Psychometric properties of the Spanish version of the screening scale for DSM-IV Generalized Anxiety Disorder of Carroll and Davidson

Introduction. The aim was to validate the Spanish version of the screening scale for DSM-IV General Anxiety Disorder of Carroll and Davidson for use in research and clinical practice in Spain for screening and assessing specific anxiety symptoms of patients with Generalized Anxiety Disorder (GAD). Methods. Observational, prospective, multisite, study comparing between patients with DSM-IV diagnosis of GAD (group A), starting or switching treatment (group A1) or stable patients (group A2), followed-up for 6 months (group A1) or 2 weeks (group A2) versus healthy control subjects (group B), assessed in a single visit. Results. Among 223 valuable subjects the scale showed: a) adequate feasibility with a mean time of administration: 6,53 and 4,49 minutes (DT: 5.48 and 3.56) in groups A and 13, and percentage of patients without response<5%; b) adequate reliability (Kuder-Richardson coefficient: 0.85 and 0.79 in groups A1 and A2, and CCl coefficient: 0.89 in group A2); c) adequate validity, showing capability for discriminating between patients and controls, with area under curve AUC: 0.9713 (IC 95%: 0.9510-0.9917), and obtaining a high correlation with HARS (r=0.88) and ICG-G (r=0.87) scales, y d) adequate sensitivity to clinical changes from start and end of treatment (SES: -1.6. -3.1 and -3.8 after 1, 3 and 6 months), spite of the high percentage of patients with highest score in group A1 (38.6%). Conclusion. The Spanish version of the screening scale for DSM-IV GAD showed adequate psychometric properties for use in research and clinical practice in Spain as well as an screening as evaluative measure for patients with GAD, spite of the ceiling effect showed in severe patients.