Background: Despite an increase in mental health problems, with psychosomatic symptoms having been observed in new generations of Swedish youth, the extent to which these problems correspond to an increase in adult mental problems is unknown. The present study investigates whether Swedish adolescents with high levels of psychosomatic symptoms are at risk of developing depression and anxiety problems in adulthood and whether sex moderates any association. Moreover, we aim to understand whether different clusters of youth psychosomatic symptoms – somatic, psychological and musculoskeletal – have different impacts on adult mental health. Methods: One thousand five hundred forty-five Swedish adolescents – aged 13 (49%) and 15 (51%) – completed surveys at baseline (T1) and 3 years later (T2); of them, 1174 (61% females) also participated after 6 years (T3). Multivariate logistic models were run. Results: Youth with high levels of psychosomatic symptoms had higher odds of high levels of depressive symptoms at T2 and T3. Moreover, psychosomatic symptoms at T1 predicted a high level of anxiety symptoms and diagnoses of anxiety disorders at T3. When analyzed separately, musculoskeletal symptoms predicted higher odds of having high levels of depressive symptoms at T2 and T3 while somatic symptoms predicted high levels of anxiety symptoms at T2. Moreover, somatic symptoms at T1 predicted diagnoses of depression and anxiety disorders at T3. Sex did not moderate any of the relationships. Conclusions: The study supports the idea that an increase in mental health problems, such as psychosomatic symptoms, can seriously impact the psychological health of new generations of young adults.

The implementation of preventive interventions is considered a crucial aspect of their success. However, few studies have investigated which components of implementation are most important.