Factor Structure of Persian General Health Questionnaire-28 in Dermatologic Patients: A Confirmatory Factor Analysis

Introduction: GHQ-28 is a screening instrument for evaluating psychiatric symptoms in vast groups of individuals. This study is the first attempt to examine the factor structure of the GHQ-28 in Iranian people. Methods: Three hundred and thirty six inpatients and outpatients who suffered from skin disease referred to Razi hospital in Tehran fully completed the GHQ-28 questionnaire. Factor structure of GHQ28 was assessed using confirmatory factor analysis. The comparison among four hypothesized models: orthogonal 4-factor, oblique 4-factor, Tau-equivalence oblique 4-factor and single second-order was done and the best model fitted to the data was obtained. The data was analyzed using SAS software. Results: Our findings showed that the oblique 4-factor and the single second-order models had the best fit based on fit indices; however the oblique 4-factor model was the best choice due to the smaller AIC and clearer interpretation. Conclusion: Assuming oblique factor model is a better realization of the practical situation using GHQ-28 among the dermatologic patients and show the stability and validity of the instrument in this population as a diagnostic tool.