The long shadow of social withdrawal: The impact of social withdrawal in adolescence on adult developmental outcomes - The TRAILS study.

Social withdrawal in late childhood and adolescence is linked to long-term developmental challenges, yet its unique impact on adult adaptive functioning remains understudied. This TRAILS study (N = 1,798 in the population cohort, M (SD) age at T1: 11.1 (0.6), 49% boys, 86.5% ethnically Dutch, M (SD) age at T7: 28.9 (0.6); N = 405 in the high-risk cohort, M (SD) age at T1: 11.1 (0.5), 66% boys, 97.6% ethnically Dutch, M (SD) age at T7: 29.6 (0.7)) examined whether social withdrawal during the ages of 11 to 16 predicted the achievement of developmental milestones by age 29, including romantic competence, residential autonomy, friendship satisfaction, work competence, and financial competence. Higher levels of social withdrawal consistently predicted lower likelihood of having achieved these milestones by age 29 (median OR = 0.76 in both cohorts), even after controlling for peer victimization, cognitive abilities, and family background measured in early adolescence. These effects were consistent across cohorts and gender. Sensitivity analyses that accounted for genetic confounding and clinical conditions (e.g., autism, depression) further supported the findings. These results highlight social withdrawal as a critical risk factor for developmental disadvantages, urging early interventions to foster social engagement and mitigate long-term maladjustment.