AAQ-II

The Acceptance and Action Questionnaire-II (AAQ-II) is a 7-item self-report measure of psychological inflexibility and experiential avoidance, two core constructs in Acceptance and Commitment Therapy (ACT). Items assess the tendency to avoid unwanted internal experiences (thoughts, emotions, sensations) and the degree to which this avoidance interferes with living a valued life. Each item is rated 1–7, with total scores from 7 to 49 and higher scores indicating greater psychological inflexibility. The AAQ-II is used in psychedelic research to test whether psychedelic experiences increase psychological flexibility — a transdiagnostic mechanism hypothesized to underlie the broad therapeutic effects of psychedelics across depression, addiction, and anxiety. Studies have shown that psilocybin reduces AAQ-II scores, suggesting increased acceptance and willingness to engage with difficult internal experiences. The AAQ-II has adequate reliability (α = 0.84) and strong convergent validity with measures of depression, anxiety, and quality of life.