Personality functioning in adolescents and its association with health-related quality of life and physical fitness

Adolescence is a crucial developmental phase marked by major physical, cognitive, and psychosocial changes that shape self-perception and relationships, with lasting effects on mental and physical health. Personality functioning, a core concept in modern diagnostic systems, such as the International Classification of Diseases (ICD-11), offers a dimensional framework that incorporates key developmental domains such as identity, self-direction, empathy, and intimacy. Early detection of impairments in these areas is essential to promote mental and physical well-being and to prevent the onset of mental disorders. In addition, an improvement in physical fitness (PF) appears to be associated with a significantly lower risk of developing mental disorders. Thus, this study aimed to examine associations between the dimensions of personality functioning, health-related quality of life (HRQoL), and PF in adolescents. A total of 186 adolescents (48.3% girls; mean age 15.6 ± 0.6 years) completed the KIDSCREEN-10, the Levels of Personality Functioning Questionnaire (LoPF-Q) 12-18, and the standardized German motor fitness test (DMT 6-18). Significant negative moderate and large correlations were found between HRQoL and overall personality dysfunction, as well as the identity, self-direction, empathy, and intimacy development domains. Additionally, PF showed significant negative moderate correlations with overall personality dysfunction, particularly with intimacy. Multiple regression analyses revealed that self-direction and intimacy were significantly negatively associated with the HRQoL, while intimacy was negatively associated with PF. Impaired personality functioning, particularly in self-direction and intimacy, was strongly associated with reduced HRQoL and PF in adolescents. These findings highlight the importance of recognizing emerging personality difficulties early and providing timely support, as this can play a vital role in promoting both mental and physical health during adolescence and later in life.