Abstract
Evaluating the increasing somatic symptoms in adolescents and youth is essential in epidemiological surveillance. This study aims to investigate the psychometric properties of the Somatic Symptom Scale-8 (SSS-8), a brief instrument assessing somatic symptoms in Chinese youth and adolescents using both Classical Test Theory and Rasch Measurement Theory using two independent samples (N = 398 and 16,231). Internal consistency was assessed by Cronbach’s alpha and McDonald’s omega coefficients. Construct validity, and convergent and discriminant validity were examined by Spearman’s correlations of the items or scale with external instruments and internal symptom domains. Structural validity was evaluated using confirmatory factor analysis (CFA). Rasch analysis was performed including rating scale functioning, unidimensionality, item difficulties and person abilities, item and person reliabilities and separation, and differential item functioning (DIF). The Cronbach’s alpha and McDonald’s omega were both 0.82 (Sample 1) and 0.92 (Sample 2). The SSS-8 score correlated with two subscales of depression and anxiety (r = 0.56 and 0.62, p < 0.001), and positive mental health (r = -0.31, p < 0.001). All items strongly correlated with their own domains (r > 0.70). The CFA confirmed the high-order factor model and found partial invariance across gender. In Rasch analysis, step calibrations and category measures indicated adequate category functioning. The unidimensionality was proved as no second dimension occurred. The SSS-8 was found able to separate the participants into two levels of somatic symptoms. No significant DIF was detected across gender. The findings supported the use of the SSS-8 to assess somatic symptoms in this group.
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Data availability
The datasets analysed during the current study are not publicly available due to the restrictions applied to the availability of these data by the school and university administrators involved in the study. Data are however available from the corresponding author upon reasonable request and with permission of all the school and university administrators.
References
Anselmi, P., Colledani, D., & Robusto, E. (2019). A comparison of classical and modern measures of internal consistency. Frontiers in Psychology, 10, 2714. https://doi.org/10.3389/fpsyg.2019.02714
Berg, N., Nummi, T., Bean, C. G., Westerlund, H., Virtanen, P., & Hammarström, A. (2022). Risk factors in adolescence as predictors of trajectories of somatic symptoms over 27 years. European Journal of Public Health, 32(5), 696–702. https://doi.org/10.1093/eurpub/ckac081
Bond, T. M., & Fox, C. G. (2007). Applying the Rasch model: Fundamental measurement in the human sciences. Lawrence Erlbaum.
Boone, W. J., Staver, J. R., & Yale, M. S. (2014). Rasch analysis in the human sciences. Springer.
Chen, F. F. (2007). Sensitivity of goodness of fit indexes to lack of measurement invariance. Structural Equation Modeling-a Multidisciplinary Journal, 14(3), 464–504. https://doi.org/10.1080/10705510701301834
Chen, F. F., Sousa, K. H., & West, S. G. (2005). Teacher’s corner: Testing measurement invariance of second-order factor models. Structural Equation Modeling-a Multidisciplinary Journal, 12(3), 471–492. https://doi.org/10.1207/s15328007sem1203_7
Cohen, J. (1992). A power primer. Psychological Bulletin, 112(1), 155–159. https://doi.org/10.1037/0033-2909.112.1.155
Gierk, B., Kohlmann, S., Kroenke, K., Spangenberg, L., Zenger, M., Brähler, E., & Löwe, B. (2014). The somatic symptom scale–8 (SSS-8): A brief measure of somatic symptom burden. JAMA Internal Medicine, 174(3), 399–407. https://doi.org/10.1001/jamainternmed.2013.12179
Gierk, B., Kohlmann, S., Toussaint, A., Wahl, I., Brünahl, C. A., Murray, A. M., & Löwe, B. (2015). Assessing somatic symptom burden: A psychometric comparison of the patient health questionnaire-15 (PHQ-15) and the somatic symptom scale-8 (SSS-8). Journal of Psychosomatic Research, 78(4), 352–355. https://doi.org/10.1016/j.jpsychores.2014.11.006
Gothwal, V. K., Wright, T. A., Lamoureux, E. L., & Pesudovs, K. (2009). Rasch analysis of visual function and quality of life questionnaires. Optometry and Vision Science, 86(10), 1160–1168. https://doi.org/10.1097/OPX.0b013e3181bab10c
Guo, C., Tomson, G., Guo, J. Z., Li, X. Y., Keller, C., & Söderqvist, F. (2015). Psychometric evaluation of the Mental Health Continuum-Short Form (MHC-SF) in Chinese adolescents - a methodological study. Health and Quality of Life Outcomes, 13, 198. https://doi.org/10.1186/s12955-015-0394-2
Hadžibajramović, E., Schaufeli, W., & De Witte, H. (2020). A Rasch analysis of the burnout assessment tool (BAT). PLoS ONE, 15(11), e0242241. https://doi.org/10.1371/journal.pone.0242241
Hagquist, C., Bruce, M., & Gustavsson, J. P. (2009). Using the Rasch model in nursing research: An introduction and illustrative example. International Journal of Nursing Studies, 46(3), 380–393. https://doi.org/10.1016/j.ijnurstu.2008.10.007
Henry, J. D., & Crawford, J. R. (2005). The short-form version of the depression anxiety stress scales (DASS-21): Construct validity and normative data in a large non-clinical sample. British Journal of Clinical Psychology, 44(2), 227–239. https://doi.org/10.1348/014466505X29657
Hu, L. T., & Bentler, P. M. (1999). Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives. Structural Equation Modeling-a Multidisciplinary Journal, 6(1), 1–55. https://doi.org/10.1080/10705519909540118
Keyes, C. L. M. (2002). The mental health continuum: From languishing to flourishing in life. Journal of Health and Social Behavior, 43(2), 207–222. https://doi.org/10.2307/3090197
Kitselaar, W. M., van der Vaart, R., Perschl, J., Numans, M. E., & Evers, A. W. M. (2023). Predictors of persistent somatic symptoms in the general population: A systematic review of Cohort studies. Psychosomatic Medicine, 85(1), 71–78. https://doi.org/10.1097/PSY.0000000000001145
Kliem, S., Krieg, Y., Beller, J., Brähler, E., & Baier, D. (2021). Psychometric properties of the somatic symptom scale 8 (SSS-8) in a representative sample of German adolescents. Journal of Psychosomatic Research, 149, 110593. https://doi.org/10.1016/j.jpsychores.2021.110593
Kline, P. (2000). The handbook of psychological testing (2nd ed.). Routledge.
Kozlowska, K. (2013). Functional somatic symptoms in childhood and adolescence. Current Opinion in Psychiatry, 26(5), 485–492. https://doi.org/10.1097/YCO.0b013e3283642ca0
Kroenke, K., & Mangelsdorff, A. D. (1989). Common symptoms in ambulatory care: Incidence, evaluation, therapy, and outcome. American Journal of Medicine, 86(3), 262–266. https://doi.org/10.1016/0002-9343(89)90293-3
Li, T., Wei, J., Fritzsche, K., Toussaint, A. C., Zhang, L., Zhang, Y., Chen, H., Wu, H., Ma, X., Li, W., Ren, J., Lu, W., & Leonhart, R. (2022). Validation of the Chinese version of the somatic symptom scale-8 in patients from tertiary hospitals in China. Frontiers in Psychiatry, 13, 940206. https://doi.org/10.3389/fpsyt.2022.940206
Linacre, J. M. (2006). Data variance explained by measures. Rasch Measurement Transactions, 20, 1045.
Linacre, J. M. (2011). A user’s guide to Winsteps/Ministep rasch-model computer program. Winsteps.com.
Linacre, J. M. (2022). Reliability and separation of measures. Retrieved August 25, 2022, from https://www.winsteps.com/winman/reliability.htm
Linacre, J. M. (1999). Investigating rating scale category utility. Journal of Outcome Measurement, 3(2), 103–122.
Low, G. D. (1988). The semantics of questionnaire rating scales. Evaluation & Research in Education, 2(2), 69–79. https://doi.org/10.1080/09500798809533241
Löwe, B., Levenson, J., Depping, M., Hüsing, P., Kohlmann, S., Lehmann, M., Shedden-Mora, M., Toussaint, A., Uhlenbusch, N., & Weigel, A. (2022). Somatic symptom disorder: A scoping review on the empirical evidence of a new diagnosis. Psychological Medicine, 52(4), 632–648. https://doi.org/10.1017/S0033291721004177
Malec, J. F., Torsher, L. C., Dunn, W. F., Wiegmann, D. A., Arnold, J. J., Brown, D. A., & Phatak, V. (2007). The Mayo high performance teamwork scale: Reliability and validity for evaluating key crew resource management skills. Simulation in Healthcare, 2(1), 4–10. https://doi.org/10.1097/SIH.0b013e31802b68ee
Matsudaira, K., Oka, H., Kawaguchi, M., Murakami, M., Fukudo, S., Hashizume, M., & Löwe, B. (2017). Development of a Japanese version of the somatic symptom scale-8: Psychometric validity and internal consistency. General Hospital Psychiatry, 45, 7–11. https://doi.org/10.1016/j.genhosppsych.2016.12.002
Mayou, R., & Farmer, A. (2002). Functional somatic symptoms and syndromes. BMJ, 325, 265–268. https://doi.org/10.1136/bmj.325.7358.265
McNeish, D. (2018). Thanks coefficient alpha, we’ll take it from here. Psychological Methods, 23(3), 412–433. https://doi.org/10.1037/met0000144
Parrish, C., Haines, R. T., Stewart, D., Szabo, M., Caradec, J., Ziegfeld, S., Reynolds, E., & Ostrander, R. (2020). Assessing child quality of life impairments following pediatric burn injuries: Rasch analysis of the children’s dermatology life quality index. Quality of Life Research, 29(4), 1083–1091. https://doi.org/10.1007/s11136-019-02380-w
Petrelis, M., & Domeyer, P. R. (2021). Translation and validation of the Greek version of the somatic symptom scale-8 (SSS-8) in patients with chronic low back pain. Disability and Rehabilitation, 44(16), 4467–4473. https://doi.org/10.1080/09638288.2021.1900415
Smith, A. B., Rush, R., Fallowfield, L. J., Velikova, G., & Sharpe, M. (2008). Rasch fit statistics and sample size considerations for polytomous data. BMC Medical Research Methodology, 8(1), 33. https://doi.org/10.1186/1471-2288-8-33
Steiger, J. H. (1990). Structural model evaluation and modification - an interval estimation approach. Multivariate Behavioral Research, 25(2), 173–180. https://doi.org/10.1207/s15327906mbr2502_4
Stolt, M., Kottorp, A., & Suhonen, R. (2022). The use and quality of reporting of Rasch analysis in nursing research: A methodological scoping review. International Journal of Nursing Studies, 132, 104244. https://doi.org/10.1016/j.ijnurstu.2022.104244
Sullivan, G. M., & Feinn, R. (2012). Using effect size-or why the P value is not enough. Journal of Graduate Medical Education, 4(3), 279–282. https://doi.org/10.4300/jgme-d-12-00156.1
Tennant, A., & Conaghan, P. G. (2007). The Rasch measurement model in rheumatology: What is it and why use it? When should it be applied, and what should one look for in a Rasch paper? Arthritis Care & Research, 57(8), 1358–1362. https://doi.org/10.1002/art.23108
Tennant, A., & Pallant, J. F. (2006). Unidimensionality matters! (a tale of two Smiths?). Rasch Measurement Transactions, 20(1), 1048–1051.
Toussaint, A., Kroenke, K., Baye, F., & Lourens, S. (2017). Comparing the patient health questionnaire-15 and the somatic symptom scale-8 as measures of somatic symptom burden. Journal of Psychosomatic Research, 101, 44–50. https://doi.org/10.1016/j.jpsychores.2017.08.002
Wang, K., Shi, H. S., Geng, F. L., Zou, L. Q., Tan, S. P., Wang, Y., Neumann, D. L., Shum, D. H. K., & Chan, R. C. K. (2016). Cross-cultural validation of the depression anxiety stress Scale–21 in China. Psychological Assessment, 28(5), e88–e100. https://doi.org/10.1037/pas0000207
Wolf, E. J., Harrington, K. M., Clark, S. L., & Miller, M. W. (2013). Sample size requirements for structural equation models: An evaluation of power, bias, and solution propriety. Educational and Psychological Measurement, 76(6), 913–934. https://doi.org/10.1177/0013164413495237
Wongpakaran, N., Wongpakaran, T., Pinyopornpanish, M., Simcharoen, S., Suradom, C., Varnado, P., & Kuntawong, P. (2020). Development and validation of a 6-item revised UCLA Loneliness Scale (RULS-6) using Rasch analysis. British Journal of Health Psychology, 25(2), 233–256. https://doi.org/10.1111/bjhp.12404
Wright, B. D. (1996). Reliability and separation. Rasch Measurement Transactions, 9(4), 472.
Wright, B. D., & Linacre, J. M. (1989). Observations are always ordinal; measurements, however, must be interval. Archives of Physical Medicine and Rehabilitation, 70, 857–860.
Yang, C. M., Hwang, K. S., Lee, S. Y., Seo, J. S., & Jang, S. H. (2020). Reliability and validity of the Korean version of somatic symptom scale-8. Psychiatry Investigation, 17(8), 814–821. https://doi.org/10.30773/pi.2020.0112
Yuan, C., Yong, G., Wang, X., Xie, T., Wang, C., Yuan, Y., & He, G. (2020). Developing the patient health questionnaire-8 for a greater impact on the quality of life of patients with functional dyspepsia compared to somatic symptom scale-8. BMC Gastroenterology, 20(1), 359. https://doi.org/10.1186/s12876-020-01508-4
Zijlema, W. L., Stolk, R. P., Löwe, B., Rief, W., White, P. D., & Rosmalen, J. G. M. (2013). How to assess common somatic symptoms in large-scale studies: A systematic review of questionnaires. Journal of Psychosomatic Research, 74(6), 459–468. https://doi.org/10.1016/j.jpsychores.2013.03.093
Acknowledgements
The authors would like to gratefully acknowledge Professor Bernd Löwe (University Medical Center Hamburg-Eppendorf, Germany) for the permission to use and validate the Somatic Symptom Scale-8 in the current study. The authors would also like to thank all the participants for their cooperation in the study.
Funding
This work was supported by the East China University of Science and Technology Cooperative Research Fund (grant no. YE0130513) and Fundamental Research Funds for the Central Universities (Humanities and Social Sciences), China (grant no. JKE01212204).
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All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Approval was granted by the Ethics Committee, East China University of Science and Technology (ECUST-2022-059).
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Wu, C., Wang, W., Ji, H. et al. Assessing Somatic Symptom Scale-8 (SSS-8) in Chinese youth and adolescents: using Classical Test Theory and Rasch Measurement Theory. Curr Psychol 43, 18168–18182 (2024). https://doi.org/10.1007/s12144-024-05624-2
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DOI: https://doi.org/10.1007/s12144-024-05624-2