Somatic Symptom Scale -8 in Major Depressive Disorder: A Psychometric Evaluation

Objective: Somatic symptom disorder (SSD) is characterized by somatic symptoms that are very distressing or cause considerable functional disability. SSD is associated with various medical and psychiatric conditions and imposes high costs on the patient's health care system. Therefore, diagnosis and treatment of SSD are crucial. The Somatic Symptom Scale-8 (SSS-8) is a valuable and brief self-report questionnaire to assess somatic symptom burden. The current study aimed to determine the psychometric properties of the Persian version of SSS-8 in depressed samples. Methods: Data were drawn from a clinical setting with individuals diagnosed with major depressive disorder (MDD, N = 122). convergent validity of SSS-8 was examined by assessing correlations with Hospital Anxiety and Depression Scale (HADS), Whiteley index (WI-14), and Somatic Symptom Disorder–B Criteria Scale (SSD-12) questionnaires. Results: Cronbach's alpha results confirmed the reliability of SSS-8. Reliability assessment with test-retest showed excellent reliability for scale. The CFA also approved the SSS-8 single-factor structure. The results of construct validity analysis of the questionnaire showed that SSS-8 has a positive and significant relationship with depression, anxiety, WI, and SSS-12. conclusion: The Persian version of the SSS-8 is an 8-item self-report questionnaire that health professionals and researchers can use to assess and screen somatic symptoms in individuals diagnosed with MDD.