Exploring the course of functional somatic symptoms (FSS) from pre- to late adolescence and associated internalizing psychopathology – an observational cohort-study

Abstract Background Functional somatic symptoms (FSS), which commonly cannot be attributed to well-defined organic pathology, often co-occur with internalizing psychopathology and fluctuate throughout different life stages. We examined FSS courses throughout adolescence, and the association between preadolescent FSS, FSS severity and internalizing psychopathology at late adolescence. Methods Data from the Copenhagen Child Cohort (CCC2000) were utilized from assessments at ages 11–12 years (preadolescence; T0) and 16–17 years (late adolescence; T1). Self-report questionnaire and interview data on FSS, internalizing psychopathology, chronic medical conditions, and sociodemographic data from Danish national registers were available for 1285 youths. FSS courses were categorized into persistent (high FSS at T0 & T1), remission (high FSS only at T0), incident (high FSS only at T1) or no FSS (no FSS at T0 & T1). Multiple linear and multinomial logistic regressions were conducted to investigate the FSS/psychopathology association. Results 1.8% of adolescents fell into the persistent FSS course group throughout adolescence. Higher preadolescent FSS predicted FSS (b = 0.07, p