Italian Version of the Acceptance and Action Questionnaire-II (AAQ-II): Dimensionality, Reliability, Convergent and Criterion Validity

This study focused on the validation of the Italian version of the Acceptance and Action Questionnaire-II (AAQ-II, Bond et al. Behavior Therapy 42:676-688, 2011). This measure was developed to address the need for an improved measure of psychological inflexibility. The participants were 255 adults (77 males and 178 females, mean age of 31.9 years, SD = 13.7) from the general population. The results of Principal Axis Factor analyses supported a unidimensional structure of AAQ-II scores. The one-factor solution accounted for 42 % of the variance. Internal consistency was high (.83), and test-retest reliability over a 12-month period was modest (.61). Higher AAQ-II scores significantly related to anxiety and depression, and to lower psychological well-being, supporting the concurrent validity of the scale. Correlations with measures of conceptually related constructs also supported the convergent validity of the scale. Furthermore, psychological inflexibility significantly predicted important outcome measures beyond conceptually related constructs. The results of this study suggest that the Italian version of the AAQ-II is a reliable and valid measure of psychological inflexibility, and that the 7-item version of the scale features improved psychometric properties over previous versions of the questionnaire.