Assessment schedule.

BackgroundEmergency service workers (ESWs) are routinely exposed to highly stressful and potentially traumatic events leading to high rates of psychological distress. Early intervention is vital to prevent chronic impairment and/or psychiatric disorders, with digital health innovations (e.g., smartphone apps) offering a potential means of scaling such intervention while overcoming barriers to help-seeking in this population. This study aims to evaluate the efficacy of an app designed to reduce psychological distress and related outcomes in ESWs.MethodsWe conducted a randomised controlled trial with ESWs experiencing psychological distress (Kessler Psychological Distress Scale; K10) score >15. Participants were assigned to the intervention group, a full version of the Build Back Better app (including mindfulness, behavioural activation, trauma-focused cognitive therapy skills, activity and mood monitoring, and healthy coping strategies) or a mood/activity tracking-only version of the same app. Assessment occurred via online self-report questionnaires at baseline (T0) and at 1- and 3-month post-baseline (T1, T2) timepoints. The primary outcome was the K10 score at T2. Linear mixed model analyses were conducted based on the intention-to-treat principle.ResultsN = 880 ESWs were randomized to the full (n = 440) or tracking-only (n = 440) condition. There was no Time x Condition effect for K10 scores, with both conditions showing similar improvements from baseline to 1-month (all ps ps p = .002, d = −1.43).ConclusionDespite consistent improvement across both app conditions, the minimal between group differences found here highlight the difficulties in developing effective, scalable resources for ESWs and the limitations of unguided digital programs more broadly.Trial registrationAustralian New Zealand Clinical Trials Registry ACTRN12622001324707背景 应急服务人员（Emergency Service Workers, ESWs）日常需暴露于高压力且潜在创伤性的事件中，由此引发了较高比例的心理困扰。早期干预对于预防慢性功能损害及/或精神障碍至关重要，而数字健康创新技术（如智能手机应用程序）为扩大此类干预的覆盖范围、同时克服该群体寻求帮助的障碍提供了可行途径。本研究旨在评估一款专为降低应急服务人员心理困扰及相关症状而设计的应用程序的有效性。 方法 本研究针对心理困扰评分（克塞勒心理困扰量表（Kessler Psychological Distress Scale, K10））>15分的应急服务人员开展了一项随机对照试验。受试者被随机分配至两个干预组：一组使用完整版本的Build Back Better应用程序（包含正念、行为激活、创伤聚焦认知治疗技巧、活动与情绪监测以及健康应对策略），另一组仅使用该应用程序的情绪/活动追踪版本。评估采用线上自报告问卷形式，分别在基线（T0）、基线后1个月（T1）及3个月（T2）三个时间点进行。主要结局指标为T2时点的K10评分。本研究基于意向治疗（intention-to-treat）原则开展线性混合模型分析。 结果 共880名应急服务人员被随机分配至完整程序组（n=440）与仅追踪组（n=440）。两组的K10评分未呈现时间×干预组交互效应，且在基线至1个月时点均展现出相似的改善（所有p值均>0.05），在基线至3个月时点则均出现显著改善（p = 0.002，d = −1.43）。 结论 尽管两类应用程序干预组均取得了一致的症状改善，但本研究中两组间极小的组间差异凸显了为应急服务人员开发有效且可规模化的心理资源所面临的挑战，同时也反映了非指导性数字项目的普遍局限性。 试验注册 澳大利亚新西兰临床试验注册中心（Australian New Zealand Clinical Trials Registry）ACTRN12622001324707