Overcoming challenges as part of maturation: Evidence for a personality “disruption” in adolescence from a two-cohort HEXACO study

Mean-level increases on personality traits are broadly considered indicative of maturation, a process underpinned by self-regulation. However, self-regulation decreases in early to mid-adolescence, prompting expectations of personality declines - a trend termed the “disruption” hypothesis. This study examines a particularly vulnerable period in adolescence and assesses mean-level changes in the six HEXACO traits - rHonesty-Humility, Emotionality, Extraversion, Agreeableness, Conscientiousness, and Openness to experience, contributing to a still very limited body of longitudinal HEXACO research in adolescence. Additionally, it explores cross-sectional associations with depressive symptoms. Data were collected from two adolescent cohorts assessed at baseline (age 13) and again after one year (Cohort 1, 2017–2018; N = 222) or after two years (Cohort 2: 2018–2020; N = 588). Participants were Dutch high school students (39.19% girls in Cohort 1, 54.5% in Cohort 2). Personality was assessed using the Brief HEXACO Inventory, and depressive symptoms with the Center for Epidemiologic Studies Depression Scale for Children. Conscientiousness declined in Cohort 1. In Cohort 2, Honesty-Humility, Extraversion, Agreeableness, and Conscientiousness decreased, while Emotionality increased for girls and decreased for boys. Openness to experience remained stable. Across cohorts, boys showed consistently lower Honesty-Humility and Emotionality than girls. Declining traits were cross-sectionally negatively associated with depression, while Emotionality and Openness showed positive associations. Findings show a pattern of disruption, though small declines may reflect adaptive learning. However, lower trait scores were linked to higher depressive symptoms, highlighting the need for research on individual developmental trajectories. • Personality traits show declines in early to mid-adolescence. • All HEXACO traits are cross-sectionally linked to depressive symptoms at age 13. • Lower scores on declining traits are linked to higher depressive symptoms. • Trait declines may reflect temporary self-regulation disruptions in early adolescence.