Personality disorder symptoms were investigated in a community sample of young people (n = 714) to assess their relationship over time with well-being during adolescence and the emergence of intimacy in early adulthood. Drawing on Erikson's theory of psychosocial development, changes in adolescent well-being were conceptualized as indirect indicators of identity consolidation. Cluster B personality disorder symptoms (borderline, histrionic, and narcissistic symptoms) were conceptualized to represent "identity diffusion" -- i. e. maladaptive personality traits that usually resolve during the identity crisis of adolescence. Latent growth models were used in 2 age cohorts to assess (1) interrelationships between Cluster B symptoms, well-being, and intimacy at mean ages 13.8 and 18.6 years; and (2) associations between their developmental trajectories over the next 6 years. As expected, higher personality disorder symptoms were associated with lower well-being during adolescence, and declines in personality disorder symptoms over time were associated with corresponding gains in well-being. Consistent with Erikson's developmental theory, there was an inverse relationship between Cluster B symptoms and intimacy that increased in strength as young people entered adulthood. As an indicator of successful identity consolidation, well-being was significantly associated with intimacy in female adolescents and young adults.