Jonathan Schaefer

Background Psychopathology and risky behaviors increase during adolescence, and understanding which adolescents are most at risk informs prevention and intervention efforts. Pubertal timing relative to same‐sex, same‐age peers is a known correlate of adolescent outcomes among both boys and girls. However, it remains unclear whether this relation is better explained by a plausible causal process or unobserved familial liability. Methods We extended previous research by examining associations between pubertal timing in early adolescence (age 14) and outcomes in later adolescence (age 17) in a community sample of 2,510 twins (49% boys, 51% girls). Results Earlier pubertal timing was associated with more substance use, risk behavior, internalizing and externalizing problems, and peer problems in later adolescence; these effects were small, consistent with previous literature. Follow‐up co‐twin control analyses indicated that within‐twin‐pair differences in pubertal timing were not associated with within‐twin‐pair differences in most adolescent outcomes after accounting for shared familial liability, suggesting that earlier pubertal timing and adolescent outcomes both reflect familial risk factors. Biometric models indicated that associations between earlier pubertal timing and negative adolescent outcomes were largely attributable to shared genetic liability. Conclusions Although earlier pubertal timing was associated with negative adolescent outcomes, our results suggests that these associations did not appear to be caused by earlier pubertal timing but were likely caused by shared genetic influences.