Poster 1

[P-1-01] Effectiveness of acceptance and commitment therapy on obsessive beliefs among patients with obsessive-compulsive disorder

*Seung Jae Lee^1,3, Sang Won Lee^2,3, Sung Man Chang^1,3 (1.Kyungpook National University Hospital(Korea), 2.Kyungpook National University Chilgok Hospital(Korea), 3.Kyungpook National University(Korea))

Keywords:

Acceptance commitment therapy,metacognitive therapy,obsessive belief,obsessive-compulsive disorder

Although theoretically distinct, both acceptance and commitment therapy (ACT) and metacognitive therapy (MCT) focus on the relationship with inner experiences—specifically, cognitive fusion and fused object mode—that drive unhelpful coping strategies, such as experiential avoidance, obsessive rumination and compulsions, and, with mindfulness as a core therapeutic factor. In this context, ACT’s therapeutic effects on obsessive-compulsive disorder (OCD) are presumably reflected in the Obsessive Beliefs Questionnaire (OBQ), which incorporates significant metacognitive factors. However, most studies have investigated ACT’s effects on obsessive-compulsive (OC) symptoms rather than on obsessive beliefs. Consequently, this study examined the relationship between ACT process measures—namely, Acceptance and Action Questionnaire-II (AAQ-II) and Cognitive Fusion Questionnaire (CFQ)—and the OBQ following an eight-week group-format ACT (GACT) intervention among patients with OCD (GACT group, N = 37; wait-list control group, N = 42). Significant reductions were observed in AAQ-II, CFQ, and OBQ scores after treatment. Changes in AAQ-II and CFQ (particularly in the former) were significantly associated with changes in the OBQ total and subscale scores. These measures accounted for 26% and 12% of the variance in the OBQ total score and OCD symptom scores, respectively. Among OBQ subscales, changes in AAQ-II and CFQ best accounted for the variance of perfectionism and intolerance of uncertainty (OBQ-PIU), followed by importance and control of thoughts (OBQ-ICT). In conclusion, improvements in ACT process measures through GACT explained obsessive beliefs—particularly OBQ-PIU and OBQ-ICT—better than OCD symptoms, thus highlighting the clinical significance of obsessive beliefs in ACT treatment for OCD.