LAUSR

Adolescent loneliness can have detrimental effects on physical and mental health, but there is limited understanding of its antecedents in infancy and childhood. A 20-year longitudinal, multi-informant, and multi-methods study (first data collection in 1998) was conducted to examine mechanisms underlying adolescent loneliness (N = 128, 52% boys, Mage_baseline  = 1.23, SD = 0.02, 99% White, recruitment in Dutch urban, healthcare centers). Structural equation modeling showed that high infant behavioral inhibition (BI) was indirectly associated with high loneliness during adolescence via high childhood social withdrawal. This indirect effect was equally strong during early, middle, and late adolescence. Contrary to expectations, infant parenting did not moderate the relation between BI and social withdrawal. The results suggest a developmental cascade with infant BI showing long-lasting indirect effects on adolescent loneliness up to 20 years later via childhood social withdrawal.