RESUMO
BACKGROUND: Tai chi has been commonly used as an allied health strategy that can support the improvement of mental health for individuals, yet the comparative effects of Tai chi versus non-mindful exercise on measures of anxiety, depression and general mental health are unknown. This study aims to quantitatively estimate the comparative effects between Tai chi and non-mindful exercise on measures of anxiety, depression, and general mental health and examine whether selected moderators of theoretical or practical importance moderate the effects. METHODS: Consistent with PRISMA guidelines for conduct and reporting, we located articles published before 31 Dec 2021 using Google Scholar, Pubmed, Web of Science, EBSCO (PsycArticles, PsycExtra, PsycInfo, Academic Search Premier, ERIC, MEDLINE). To be included in the analysis, studies were required to have (1) a design that randomly assigned participants to Tai chi and non-mindful exercise comparison condition or group. (2) anxiety, depression, or general mental health outcome measured at baseline and during or after Tai chi and exercise intervention. Study quality was judged using the tool for assessing study quality and reporting in exercise (TESTEX) for randomized controlled trials (RCTs). Three separate multilevel meta-analyses with random effects were performed to estimate the comparative effects of Tai chi versus non-mindful exercise on psychometric measures of anxiety, depression, and general mental health respectively. In addition, possible moderators were assessed accordingly for each meta-analysis. RESULTS: Twenty-three studies that included measures of anxiety (10), depression (14), and general mental health (11) involved 4370 participants (anxiety, 950; depression, 1959; general mental health,1461) and yielded 30 effects on anxiety, 48 on depression, and 27 on general mental health outcomes. Tai Chi training consisted of 1-5 sessions per week, 20-83 min per session, and 6-48 weeks. After adjusting for nesting effects, the results showed significant small-to-moderate effects of Tai chi versus non-mindful exercise on the measure of anxiety (d = 0.28, 95 % CI, 0.08 to 0.48), depression (d = 0.20, 95 % CI, 0.04 to 0.36), and general mental health (d = 0.40, 95 % CI, 0.08 to 0.73). Further moderator analyses showed that baseline general mental health T-score and study quality influenced the effects of Tai chi versus non-mindful exercise on measure of general mental health. CONCLUSION: Compared to non-mindful exercise, the small body of studies reviewed here tentatively supports that Tai chi is more effective in reducing anxiety and depression and improving general mental health than non-mindful exercise. Higher-quality trials are needed to standardize Tai chi and non-mindful exercise exposure, quantify mindfulness elements in Tai chi practice, and control expectations on conditions to better determine the psychological effects of both exercise properties.