Effectiveness and mechanism of a 4-week online self-help mindfulness intervention among individuals with emotional distress during COVID-19 in China Author: Ruilin Ju#1, Wingsze Chiu#1, Yinyin Zang1, Stefan G Hofmann2,3, Xinghua Liu4 Affiliation: <sup>1</sup> Beijing Key Laboratory of Behavior and Mental Health, School of Psychological and Cognitive Sciences, Peking University, No. 5 Yiheyuan Road Haidian District, Beijing, People&#x27;s Republic of China. <sup>2</sup> Department of Clinical Psychology, Philipps-University Marburg, Marburg, Germany. <sup>3</sup> Department of Psychological and Brain Sciences, Boston University, 900 Commonwealth Avenue, 2nd Floor, Boston, MA, 02215, USA. <sup>4</sup> Beijing Key Laboratory of Behavior and Mental Health, School of Psychological and Cognitive Sciences, Peking University, No. 5 Yiheyuan Road Haidian District, Beijing, People&#x27;s Republic of China. xinghua_liu@pku.edu.cn. Conference/Journal: BMC Psychol Date published: 2022 Jun 13 Other: Volume ID: 10 , Issue ID: 1 , Pages: 149 , Special Notes: doi: 10.1186/s40359-022-00831-7. , Word Count: 292 Background: Many people suffered from emotional distress especially during the COVID-19 pandemic. In order to alleviate emotional distress, more accessible psychological intervention programs, such as online intervention programs, are needed. The study aimed to investigate the efficacy and the potential mechanism of a 4-week, online, self-help mindfulness-based intervention to manage emotional distress during the COVID-19 pandemic between February 3 and May 20, 2020. Methods: A total of 302 individuals with high emotional distress completed a self-help mindfulness course, which lasted 30-60 min per day for 28 consecutive days. Participants who registered in the program later were included in the analyses as the control group (n = 315). Levels of mindfulness, perceived stress, emotional distress, anxiety and depression were assessed at baseline(T1), week 1(T2), week 2(T3), week 3(T4) and week 4(T5). Results: Significant Group by Time interaction effects were found on mindfulness, perceived stress, emotional distress, anxiety and depression (p < 0.001). Compared to the control group, the intervention group had a greater increase in changes of all outcome variables (p < 0.001). Random intercept cross-lagged analyses showed that compared with control group, mindfulness at T2 and T4 negatively predicted stress at T3 and T5, and mindfulness at T2 and T4 negatively predicted depression at T3 and T5 while depression at T3 predicted mindfulness at T4 in the mindfulness group. Conclusions: The results suggest that a 4-week self-help online mindfulness intervention improved mindfulness and reduced stress, emotional distress, anxiety and depression symptoms. Compared to the control group, changes in mindfulness preceded changes in stress, and mindfulness and depression reciprocally influenced each other during the intervention. Trial registration Chinese Clinical Trial Registry: ChiCTR2000034539. Registered 9 July 2020-Retrospectively registered, http://www.chictr.org.cn/edit.aspx?pid=55721&htm=4 . Keywords: COVID-19; Emotional distress; Mindfulness; Online intervention; Self-help intervention. PMID: 35698165 DOI: 10.1186/s40359-022-00831-7