal self-injury) as reported by preadolescents (each wave) and their caregiver (baseline, 2-year follow-up) in a computerized version of the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS). Preadolescents with baseline self-reported puberty, KSADS (N = 8,708; 44.6% female; 60.8% White non-Hispanic), and demographic information were included.

Baseline preadolescent-reported puberty predicted the presence of any SITB before or at baseline (odds ratio = 1.50, 95% credible interval = 1.23-1.85) and the new-onset SITBs between baseline and 2-year follow-up in preadolescents SITB-naive at baseline (odds ratio = 2.26, 95% credible interval = 1.66-3.21).

Preadolescents reporting relatively advanced puberty were more likely to have experienced SITBs and, if SITB naive, were more likely to experience the onset of SITBs across the following 2 years. Findings were not explained by child psychopathology or other familial and psychosocial factors known to predict SITBs. Screening preadolescents for advanced puberty at ages 9 and 10 years and applying targeted suicide screening for those youth showing advanced puberty should be considered in primary care and mental health settings.

Analyzing data from the Adolescent Brain and Cognitive Development (ABCD) study, the authors found that adolescents reporting advanced puberty at age 9 to 10 were more likely to have experienced self-injurious thoughts and behaviors (SITB) and, if SITB naive, were more likely to experience the onset of SITBs over the following 2 years. These findings were not explained by other child mental health problems or familial or social factors known to predict these behaviors. The authors recommend screening preadolescents for advanced puberty and applying targeted suicide screening for those youth showing advanced puberty in primary care and mental health settings.