Introduction: This study illustrates how mindfulness and acceptance-based intervention (MABI) can change metacognitions and executive functions among individuals with anxiety disorders. Methods: Forty-five Iranian individuals (mean [SD] age, 24.60 [4.94] years; 51.1 % female) with comorbid anxiety disorders participated in a randomized, waitlist-controlled trial of weekly group sessions of either MABI or waitlist control (WLC). Primary and process of change outcomes were assessed at baseline, post-intervention, and 1-month follow-up. Results: Significant changes were observed over time on anxiety symptoms (Cohen d = 1.04, 95% CI [0.40±1.65]), as well as on metacognitive beliefs (Cohen d = 1.04, 95% CI [0.40±1.64]), executive functions (Cohen d = 0.91, 95% CI [0.28±1.51]), and mindfulness facets (Cohen d = 0.97, 95% CI [0.34±1.58]), in favor of MABI over WLC. Conclusions: Overall, findings add to the knowledge in the field and provide cross-cultural evidence in support of MABIs as interventions that target anxiety symptoms, metacognitive beliefs and executive functions in a non-Western culture.
