Diagnostic accuracy of the Dutch version of the Somatic Symptom Disorder - B Criteria Scale (SSD-12) compared to the Whiteley Index (WI) and PHQ-15 in a clinical population

C M van der Feltz-Cornelis; J Sweetman; J F van Eck van der Sluijs; C A D Kamp; L de Vroege; E de Beurs

doi:10.1016/j.jpsychores.2023.111460

Diagnostic accuracy of the Dutch version of the Somatic Symptom Disorder - B Criteria Scale (SSD-12) compared to the Whiteley Index (WI) and PHQ-15 in a clinical population

J Psychosom Res. 2023 Oct:173:111460. doi: 10.1016/j.jpsychores.2023.111460. Epub 2023 Aug 12.

Authors

C M van der Feltz-Cornelis¹, J Sweetman², J F van Eck van der Sluijs³, C A D Kamp⁴, L de Vroege⁵, E de Beurs⁶

Affiliations

¹ MHARG, Department of Health Sciences, University of York, York, United Kingdom; Institute of Health Informatics, University College London, London, United Kingdom; Clinical Centre of Excellence for Body, Mind and Health, GGz Breburg, Tilburg, the Netherlands. Electronic address: christina.vanderfeltz-cornelis@york.ac.uk.
² MHARG, Department of Health Sciences, University of York, York, United Kingdom.
³ Clinical Centre of Excellence for Body, Mind and Health, GGz Breburg, Tilburg, the Netherlands; Mentaal Beter, Utrecht, the Netherlands.
⁴ Clinical Centre of Excellence for Body, Mind and Health, GGz Breburg, Tilburg, the Netherlands; Department Tranzo, Tilburg School of Social and Behavioral Sciences, Tilburg University, Tilburg, the Netherlands; Psychologiepraktijk Eline Biesheuvel, Alkmaar, the Netherlands.
⁵ Clinical Centre of Excellence for Body, Mind and Health, GGz Breburg, Tilburg, the Netherlands; Department Tranzo, Tilburg School of Social and Behavioral Sciences, Tilburg University, Tilburg, the Netherlands.
⁶ Clinical Psychology Department, Leiden University, Leiden, the Netherlands; Department of Research, Arkin GGZ, Amsterdam, the Netherlands.

PMID: 37607421
DOI: 10.1016/j.jpsychores.2023.111460

Abstract

Objective: Somatic Symptom and Related Disorders(SSRD) are characterised by an intense focus on somatic symptoms that causes significant distress. A self-report scale developed to assess distress as symptom-related thoughts, feelings, and behaviors (SSD-12) has proved to be a reliable, valid and time-efficient measure for Somatic Symptom Disorder(SSD). This cross-sectional study aimed to compare the SSD-12 with psychiatric assessment as gold standard in a Dutch clinical population for SSRD compared to other widely used measures.

Methods: Data were collected from adult patients visiting a specialised mental health outpatient clinic for SSRD in the Netherlands, between 2015 and 2017. Analyses included item evaluation, scale reliability, construct validity, diagnostic utility and cut points. Performance of SSD-12, Whiteley Index(WI) and PHQ-15 were compared in Receiver operating characteristics (ROC) curves.

Results: 223 patients with SSD, Functional Neurological Disorder, Illness Anxiety(IA) and no SSRD participated. SSD-12 items were normally distributed; total scores correlated with measures of health anxiety, anxiety and depression. The optimal cut point for the SSD-12 was 22 (sensitivity 75.9%, specificity 63.6%). The ROC area under the curve for SSD-12 was 0.75 compared to 0.68 for the WI and 0.65 for the PHQ-15. Combinations of those questionnaires did not yield better results than for the SSD-12 alone.

Conclusion: The SSD-12 alone outperformed the WI and PHQ-15 and combined scales in effectively distinguishing SSRDs from other mental disorders. This may suggest that distress is a more accurate indicator of SSRD than earlier diagnostic criteria as operationalised in the WI and PHQ-15.

Keywords: SSD12; Screening; Sensitivity; Somatic Symptom Disorder; Specificity; Validation.

MeSH terms

Adult
Conversion Disorder*
Cross-Sectional Studies
Humans
Medically Unexplained Symptoms*
Reproducibility of Results
Somatoform Disorders / diagnosis
Somatoform Disorders / psychology
Surveys and Questionnaires