Psychometric properties of the Persian version of the somatic symptom disorder-B Criteria Scale (SSD-12) in community and clinical samples

Somatic Symptom Disorder-B criteria scale (SSD-12): Psychometric properties of the French version and associations with health outcomes in a population-based cross-sectional study

OBJECTIVE

The 12-item Somatic Symptom Disorder-B Criteria Scale (SSD-12) is a self-reported questionnaire designed to assess the B criteria of the DSM-5 somatic symptom disorder. In this cross-sectional study, we aimed to examine the psychometric properties of the SSD-12 French version and associated health outcomes.

METHODS

Participants were volunteers from the population-based CONSTANCES cohort who reported at least one new symptom that occurred between March 2020 and January 2021. Depressive symptoms were measured with the Center for Epidemiologic Studies-Depression scale (CES-D).

RESULTS

A total of 18,796 participants completed the SSD-12. The scree plot was consistent with a 1-factor structure, while goodness-of-fit indices of the confirmatory factorial analyses and clinical interpretability were consistent with a 3-factor structure (excluding the item 7): 'Perceived severity', 'Perceived impairment', 'Negative expectations'. The Cronbach's α coefficients of the total and factors scores were 0.90, 0.88, 0.84 and 0.877, respectively. The total score was associated with depressive symptoms (Spearmann's rho: 0.32), self-rated health (-0.46), the number of persistent symptoms (0.32), and seeking medical consultation (odds ratio [95% confidence interval] for one interquartile range increase: 1.51 [1.48-1.54]). Among participants seeking medical consultation, those with higher SSD-12 scores were more likely to have their symptoms attributed to "stress/anxiety/depression" (1.32 [1.22-1.43]) and "psychosomatic origin" (1.25 [1.20-1.29]), and less to "COVID-19" (0.89 [0.85-0.93]).

CONCLUSION

While the SSD-12 French version can be used as a unidimensional tool, it also has a 3-factor structure, somewhat different from the DSM-5 theoretical structure, with high internal consistency and clinically meaningful associations with other health outcomes.

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

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.

Differences in psychometric characteristics of outpatients with somatic symptom disorder from general hospital biomedical (neurology/gastroenterology), traditional Chinese medicine, and psychosomatic settings

Objective

The aim of this study is to investigate the psychometric characteristics of outpatients diagnosed with somatic symptom disorder (SSD) in biomedical, Traditional Chinese Medicine (TCM) and psychosomatic settings.

Materials and methods

A total of 697 participants who completed SCID-5 and questionnaires were presented in our former study, as 3 of them had missed questionnaire data, a total of 694 participants are presented in this study. A secondary analysis of the psychometric characteristics of Somatic Symptom Disorder-B Criteria Scale (SSD-12), Somatic Symptom Severity Scale of the Patient-Health Questionnaire (PHQ-15), Patient Health Questionnaire-9 (PHQ-9) and General Anxiety Disorder-7 (GAD-7) is done to compare differences among outpatients from the three settings of medical specialties.

Results

Based on the DSM-5 criteria, 90 out of 224 (40.2%) participants enrolled in biomedical departments (represented by neurology and gastroenterology departments), 44/231 (19.0%) in TCM departments, and 101/239 (42.3%) in the psychosomatic medicine departments were diagnosed with SSD. The scores of PHQ-15 in the biomedical, TCM and psychosomatic settings were 11.08 (± 4.54), 11.02 (± 5.27) and 13.26 (± 6.20); PHQ-9 were 10.43 (± 6.42), 11.20 (± 5.46) and 13.42 (± 7.32); GAD-7 were 8.52 (± 6.22), 9.57 (± 5.06) and 10.83 (± 6.24); SSD-12 were 22.26 (± 11.53), 22.98 (± 10.96) and 25.03 (± 11.54) respectively. The scores of PHQ-15, PHQ-9 and GAD-7 in SSD patients were significantly higher in psychosomatic departments than that in biomedical settings (p < 0.05). The cutoff point for SSD-12 was ≥16 in total patients; 16, 16, 17 in biomedical, TCM and psychosomatic settings, respectively. The cutoff point for PHQ-15 was found to be ≥8 in total patients; 8, 9, 11 in biomedical, TCM and psychosomatic settings, respectively.

Conclusion

SSD patients from psychosomatic departments had higher level of somatic symptom severity, depression and anxiety than from TCM and biomedical settings. In our specific sample, a cutoff point of ≥16 for SSD-12 could be recommended in all three settings. But the cutoff point of PHQ-15 differs much between different settings, which was ≥8, 9, and 11 in biomedical, TCM, and psychosomatic settings, respectively.