Psychometric properties of Generalized Anxiety Disorder-7 during COVID-19: item response theory analysis

Abstract This study evaluated the psychometric properties of the Generalized Anxiety Disorder Scale 7-item in a Brazilian sample during the COVID-19 pandemic using item response theory. The graded response model was applied to estimate discrimination and difficulty parameters and generate the item characteristic curve, item information curve, and test information curve. Differential Item Functioning (DIF) was analyzed by gender, and anxiety and theta levels were assessed. The sample included 10,069 participants, with a mean age of 36 years (standard deviation=13.67). The scale exhibited satisfactory performance, with items associated with worry being particularly informative. Item 5 was highlighted for identifying severe anxiety symptoms. No differential item functioning was observed between genders. Collectively, these results reinforce the reliability of the Generalized Anxiety Disorder 7-item as an effective tool for assessing anxiety symptoms.