Objectives: 

The main goal of this project is to assess concurrent and predictive validity of FD, SSD (DSM-5) and BDS (ICD-11) diagnostic criteria used in mental health care and to thereby identify a subset of the most valid and predictive diagnostic criteria that could form an evidenced-based basis for future diagnostic classification systems. ESR5 will start by developing a common methodology toolbox that will be used across the ETUDE project. Online methodology will be developed to construct a prospective cohort of patients that will be followed over one year to allow epidemiological analyses. Various diagnostic criteria of FD, SSD, and BDS will be assessed at baseline. The severity of somatic symptoms, health related anxiety, functional impairment, and diagnostic status will be assessed at baseline, after 6 months and after 1 year. Concurrent and predictive validity will be measured for each diagnostic criteria with regard to somatic symptom severity, health related anxiety functional status, and diagnostic status. A set of the most valid diagnostic criteria will be identified and used for future development of diagnostic classification systems regarding FD, SSD, and BDS. The predictive validity of the individual diagnostic criteria will be compared, the diagnostic overlap of FD, SSD and BDS will be described and their interrelationship will be clarified. Eventually recommendations for future diagnostic classification will be derived.

Expected Results: 

1. Assessment of concurrent and predictive validity of diagnostic criteria for FD
2. Identification of a subset of the most valid and predictive diagnostic criteria of FD with regard to symptom persistence
3. Recommendations for future diagnostic criteria based on the results of this study

Planned secondments and research visits: 

1. GAIA A.G., Hamburg, Germany (Dr. Weiss); Start: Month 12; Duration: 2 months; Aim: prepare patient recruitment in different health care settings using online methodology
2. Dimence mental health care (Dimence Group), Specialist Centre for Functional symptoms & Somatic symptom disorders (Dr. Tak), University of Groningen, Groningen, Netherlands; Start: Month 14; Duration: 2 months; Aims: initiate patient recruitment at Dimence Group
3. Technical University Munich (TUM-Med), Department of Psychosomatic Medicine and Psychotherapy (Prof. Lehnen), Munich, Germany; Start: Months 17; Duration: 2 months; Aims: implement diagnostic criteria set in mechanistic studies, initiate patient recruitment for validity studies at TUM-Med
4. University Medical Center Groningen (UMCG), Departments of Psychiatry and Internal Medicine (Prof. Rosmalen), Groningen, Netherlands; Start: Month 21; Duration: 5 months; Aim: analyse predictive validity of criteria in LifeLines cohort somatic health care