Validation of the Psychometric Properties of Acceptance and Action Questionnaire-II in Clinical and Nonclinical Groups of Portuguese Population

This study explores the factor structure of the Acceptance and Action Questionnaire (AAQ-II) in both clinical and general normative groups. It also examines the factorial invariance of a one-factor proposed model in both groups. Data was collected from the overall database of a Portuguese Cognitive and Behavioral Research Center ( N= 687, 425 females; mean age= 36 years; SD = 11.33). ConArmatory Factor Analysis supported a one-factor structure with good internal consistencies and construct related validity. The one-factor solution was also supported with a second independent data set, which showed a conAgural, strict measurement and structural invariance of the one-factor solution proposed. Multigroup ConArmatory Factorial Analysis showed the conAgural invariance, weak measurement invariance and also structural invariance of the one-factor model of Acceptance and Action Questionnaire II across both groups under study. The one-factor model have both similar meanings and the same structure, but the measurement model in clinical and nonclinical groups was not the same. Toxic inAuences of experiencial avoidance as a core mechanism in the development and maintenance of several clinical disorders, may explain why the AAQ-II does not operate equivalently across clinical and nonclinical groups.