Background: With widespread smartphone ownership, mobile health apps (mHealth) can expand access to evidence-based interventions for mental health conditions, including posttraumatic stress disorder (PTSD). Research to evaluate new features and capabilities in these apps is critical but lags behind app development. The initial release of PTSD Coach, a free self-management app developed by the US Departments of Veterans Affairs and Defense, was found to have a positive public health impact. However, major stakeholder-driven updates to the app have yet to be evaluated. Objective: We aimed to characterize the reach, use, and potential impact of PTSD Coach Version 3.1 in the general public. As part of characterizing use, we investigated the use of specific app features, which extended previous work on PTSD Coach. Methods: We examined the naturalistic use of PTSD Coach during a 1-year observation period between April 20, 2020, and April 19, 2021, using anonymous in-app event data to generate summary metrics for users. Results: During the observation period, PTSD Coach was broadly disseminated to the public, reaching approximately 150,000 total users and 20,000 users per month. On average, users used the app 3 times across 3 separate days for 18 minutes in total, with steep drop-offs in use over time; a subset of users, however, demonstrated high or sustained engagement. More than half of users (79,099/128,691, 61.46%) accessed one or more main content areas of the app (ie, Manage Symptoms, Track Progress, Learn, or Get Support). Among content areas, features under Manage Symptoms (including coping tools) were accessed most frequently, by over 40% of users (53,314/128,691, 41.43% to 56,971/128,691, 44.27%, depending on the feature). Users who provided initial distress ratings (56,971/128,691, 44.27%) reported relatively high momentary distress (mean 6.03, SD 2.52, on a scale of 0-10), and the use of a coping tool modestly improved momentary distress (mean −1.38, SD 1.70). Among users who completed at least one PTSD Checklist for DSM-5 (PCL-5) assessment (17,589/128,691, 13.67%), PTSD symptoms were largely above the clinical threshold (mean 49.80, SD 16.36). Among users who completed at least two PCL-5 assessments (4989/128,691, 3.88%), PTSD symptoms decreased from the first to last assessment (mean −4.35, SD 15.29), with approximately one-third (1585/4989, 31.77%) of these users experiencing clinically significant improvements. Conclusions: PTSD Coach continues to fulfill its mission as a public health resource. Version 3.1 compares favorably with version 1 on most metrics related to reach, use, and potential impact. Although benefits appear modest on an individual basis, the app provides these benefits to a large population. For mHealth apps to reach their full potential in supporting trauma recovery, future research should aim to understand the utility of individual app features and identify strategies to maximize overall effectiveness and engagement. Trial Registration:

中文翻译：

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PTSD Coach 3.1 版：仔细研究这个更新的移动健康应用程序在公众中的覆盖面、使用和潜在影响

背景：随着智能手机的普及，移动健康应用程序 (mHealth) 可以扩大对心理健康状况的循证干预，包括创伤后应激障碍 (PTSD)。评估这些应用程序的新特性和功能的研究至关重要，但滞后于应用程序开发。由美国退伍军人事务部和国防部开发的免费自我管理应用程序 PTSD Coach 的初始版本被发现具有积极的公共卫生影响。但是，该应用程序的主要利益相关者驱动的更新尚未评估。客观的：我们旨在描述 PTSD Coach 3.1 版在公众中的覆盖面、使用和潜在影响。作为表征使用的一部分，我们调查了特定应用程序功能的使用，这扩展了之前在 PTSD Coach 上的工作。方法：我们在 2020 年 4 月 20 日至 2021 年 4 月 19 日的 1 年观察期内检查了 PTSD Coach 的自然使用情况，使用匿名应用内事件数据为用户生成摘要指标。结果：在观察期间，PTSD Coach 向公众广泛传播，达到约 150,000 总用户和每月 20,000 用户。平均而言，用户在 3 天内使用该应用程序 3 次，总共 18 分钟，随着时间的推移使用率急剧下降；然而，一部分用户表现出高度或持续的参与度。超过一半的用户 (79,099/128,691, 61.46%) 访问了应用程序的一个或多个主要内容区域（即管理症状、跟踪进度、学习或获得支持）。在内容区域中，管理症状（包括应对工具）下的功能访问频率最高，超过 40% 的用户（53,314/128,691，41.43% 至 56,971/128,691，44.27%，具体取决于功能）。提供初始痛苦评级的用户 (56,971/128,691, 44.27%) 报告了相对较高的瞬时痛苦（平均 6.03, SD 2.52, 在 0-10 的范围内），并且使用应对工具适度改善了短暂的痛苦（平均 -1.38，SD 1.70）。在完成至少一份 DSM-5 (PCL-5) 评估的 PTSD 检查表的用户中（17,589/128,691，13.67%），PTSD 症状大大高于临床阈值（平均 49.80，SD 16.36）。在完成至少两次 PCL-5 评估的用户中（4989/128,691, 3.88%），PTSD 症状从第一次评估到最后一次评估减少（平均值 -4.35, SD 15.29），约三分之一（1585/4989, 31.77%） ) 这些用户的临床显着改善。标准差 16.36)。在完成至少两次 PCL-5 评估的用户中（4989/128,691, 3.88%），PTSD 症状从第一次评估到最后一次评估减少（平均值 -4.35, SD 15.29），约三分之一（1585/4989, 31.77%） ) 这些用户的临床显着改善。标准差 16.36)。在完成至少两次 PCL-5 评估的用户中（4989/128,691, 3.88%），PTSD 症状从第一次评估到最后一次评估减少（平均值 -4.35, SD 15.29），约三分之一（1585/4989, 31.77%） ) 这些用户的临床显着改善。结论： PTSD Coach 继续履行其作为公共卫生资源的使命。在与覆盖面、使用和潜在影响相关的大多数指标上，3.1 版优于 1 版。尽管对个人的好处似乎不大，但该应用程序为大量人群提供了这些好处。为了让 mHealth 应用程序在支持创伤恢复方面发挥其全部潜力，未来的研究应该旨在了解各个应用程序功能的效用，并确定最大限度地提高整体有效性和参与度的策略。试用注册：