Cultural Adaptation into Spanish of the Generalized Anxiety Disorder Scale - 7 (GAD-7) Scale

Abstract

Purpose:To carry out cultural adaptation and validation into Spanish of the 7-items self-administered GAD-7 scale; a tool to identify probable patients with Generalized Anxiety Disorder (GAD).Material and methods:The adaptation, conducted by an eight-expert panel, was performed by means of a conceptual equivalence process, including forward and backward translations in duplicate to the original language. The content validity was assessed by inter-ratter-agreement (item-goal congruence index of Rovinelli-Hambleton). The adapted version was administered to patients with GAD according to DSM IV criteria and their respective controls, matched by age and sex, who were recruited at random in Mental Health and Primary Care centres to verify scale feasibility and potential understanding problems.Results:The inter-ratter reliability confirmed the correct inclusion of items in the corresponding dimension of GAD. The study sample consisted of 8 patients with GAD and 8 controls (62.5% male), mean age 50.38 years (SD=16.76). The average time to completion was 2’30”. No items of the scale were left blank. Floor and ceiling effects were negligible. No patients with GAD had to be assisted to fill in the questionnaire. All the items, except item 5 (p=0,105), showed statistically significant differences among groups (p< 0.05).Conclusion:After the adaptation process, a Spanish version of the GAD-7 scale was obtained, confirming its content validity, pertinence and adequacy of items in the Spanish cultural context. The brief time to completion precluded a fast and easy self-administration in the routine medical practice to promptly detect probable cases of GAD.