Leaders and followers in adolescent close friendships: susceptibility to peer influence as a predictor of risky behavior, friendship instability, and depression.

Adolescents' susceptibility to peer influence was examined as a marker of difficulties in the general process of autonomy development that was likely to be related to deficits across multiple domains of psychosocial functioning. A laboratory-based assessment of susceptibility to peer influence in interactions with a close friend was developed and examined in relation to corollary reports obtained from adolescents, their mothers, and close peers at ages 13 and 14. As hypothesized, observed susceptibility to peer influence with a close friend predicted future responses to negative peer pressure, but it was also related to broader markers of problems in functioning, including decreases in popularity, and increasing levels of depressive symptoms, over time. Susceptibility to peer influence was also linked to higher concurrent levels of substance use, externalizing behavior, and sexual activity. Results are interpreted as reflecting the central role of establishing autonomy with peers in psychosocial development.