Somatic Symptom Disorder according to DSM-5: development and validation of a new self-report measure (SSD-B)

• Applicant: Anne Toussaint, Ph.D.
• Subject Area: Personality Psychology, Clinical and Medical Psychology, Methodology
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 254436317

In May 2013, the American Psychiatric Association published the latest version of the Diagnostic and Statistical Manual of Mental Disorders: DSM-5. This version includes significant improvements in the domain of somatoform type disorders to improve the reliability and clinical utility of the diagnoses. In particular, the new Somatic Symptom Disorder no longer includes the controversial need for organic explicability of symptoms. In contrast, the presence of at least one relevant positive psychological characteristic (B criteria) accompanying the physical symptoms is required: (I) disproportionate and persistent thoughts about the seriousness of one's symptoms, (2) persistently high level of anxiety about health or symptoms, (3) excessive time and energy devoted to these symptoms or health concerns. It is critical to diagnose these patients early to prevent chronification, inappropriate health care use and improve patient care. Although they are no replacement for the gold standard Structured Clinical Interview for DSM-Disorders, self-report questionnaires can be a practical and efficient diagnostic aid. There are scales available to assess physical symptoms (e.g. PHQ-15), however, there is currently no questionnaire to directly assess the new B criteria. The objective of our project is to develop a reliable and valid instrument for this purpose. So far a preliminary version (SSD-B) has been developed and tested on a pilot outpatient psychosomatic sample (n = 156). A confirmatory factor analysis confirmed a three factor structure of a refined 12 item version which was originally formed according to the three sub-criteria. Reliability estimates, convergent and divergent validity analyses suggest that the questionnaire has promising content-related and psychometric properties. In order to further develop and extend the instrument to enable case identification, severity and course measurement, the current proposal was formed. The future project has been divided into five parts. Phase I will involve the further development of the full version of SSD-B and the development of a short version. These versions will be validated in both an in- and out-patient sample in Phase II. To broaden the potential use of SSD-B, an English version will be created according to the state of the art translation procedures and then validated in an English-speaking sample (External Project I). Age- and gender-related norms of SSD-B will be formed in a general population sample (External Project II). In the final phase, the outcomes of the project will be disseminated in publications, at local and international conferences and within health-care networks (Phase III). The outcome of the complete development and validation process of SSD-B will hopefully enable a more targeted, sensitive and earlier detection of somatic symptom disorder so that more pragmatic and quality of life-related interventions can be offered to these patients in the future.

• DFG Programme: Research Grants
• Participating Persons: Professor Dr. Bernd Löwe; Alexandra Murray, Ph.D.