Tell Me Something I Don't Know: Self-Disclosure, Mental Health, Relationship Quality, and Contextual Factors from Adolescence to Adulthood

This study examines links from self-disclosure with best friends in adolescence to contemporaneous and long-term relationship quality and internalizing symptoms from adolescence to adulthood. A diverse community sample of adolescents (N = 184) participated in survey and observational measures annually from ages 13 through 29, along with close friends and romantic partners. Random Intercept Cross-Lagged Panel Models were used to parse markers of within-individual change across age 13 to 18. Long-term longitudinal path models also investigated cascading associations from self-disclosure, relationship quality, and internalizing symptoms, on aggregate, from adolescence to adulthood. Analyses considering key demographic and neighborhood contextual factors explored potential developmental moderation. Findings are interpreted through the lens of iterative social learning: adolescent development is shaped by social input, to which they are particularly attuned. The best friendship, a key source of support, serves as a foundational context for supportive, vulnerable interactions in adolescence that pan forward into adulthood. Adolescents situated in high-quality relationships engage in more self-disclosure, and high self-disclosure encourages self-disclosure by others; prompting a positive “upward spiral” of disclosure and supportive behaviors that persists into adulthood. Ultimately, the aim of this work is to identify developmental trajectories associated with self-disclosure in adolescent best friendships, to best support teens’ functional social learning across the lifespan.