Abstract Aim Cost and probability biases are known to predict improvements in symptoms of social anxiety disorder (SAD). This study developed a high‐intensity mindfulness and cognitive behavioral group therapy (M‐CBT) program—comprising mindfulness training, psychoeducation, cognitive restructuring, exposure exercises, and group sharing—designed to reduce these biases. The intervention was delivered in a group format, and its preliminary efficacy in patients with SAD was evaluated in a pilot single‐arm trial. Methods Patients ( N = 10) diagnosed with SAD through a structured clinical interview participated in an eight‐session M‐CBT program. They completed a set of questionnaires assessing SAD symptoms, cost and probability biases, fear of negative evaluation, self‐focused attention, depressive symptoms, subjective happiness, dispositional mindfulness, cognitive reappraisal, and suppression at pre‐intervention, mid‐intervention, post‐intervention, and follow‐up. Results Analyses using linear mixed‐effects models revealed that high‐intensity M‐CBT produced improvements in SAD symptoms, cost and probability biases, depressive symptoms, subjective happiness, dispositional mindfulness, and cognitive reappraisal ( p < 0.05). The intervention also yielded significant reductions in cost and probability biases from pre‐ to post‐treatment and at follow‐up, with large effect sizes (cost bias: Cohen's d = 0.85–1.27; probability bias: d = 1.07–2.42). In contrast, the effect sizes for SAD symptoms were moderate ( d = 0.57–0.67). Conclusions These findings suggest that high‐intensity M‐CBT can alleviate SAD symptoms and reduce cost and probability biases. Moreover, delivering M‐CBT in a high‐intensity format appears to be effective for individuals with SAD. Future randomized‐controlled trials are warranted to more rigorously confirm these effects.
Shirotsuki et al. (Mon,) studied this question.