@文章{信息:doi/10.2196/26397，作者=“Keller, Jan和Roitzheim, Christina和Radtke, Theda和Schenkel, Konstantin和Schwarzer, Ralf”，标题=“普通人群中自我有效和目标导向的智能手机使用的移动干预:随机对照试验”，期刊=“JMIR移动健康Uhealth”，年=“2021”，月=“11”，日=“23”，卷=“9”，数=“11”，页=“e26397”，关键词=“问题智能手机使用;智能手机解锁;智能手机;行为改变;自我效能感;行动计划;数字排毒;超时;背景:人们在日常生活中大部分时间都在使用智能手机。尽管智能手机在日常生活中有各种好处，但智能手机使用的问题形式存在，这些形式与负面的心理和生理后果有关。 To reduce problematic smartphone use, existing interventions are oftentimes app-based and include components that help users to monitor and restrict their smartphone use by setting timers and blockers. These kinds of digital detox interventions, however, fail to exploit psychological resources, such as through promoting self-efficacious and goal-directed smartphone use. Objective: The aim of this study is to evaluate the theory-based smartphone app ``Not Less But Better'' that was developed to make people aware of psychological processes while using the smartphone and to support them in using their smartphone in accordance with their goals and values. Methods: In a randomized controlled trial, effects of a 20-day intervention app consisting of five 4-day training modules to foster a goal-directed smartphone use were evaluated. In the active control condition (treatment as usual), participants received a digital detox treatment and planned daily time-outs of at least 1 hour per day. Up to a 3-week follow-up, self-reported problematic smartphone use, objectively measured daily smartphone unlocks, time of smartphone use, self-efficacy, and planning towards goal-directed smartphone use were assessed repeatedly. Linear 2-level models tested intervention effects. Mediation models served to analyze self-efficacy and planning as potential mechanisms of the intervention. Results: Out of 232 enrolled participants, 110 (47.4{\%}; 55 participants in each condition) provided data at postintervention and 88 (37.9{\%}; 44 participants in each condition) at 3-week follow-up. Both conditions manifested substantial reductions in problematic smartphone use and in the amount of time spent with the smartphone. The number of daily unlocks did not change over time. Further, modelling changes in self-efficacy as a mediator between the intervention and problematic smartphone use at follow-up fit well to the data and showed an indirect effect (b=--0.09; 95{\%} bias-corrected bootstrap CI --0.26 to --0.01), indicating that self-efficacy was an important intervention mechanism. Another mediation model revealed an indirect effect from changes in planning via smartphone unlocks at postintervention on problematic smartphone use at follow-up (b=--0.029, 95{\%} bias-corrected bootstrap CI --0.078 to --0.003). Conclusions: An innovative, theory-based intervention app on goal-directed smartphone use has been found useful in lowering problematic smartphone use and time spent with the smartphone. However, observed reductions in both outcomes were not superior to the active control condition (ie, digital detox treatment). Nonetheless, the present findings highlight the importance in promoting self-efficacy and planning goal-directed smartphone use to achieve improvements in problematic smartphone use. This scalable intervention app appears suitable for practical use and as an alternative to common digital detox apps. Future studies should address issues of high attrition by adding just-in-time procedures matched to smartphone users' needs. Trial Registration: German Clinical Trials Register DRKS00017606; https://tinyurl.com/27c9kmwy ", issn="2291-5222", doi="10.2196/26397", url="https://mhealth.www.mybigtv.com/2021/11/e26397", url="https://doi.org/10.2196/26397", url="http://www.ncbi.nlm.nih.gov/pubmed/34817388" }