[Expectations and expectancies as a core principle in functional somatic symptoms: Evidence and clinical implications].

Expectation and expectancies play a central role in current etiological models of functional somatic symptoms and their clinical manifestations as functional disorders, bodily distress disorder and somatic symptom disorder. Their effects have been shown with respect to symptom development, symptom persistence and treatment outcomes. Handling expectations and expectancies is therefore an important task in their prevention and management, from primary care to psychotherapy. This review presents current evidence concerning the role of expectation and expectancies in the etiology and maintenance of functional somatic symptoms, and how to address them in transdisciplinary treatment.