Functional somatic symptoms in adolescence and young adulthood: Personal vulnerabilities and external stressors

Functional somatic symptoms (FSS) are physical symptoms not fully explained by a well-defined somatic or psychological illness. FSS are common in young people and can become very disabling. Unfortunately, the etiology of FSS and how they can best be treated remains largely unclear.
In this thesis we aimed to provide more insight into risk factors for FSS in young people. We investigated the role of perfectionism, sleep problems and severe life events in the development of FSS in young people from a population cohort named TRAILS. In addition, the effectiveness of psychological treatments for FSS in children was systematically reviewed.
We found that perfectionism sensitizes adolescents for higher levels of FSS. Sleep problems were identified as a vulnerability factor for musculoskeletal pains in females, but not for headaches or abdominal pain. Severe life events predicted various FSS, especially when adolescents already suffered from a depression or anxiety disorder. Surprisingly, especially life events which had nothing to do with illness were responsible for an increase in FSS as opposed to, for example, having a severely ill parent. The systematic review revealed that psychological treatments can improve symptoms, disabilities and school attendance in children with FSS. However, included populations, treatments and the effectiveness of investigated treatments differed substantially between studies. Studies were thus hard to compare and heterogeneity in effectivity between studies could not be explained. Considering our findings in the general population, psychological treatments would probably be more effective when they would be adapted to personal vulnerabilities.