KMAN Publication Inc. (KMANPUB) KMAN Counseling & Psychology Nexus 3041-9026 In Press 2027 01 01 Effectiveness of an Integrated Cognitive Control–Metacognitive Intervention on Obsessive–Compulsive Symptoms: The Roles of Executive Function, Inhibitory Control, Metacognition, and Neurophysiological Indices Effectiveness of an Integrated Cognitive Control–Metacognitive Intervention on Obsessive–Compulsive Symptoms: The Roles of Executive Function, Inhibitory Control, Metacognition, and Neurophysiological Indices 1 17 EN Journal Article 2026 07 30 <p>This study aimed to evaluate the effectiveness of an integrated cognitive control–metacognitive intervention (ICCMI) for reducing obsessive–compulsive symptoms and improving executive function, inhibitory control, metacognitive beliefs, and neurophysiological indices in adults with obsessive–compulsive disorder (OCD). An assessor-blinded, parallel-group randomized controlled trial was conducted with 80 adults aged 18–55 years who met DSM-5-TR criteria for OCD and had Yale–Brown Obsessive–Compulsive Scale (Y-BOCS) scores ≥16. Participants were randomly assigned to ICCMI or a wait-list control group in a 1:1 ratio. The intervention comprised eight weekly 120-minute group sessions integrating metacognitive therapy, attention regulation, goal-management strategies, response-inhibition training, and adaptive error monitoring. Assessments were conducted at baseline, post-treatment, and 8-week follow-up; EEG/ERP measures were obtained at baseline and post-treatment. Outcomes included Y-BOCS, Metacognitions Questionnaire-30, an executive-function composite, stop-signal reaction time (SSRT), Stroop interference, and NoGo-N2, NoGo-P3, ERN, and Pe amplitudes. Generalized estimating equations, baseline-adjusted EEG models, Hedges’ g, and exploratory bootstrap mediation analyses were used. Significant group × time effects favored ICCMI for Y-BOCS at post-treatment (B = −8.92, SE = 0.47, p &lt; .001) and follow-up (B = −10.16, SE = 0.53, p &lt; .001). Significant improvements were also observed for MCQ-30, executive functioning, SSRT, and Stroop interference (all p &lt; .001). Baseline-adjusted EEG analyses showed significant effects for NoGo-N2 (+1.14 µV), NoGo-P3 (+1.43 µV), and Pe (+0.57 µV), all p &lt; .001, whereas ERN change was nonsignificant (p = .062). Mediation analyses identified significant indirect effects through metacognitive belief change (0.53, 95% CI [0.16, 0.98]) and SSRT improvement (0.41, 95% CI [0.19, 0.69]). ICCMI produced substantial and sustained reductions in OCD symptoms while improving metacognitive, executive, inhibitory, and selected neurophysiological processes, with metacognitive change and response inhibition emerging as particularly important candidate mechanisms of therapeutic improvement.</p> https://journals.kmanpub.com/index.php/psychnexus/article/download/6483/12093