Abstract
Limited research addresses personality shifts from mid-adolescence to emerging adulthood, alongside well-being. This study analysed Big Five trait and narrative identity change (thematic coherence, causal coherence, resolution valence) across 111 individuals (46.8% female) aged 15/16 who were reassessed at age 21. Neuroticism, conscientiousness, thematic coherence, and causal coherence rose, lacking stability for the latter two; extraversion decreased. Thematic coherence correlated with agreeableness and lower conscientiousness in mid-adolescence, and lower depression at emerging adulthood. Causal coherence correlated with conscientiousness, and lower depression. Extraversion, agreeableness, conscientiousness, and openness correlated with better well-being, particularly at emerging adulthood. Causal coherence correlated with self-esteem; mid-adolescents’ negative resolution valence predicted later depression and poorer self-esteem, controlling for traits. Findings imply distinct trait and narrative identity trajectories.