Investigating the Factor Structure of Somatic Symptom Disorder Questionnaire in the Sample of Psychiatric Patients in Isfahan, Iran

Aim and Background: Somatic symptom is one of the prevalent complaints in patients with psychiatric disorders and in Diagnostic and Statistical Manual of Mental Disorders-5th Edition (DSM-5) is mentioned as somatic symptom disorder (SSD). In order to assess somatic complaints, validated scales are required. The aim of the present study was preparation of Persian version and determination of factor structure (as one of the psychometric properties) of Screening for Somatoform Symptoms-7 (SOMS-7) scale in Iranian samples. Methods and Materials: This psychometric study was conducted in Psychosomatic Research Center of Isfahan University of Medical Sciences, Isfahan, Iran, and included 100 patients with anxiety/mood disorders. All participants were asked to complete SOMS-7 and Patient Health Questionnaire (PHQ). Validity was confirmed by correlational method, and factor analysis and external and internal reliability were confirmed by Cronbach's alpha coefficient and re-test method. Factor analysis was performed by exploratory and confirmatory method. Data were analysed via SPSS software. Findings: Internal consistency of SOMS-7 was obtained 0.92 using Cronbach's alpha and reliability was obtained 0.70 via re-test method in two weeks interval. Factor analysis showed an appropriate two-factor structure in patients. The correlation of these two factors with somatic scale of PHQ was obtained 0.51 and 0.59, respectively, and revealed the construction validity as well as convergent validity. Findings indicate that Persian version of SOMS-7 has suitable reliability and validity for assessment of SSD and also evaluation of treatment effects in these patients.