Worry, Rumination, and Metacognitive Beliefs in Adolescents with Obesity Associated with Binge Eating Disorder (BED) vs. Age-Matched Adolescents with Essential Obesity: A Cross-Sectional Study

Background/Objectives: The study aimed to investigate the presence of worry, rumination, and metacognitive beliefs in adolescents with maladaptive eating behaviours. Methods: The study involved 37 adolescents (10 males, 27 females, mean age ± SD: 15.4 ± 1.53 years) with obesity (Body Mass Index, BMI > 97th centile) associated with binge eating disorder (BED) (BES score ≥ 17) and 30 age-matched adolescents (13 males, 17 females, mean age ± SD: 15.2 ± 1.98 years) with essential obesity (i.e., without BED, BES score < 17). Participants completed self-report questionnaires—Penn State Worry Questionnaire (PSWQ), Ruminative Response Scale (RRS), Anger Rumination Scale (ARS), and Metacognitions Questionnaire for Children (MCQ-C)—to assess binge eating, worry, rumination, and metacognitive beliefs, respectively. Results: Patients with obesity and BED showed higher scores on the PSWQ (p = 0.006), RRS (p < 0.001), ARS (p < 0.001), negative Metaworry (p = 0.011), and total MCQ-C (p = 0.027) than those with essential obesity, with a medium-to-large effect size, indicating that the differences between subgroups were meaningful. Conclusions: Our findings highlight that BMI alone is not associated with metacognitive processes and beliefs. The presence of BED in adolescents with obesity is linked to increased levels of worry, rumination, and maladaptive metacognitive beliefs, in comparison with age-matched adolescents with essential obesity. The results of the study underline the need for different psychological approaches in these clinical conditions going forward.