Abstract
OBJECTIVE: Modifying cognitive distortions, or thinking errors, is crucial in eating disorders (ED) treatment. To address the lack of a personalized measure for ED cognitions, the Thought Inventory was developed. The study aimed to establish its feasibility and validity, identify thinking error contents and types, examine changes in belief of irrational thoughts, and investigate associations with change in ED symptoms. Hypotheses, procedure, and planned analyses were pre-registered to ensure transparency. METHODS: Participants (N = 55) completed the Thought Inventory, the Eating Disorder Examination Questionnaire, the Eating Pathology Symptom Inventory, the Frost Multidimensional Perfectionism Scale, the Beck Depression Inventory, and the Penn State Worry Questionnaire at pre-and post-ten weeks of treatment. Using the Thought Inventory, participants collaborated with study therapists to identify ED-related thinking errors and rate the degree of belief in these thoughts on a scale of 0 to 100 %. RESULTS: Cognitions primarily contained self-judgments, food rules, and concern over shape, while catastrophizing/fortune telling, emotional reasoning, and should/must statements were the most common types of thinking errors. Belief in cognitions significantly decreased over treatment and change in thought belief was positively associated with change in ED symptoms. CONCLUSION: The Thought Inventory shows promise as a personalized measure. Future research should explore whether ED cognitions, assessed in this manner, are a mechanism of change in ED treatment.