Metabeliefs about worry, cognitive fusion, and acceptance: associations and mediations analysis

Background Although metacognitive therapy (MCT) and acceptance and commitment therapy (ACT) are grounded in different theoretical frameworks, both target repetitive negative thinking (RNT) processes, such as worry and rumination, and share a focus on fostering psychological flexibility and reducing experiential avoidance. However, no integrated theoretical model currently exists to combine their potential strengths. Recent research highlights the importance of metacognitive beliefs and acceptance-related processes in maintaining maladaptive RNT. Objective This study aimed to explore metacognitive and acceptance-based variables in relation to RNT. Methods The sample consisted of 149 people (116 females), aged between 18 and 71 (M = 34.7; SD = 14.9) who answered the following questionnaires: PSWQ, The AAQ-II, The CFQ, The VQ, MCQ-30 and TCQ. Results The mediation analysis reveals that cognitive fusion significantly mediated the relationship between metacognitive beliefs and worry, whereas acceptance had a weaker mediating effect. Conclusion Beliefs about the uncontrollability of worry appear to play a pivotal role in sustaining worry, primarily through their influence on cognitive fusion. These findings provide preliminary support for conceptual overlaps between MCT and ACT in addressing RNT. However, as this is an exploratory and cross-sectional study, conclusions about treatment mechanisms should be drawn cautiously, and future longitudinal and experimental studies are needed to strengthen these insights.