Supplementary Material for: A large-group one-day RCT investigating the effectiveness of four different strategies to promote the outcome of exposure therapy in 519 patients with phobic fear of flying

Despite its status as the gold standard for treating fear and anxiety, exposure therapy leaves room for optimization. Clarifying and testing the clinical relevance of proposed mechanisms may enhance outcomes. This randomized controlled trial (DRKS00031220) examined the effects of four psychological strategies aimed at facilitating exposure outcomes in individuals with clinically significant fear of flying due to Specific Phobia or Agoraphobia (N = 519). All participants underwent a standardized large-group one-session treatment (LG-OST) including psychoeducation, debriefing, and an in vivo exposure flight. Participants were randomized to one of four conditions targeting distinct mechanisms: peer support (SUPPORT), self-efficacy (SELF-EFFIC), expectancy violation (EXPECT), or coping with bodily fear symptoms (COPE). These mechanisms were reinforced prior and during paralleled exposure flights, conducted in separate aircraft per condition. Across all conditions, LG-OST led to substantial symptom reduction short- and long-term. Fear ratings halved, over 50 % flew again within the 6-month follow-up interval, and ~70 % no longer met diagnostic criteria. However, no condition yielded superior outcomes. While manipulation checks confirmed partial activation of target mechanisms (e.g., greater perceived peer support in SUPPORT, increased use of breathing techniques in COPE), these effects did not translate into differential clinical benefits. Findings support the efficacy and scalability of LG-OST, while suggesting that tailoring preparatory strategies to specific mechanisms may have limited added value. They also highlight the need to advance mechanistic research to better understand the intertwined processes underlying exposure success. Future work should focus on improving accessibility and sustaining long-term gains.尽管暴露疗法（exposure therapy）是治疗恐惧与焦虑的金标准，但其仍存在优化空间。明确并检验所提出机制的临床相关性，或可提升治疗效果。这项编号为DRKS00031220的随机对照试验（randomized controlled trial），针对因特定恐惧症（Specific Phobia）或广场恐惧症（Agoraphobia）导致临床显著飞行恐惧的个体（N=519），探究了四种心理策略对提升暴露疗法效果的作用。所有参与者均接受了标准化大型团体单次治疗（large-group one-session treatment，LG-OST），内容涵盖心理教育、治疗复盘及真实飞行暴露环节。参与者被随机分配至四种针对不同机制的试验组：同伴支持（SUPPORT）组、自我效能感（SELF-EFFIC）组、预期违背（EXPECT）组，以及躯体恐惧症状应对（COPE）组。这些目标机制会在平行开展的暴露飞行前及飞行过程中予以强化，每个试验组均使用独立航空器进行暴露飞行。所有试验组中，LG-OST均实现了短期与长期的症状显著缓解：恐惧评分减半，超过50%的参与者在6个月随访期内恢复飞行，约70%的参与者不再符合诊断标准。但未发现任一试验组的治疗效果优于其他组。尽管操控检验证实目标机制得到了部分激活（例如，同伴支持组的感知同伴支持程度更高，躯体症状应对组的呼吸技巧使用频率更高），但这些机制激活并未转化为具有差异的临床获益。本研究结果证实了LG-OST的有效性与可推广性，同时表明针对特定机制定制准备策略的附加价值可能有限。研究同时凸显了推进机制研究的必要性，以便更好地理解支撑暴露疗法成功的复杂交互过程。未来研究应聚焦于提升治疗可及性，并维持长期的治疗获益。