Validity and sensitivity to change of the Somatic Symptom Disorder-B Criteria Scale (SSD-12) in a clinical population

Reliability and Validity of the Korean Version of the Somatic Symptom Disorder-B Criteria Scale in a Clinical Population

OBJECTIVE

This study aimed to develop and validate the Korean version of the Somatic Symptom Disorder-B Criteria Scale (SSD-12) in outpatients at a psychiatric clinic and assess its diagnostic accuracy.

METHODS

A total of 207 patients completed SSD-12. For the diagnostic accuracy of SSD-12, the somatic symptom disorder (SSD) section of the structured clinical interview for DSM-5 disorders-research version (SCID-5-RV) was used. The SSD-12 construct and concurrent validity were assessed by examining the correlations with Generalized Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9), PHQ-15, 5-level EQ-5D version (EQ-5D-5L), and World Health Organization Quality of Life Brief Version (WHOQOL-BREF).

RESULTS

The SSD-12 had excellent internal consistency (Cronbach α=0.90). Confirmatory factor analysis revealed good fit indices for a general factor model (comparative fit index [CFI]=0.92, Tucker-Lewis index [TLI]=0.88, root mean square error of approximation [RMSEA]=0.10; 95% confidence interval [CI], 0.08-0.11) and a three-factor model (CFI=0.94, TLI=0.91, RMSEA=0.08; 95% CI, 0.07-0.10). The total SSD-12 score was significantly correlated with anxiety (GAD-7: r=0.53, p<0.001), depression (PHQ-9: r=0.52, p<0.001), physical symptom burden (PHQ-15: r=0.36, p<0.001), and quality of life (EQ-5D-5L: r=-0.40, p<0.001; WHOQOL-BREF: r=-0.51, p<0.001). SSD-12 demonstrated good accuracy (area under the curve=0.75, standard error=0.04; 95% CI, 0.68-0.82) with an optimal cut-off of 29.

CONCLUSION

The Korean SSD-12 demonstrates reliability and validity for diagnosing SSD in clinical setting.

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.

Helpful explanatory models for persistent somatic symptoms (HERMES): Results of a three-arm randomized-controlled pilot trial

OBJECTIVE

This three-arm randomized controlled trial aimed to test the efficacy of an etiological model for persistent somatic symptoms (PSS) translated into video-animated explanatory models in comparison to a control group, and to examine additional value of personalization of the explanatory models (i.e. possibility to choose information based on mechanisms of symptom persistence).

METHODS

Outpatients with PSS were shown one of three 15-min video animations: a) explanatory model without personalization, b) explanatory model with personalization, c) no explanatory model control group. Changes in somatic symptom severity (PHQ-15) and psychological burden related to somatic symptoms or associated health concerns (SSD-12) from baseline to one-month follow-up were the primary outcome. Health-related quality of life (SF-12) and perceived usefulness (USE) were also assessed.

RESULTS

Seventy-five patients with PSS were allocated to the study arms (Mage = 44.2 ± 13.3 years, 56% female). The study arms did not differ significantly on the primary outcomes. However, no explanatory model participants reported significantly greater mental quality of life improvements than explanatory model without personalization participants (Mdiff = 7.50 [0.43; 14.56]). Further, explanatory model with personalization participants rated the individual fit of the intervention significantly higher than no explanatory model participants (Mdiff = 2.05 [0.17; 3.93]). All groups rated credibility of the intervention as very high.

CONCLUSION

The HERMES materials seemed to have been too brief to improve symptom related outcomes. However, all three interventions were positively evaluated regarding their usefulness, particularly in case of additional personalization. Future studies should investigate potential effects of an increased intervention dose.

TRIAL REGISTRATION

DRKS00018803.

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.

The mediating effect of somatic symptom disorder between psychological factors and quality of life among Chinese breast cancer patients

Objective

We conducted this cross-sectional study to explore the mediating and predicting role of somatic symptom disorder (SSD) between psychological measures and quality of life (QOL) among Chinese breast cancer patients.

Methods

Breast cancer patients were recruited from three clinics in Beijing. Screening tools included the Patient Health Questionnaire-15 (PHQ-15), the Patient Health Questionnaire-9 (PHQ-9), the General Anxiety Disorder-7 scale (GAD-7), the Health Anxiety Scale (Whiteley Index-8, WI-8), the Somatic Symptom Disorder B-Criteria Scale (SSD-12), the Fear of Cancer Recurrence scale (FCR-4), the Brief Illness Perception Questionnaire (BIPQ-8), and the Functional Assessment of Cancer Therapy-Breast (FACT-B). Chi-square tests, nonparametric tests, mediating effect analysis, and linear regression analysis were used for the data analysis.

Results

Among the 264 participants, 25.0% were screened positive for SSD. The patients with screened positive SSD had a lower performance status, and a greater number of patients with screened positive SSD received traditional Chinese medicine (TCM) (p < 0.05). Strong mediating effects of SSD were found between psychological measures and QOL among patients with breast cancer after adjusting for sociodemographic variables as covariates (p < 0.001). The range of the percentage mediating effects was 25.67% (independent variable = PHQ-9) to 34.68% (independent variable = WI-8). Screened positive SSD predicted low QOL in physical (B = -0.476, p < 0.001), social (B = -0.163, p < 0.001), emotional (B = -0.304, p < 0.001), and functional (B = -0.283, p < 0.001) well-being, as well as substantial concerns caused by breast cancer (B = -0.354, p < 0.001).

Conclusion

Screened positive SSD had strong mediating effects between psychological factors and quality of life among breast cancer patients. Additionally, screened positive SSD was a significant predictor of lower QOL among breast cancer patients. Effective psychosocial interventions for improving QOL should consider the prevention and treatment of SSD or integrated SSD caring dimensions for breast cancer patients.

Improving quality of life in patients with rare autoimmune liver diseases by structured peer-delivered support (Q.RARE.LI): study protocol for a transnational effectiveness-implementation hybrid trial

BACKGROUND

Psychosocial support is a crucial component of adequate rare disease care, but to date psychosocial support needs of this patient population are insufficiently met. Within Q.RARE.LI, we strive to evaluate the effectiveness of a structured, transdiagnostic, and location-independent psychosocial support intervention in routine care of patients with rare autoimmune liver diseases in five countries and prepare its implementation.

METHODS

Within an effectiveness-implementation hybrid trial, we aim to a) investigate the effectiveness of the intervention in routine care in five diverse healthcare systems and b) assess implementation outcomes, examine and prepare the implementation context, and develop country-specific implementation strategies. To assess effectiveness, we will include N = 240 patients with rare autoimmune liver diseases. Within a two-armed randomized controlled trial (allocation ratio 1:1), we will compare structured and peer-delivered psychosocial support in addition to care-as-usual (CAU) with CAU alone. Outcomes will be assessed via electronic database entry prior to intervention, directly after, and at a three-month follow-up. Our primary effectiveness outcome will be mental health-related quality of life at post-assessment. Secondary outcomes include depression and anxiety severity, perceived social support, helplessness, and disease acceptance. Implementation outcomes will be assessed within a mixed-methods process evaluation. In a quantitative cross-sectional survey, we will examine perceived acceptability and feasibility in patients, peer-counselors, and healthcare providers involved in delivery of the intervention. In qualitative focus groups, we will analyze the implementation context and determine barriers and facilitators for implementation with different stakeholders (patients and/or representatives, peer-counselors, healthcare providers, health insurers). Based on these results, we will derive country-specific implementation strategies and develop a concrete implementation plan for each country.

DISCUSSION

The intervention is expected to help patients adjust to their disease and improve their mental quality of life. The transdiagnostic and location-independent program has the potential to reach patients for psychosocial support who are usually hard to reach. By preparing the implementation in five countries, the project can help to make low-threshold psychosocial support available to many patients with rare diseases and improve comprehensive healthcare for an often neglected group.

TRIAL REGISTRATION

ISRCTN15030282.

Persistent physical symptoms after COVID-19 infection and the risk of Somatic Symptom Disorder

OBJECTIVE

Evidence shows that many patients with COVID-19 present persistent symptoms after the acute infection. Some patients may be at a high risk of developing Somatic Symptom Disorder (SSD), in which persistent symptoms are accompanied by excessive and disproportionate health-related thoughts, feelings and behaviors regarding these symptoms. This study assessed the frequency of persistent physical symptoms and SSD and their associated factors in patients with confirmed COVID-19.

METHODS

We conducted a longitudinal retrospective study after the first two French lockdowns at the Lille University Hospital (France), including all patients with confirmed COVID-19. Persistent physical symptoms and excessive preoccupations for these symptoms were measured 8 to 10 months after the onset of COVID-19. The combination of the Patient Health Questionnaire-15 and the Somatic Symptom Disorder-B Criteria Scale was used to identify the individuals likely to present with SSD. Two linear regression models were performed to identify sociodemographic and medical risk factors of SSD.

RESULTS

Among the 377 patients with a laboratory-confirmed diagnosis, 220 (58.4%) completed the questionnaires. Sixty-five percent of the 220 included patients required hospitalization, 53.6% presented at least one persistent physical symptom and 10.4% were considered to present SSD. Female sex, older age, infection during the second wave and having probable PTSD were significantly associated with the severity of SSD and SSD was associated with a significantly higher healthcare use.

CONCLUSIONS

The identification of SSD should encourage clinicians to move beyond the artificial somatic/psychiatric dualism and contribute to a better alliance based on multi-disciplinary care.

Psychometric Evaluation of the Whiteley Index-8 in Chinese Outpatients in General Hospitals

Background: Excessive and persistent health anxiety is a common and disabling but often unrecognized illness. Therefore, screening patients for health anxiety is recommended in primary care. The aim of the present study was to examine the psychometric properties of an updated version of the eight-item Whiteley Index (WI-8) among outpatients in general hospitals in China. Methods: The presented data were derived from a multicenter cross-sectional study. The Chinese version of the WI-8 was administered to a total of 696 outpatients. Cronbach's alpha was used to evaluate the internal consistency of the scale. The validity of the scale was evaluated based on factor analysis and correlation analyses. To assess the discriminant ability, receiver operating characteristic (ROC) analysis was conducted. Results: Cronbach's alpha was 0.937, and it decreased (0.925) after deleting the new 8th item. Factor analysis extracted one factor accounting for 69.2% of the variance. Moderate correlations were found (0.414-0.662) between the WI-8 and General Anxiety Disorder (GAD-7), Patient Health Questionnaire-9 (PHQ-9), Patient Health Questionnaire-15 (PHQ-15) and Somatic Symptom Disorder B-criteria (SSD-12). The ROC curve indicated excellent discriminatory ability to discriminate among patients with health anxiety (AUC = 0.822). Conclusions: The new WI-8 version is a reliable and valid tool to screen for health anxiety in general hospital patients. We recommend the WI-8 as a useful screening tool for health anxiety.

Mental health specialist video consultations versus treatment as usual in patients with depression or anxiety disorders in primary care: study protocol for an individually randomised superiority trial (the PROVIDE-C trial)

BACKGROUND

Most people with mental disorders, including those with severe and chronic disorders, are treated solely by their general practitioner (GP). Nevertheless, specialised mental health care may be required for specific patients. Notably, the accessibility of mental health specialist care is mainly complicated by (a) long waiting times for an appointment with specialists, (b) long travel distances to specialists, particularly in rural and remote areas, and (c) patients' reservations about mental health specialist care (including fear of being stigmatised by seeking such care). To mitigate those barriers, technology-based integrated care models have been proposed. The purpose of this study is to examine the effectiveness and cost-effectiveness of a mental health specialist video consultations model versus treatment as usual in patients with depression or anxiety disorders in primary care.

METHODS

In an individually randomised, prospective, two-arm superiority trial with parallel group design, N = 320 patients with anxiety and/or depressive disorder will be recruited in general practices in Germany. The intervention includes a newly developed treatment model based on video consultations with focus on diagnostics, treatment planning, and short-term intervention by mental health specialists. We will systematically compare the effectiveness, cost-effectiveness, and adverse effects of this new model with usual care by the GP: the primary outcome is the absolute change in the mean depressive and anxiety symptom severity measured on the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS) from baseline to 6 months after baseline assessment. Follow-up in both groups will be conducted by blinded outcome assessors at 6 months and 12 months after baseline. The main analysis will be based on the intention-to-treat principle. We will optimise the likelihood of treatment effectiveness by strict inclusion criteria for patients, enhanced intervention integrity, and conducting a process evaluation.

DISCUSSION

To the best of our knowledge, this is the first confirmatory study on a video-based, integrated care model for the treatment of anxiety and depressive disorders in GP patients in Germany.

TRIAL REGISTRATION

ClinicalTrials.gov, United States National Institutes of Health NCT04316572 . Prospectively registered on 20 March 2020.

Diagnostic and treatment barriers to persistent somatic symptoms in primary care - representative survey with physicians

Background

Many patients consult their primary care physician with persistent somatic symptoms such as pain or sickness. Quite often these consultations and further diagnostic measures yield no medical explanation for the symptoms – patients and physicians are left in uncertainty. In fact, diagnostic and treatment barriers in primary care hinder timely health-care provision for patients suffering from persistent somatic symptoms (PSS). The significance of individual barriers is still unknown. We compare and quantify these barriers from the perspective of primary care physicians and identify subpopulations of primary care physicians who experience particular barriers as most severe.

Methods

We mailed a questionnaire to primary care physicians (PCP) in Germany and asked them which barriers they consider most important. We invited a random sample of 12,004 primary care physicians in eight federal states in Germany. Physicians provided anonymous mailed or online responses. We also mailed a postcard to announce the survey and a mail reminder. Main measures were Likert rating scales of items relating to barriers in the diagnosis and treatment of PSS in primary care. Information on demography and medical practice were also collected.

Results

We analyzed 1719 data sets from 1829 respondents. PCPs showed strongest agreement with statements regarding (1.) their lack of knowledge about treatment guidelines, (2.) their perceptions that patients with PSS would expect symptom relief, (3.) their concern to overlook physical disease in these patients, and (4.) their usage of psychotropic drugs with these patients. More experienced PCPs were better able to cope with the possibility of overlooking physical disease than those less experienced.

Conclusions

The PCPs in our survey answered that the obligation to rule out severe physical disease and the demand to relieve patients from symptoms belong to the most severe barriers for adequate treatment and diagnosis. Moreover, many physicians admitted to not knowing the appropriate treatment guidelines for these patients. Based on our results, raising awareness of guidelines and improving knowledge about the management of persistent somatic symptoms appear to be promising approaches for overcoming the barriers to diagnosis and treatment of persistent somatic symptoms in primary care.

Trial registration

German Clinical Trials Register (Deutschen Register Klinischer Studien, DRKS)

https://www.drks.de/drks_web/setLocale_EN.do

The date the study was registered: October 2^nd 2017

The date the first participant was enrolled: February 9^th 2018

DRKS-ID: DRKS00012942

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01397-w.

Helpful explanatory models for somatoform symptoms (HERMES): study protocol of a randomised mixed-methods pilot trial

INTRODUCTION

Persistent somatic symptoms (PSS) are common both in the general population and primary care. They are bothersome in terms of psychological and somatic symptom burden. Health professionals often struggle with communication, as there is a lack of scientifically supported explanatory models for PSS or a focus merely on somatic aspects of the complaints, which both frustrate patients' needs. The objective of the present study is therefore to develop a psychoeducational intervention based on a current evidence-based explanatory model, to examine its feasibility and form the basis for a large-scale randomised controlled trial.

METHODS AND ANALYSIS

In a randomised controlled mixed-methods pilot trial, 75 adult psychosomatic outpatients with PSS (duration of symptoms ≥6 months) and accompanying psychological (Somatic Symptom B-Criteria Scale total score ≥18) and somatic symptom burden (Patient Health Questionnaire-15 score >10) and no prior psychosomatic treatment will be eligible. Participants will be presented with either the explanatory model without (intervention group 1, n=25) or with elements of personalisation (intervention group 2, n=25). Participants in the control group (n=25) will receive information on current PSS guidelines. Participants will be blinded to group assignment and interventions will be shown on tablet computers at the outpatient clinic. After 1 month, qualitative follow-up telephone interviews will be conducted. As primary outcomes, mean changes in psychological and somatic symptom burden will quantitatively be compared between groups, respectively. Behavioural change mechanisms and feasibility of the three interventions will be evaluated using quantitative and qualitative measures.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the medical ethics board of the Hamburg Medical Chamber (PV5653). Results from this study will be published in peer-reviewed journals and presented at national and international conferences.

TRIAL REGISTRATION NUMBER

DRKS00018803.

SARS-CoV-2 Positive and Isolated at Home: Stress and Coping Depending on Psychological Burden

Objective: The SARS-CoV-2 pandemic has led to pronounced health changes, especially for those infected and psychologically burdened. This cross-sectional study examined the stress experience and coping strategies during home isolation of SARS-CoV-2 infected individuals and analyzed differences regarding psychological burden. Methods: SARS-CoV-2 infected respondents were recruited by telephone and completed an online survey during their home isolation. This questionnaire assessed sociodemographic aspects, somatic factors, psychological burden (depressive symptoms, anxiety, and somatic symptom disorder), perceived stress and coping behavior during the home isolation. Results: Out of 838 SARS-CoV-2 infected individuals during the study period, 648 were contacted and 224 home-isolated respondents were included in the study. Disgrace, social restrictions, job fear, health concerns, and infectiousness could be explored as stressors during the home isolation. Fifty-four percent experienced psychological burden. SARS-CoV-2 infected and home-isolated individuals with psychological burden perceived significant stressors more strongly (p < 0.001, r = 0.5) and coped significantly less (p < 0.001, r = 0.3) with their infection and home isolation compared to SARS-CoV-2 infected individuals without psychological burden. Conclusion: SARS-CoV-2 infected individuals with psychological burden experienced higher stressors and were unable to cope adaptively with home isolation. Therefore, a general and standardized screening procedure for psychological burden should be established. SARS-CoV-2 infected individuals with psychological burden should receive targeted support with professional help in the areas of stress experience and coping skills during their home isolation and beyond to avoid long-term consequences.

Validation of the Chinese Version of the Somatic Symptom Disorder-B Criteria Scale for Detecting DSM-5 Somatic Symptom Disorders: A Multicenter Study

OBJECTIVE

This study aimed to validate the Chinese version of the Somatic Symptom Disorder-B Criteria Scale (SSD-12) in an outpatient sample from Chinese general hospitals and to determine the diagnostic performance of the SSD-12 as a screening tool for somatic symptom disorder (SSD).

METHODS

The Chinese version of the SSD-12 was completed by 699 outpatients from nine general hospitals during a 16-month period (2016-2018). The SSD section of the Structured Clinical Interview for DSM Disorders, Fifth Edition, Research Version, was used to determine diagnostic accuracy (criterion validity). The construct validity of the SSD-12 was evaluated by examining correlations with the Whiteley Index-7, Patient Health Questionnaire-15, Patient Health Questionnaire-9, General Anxiety Disorder-7, World Health Organization Disability Assessment Schedule, and Medical Outcome Study 12-item Short Form Health Survey (SF-12).

RESULTS

The SSD-12 had excellent internal consistency in this sample (Cronbach α = .95). Confirmatory factor analyses replicated a three-factor structure that reflects the cognitive, affective, and behavioral aspects (Comparative Fit Index = 0.963, Tucker-Lewis Index = 0.952, root mean square error of approximation = 0.08, 90% confidence interval = 0.08-0.09), but was also consistent with a general one-factor model of the SSD-12 (Comparative Fit Index = 0.957, Tucker-Lewis Index = 0.948, root mean square error of approximation = 0.09, 90% confidence interval = 0.08-0.10). The optimal cutoff point for the Structured Clinical Interview for DSM Disorders-based diagnosis of SSD was 16 (sensitivity = 0.76, specificity = 0.80). The SSD-12 sum score was significantly associated with somatic symptom burden (Patient Health Questionnaire-15: r = 0.52, p < .001), health anxiety (Whiteley Index-7: r = 0.82, p < .001), depressive symptoms (Patient Health Questionnaire-9: r = 0.63, p < .001), general anxiety (General Anxiety Disorder-7: r = 0.64, p < .001), health-related quality of life (physical component score of SF-12: r = -0.49, p < .001; mental component score of SF-12: r = -0.61, p < .001), and health-related disabilities (World Health Organization Disability Assessment Schedule: r = 0.56, p < .001).

CONCLUSIONS

Initial assessment indicates that the Chinese version of the SSD-12 has sufficient reliability and validity to warrant further testing in both research and clinical settings.

Sensitivity to change and minimal clinically important difference of the 7-item Generalized Anxiety Disorder Questionnaire (GAD-7)

BACKGROUND

Effective treatment requires regular follow-up and monitoring of symptoms. We investigated sensitivity to change and minimal clinically important difference of the Generalized Anxiety Disorder Scale (GAD-7).

METHODS

This study included all participants from a multisite trial of chronic depression. Baseline and follow-up (12 and 48 weeks) data were used to assess treatment response. Effect sizes (ES) and standardized response means (SRM) of pre- and post-GAD-7 mean changes were calculated for subgroups of patients, who did or did not improve according to ratings in the Hamilton Rating Scale for Depression (HRSD-24).

RESULTS

N = 261 patients were included in the analyses. In the subgroup of patients who improved according to HRSD-24, GAD-7 scores were significantly lower after 12 weeks (t = -6.31, df = 120, p < .001; ES = -0.51, SRM = -0.57), and 48 weeks of treatment (t = -12.68, df = 141, p < .001; ES = -1.0, SRM = -1.7), when compared to admission. In the group who worsened, GAD-7 scores were significantly higher after 12 weeks (t = 2.96, df = 41, p = .005; ES = 0.30, SRM = 0.46), and increased after 48 weeks (t = 1.99, df = 21, p = .059; ES = 0.37, SRM = 0.43), when compared to baseline. The unchanged group showed no significant difference between baseline and follow-up. MCID was estimated 4 points on the GAD-7 total score.

LIMITATIONS

Confirmation of these findings and further investigation of the GAD-7 in populations and trials focusing on anxiety-specific treatment is highly recommended.

CONCLUSIONS

Results show that the GAD-7 is sensitive to detect change in psychopathology over the course of treatment.