Abstract
Anxiety has become a global public health problem. Tai chi offers one possible way of reducing anxiety. The purpose of this study was to examine studies from 1989 to March 2014 to assess whether tai chi can be an efficacious approach for managing anxiety. A systematic search of Medline, CINAHL, and Alt HealthWatch databases was conducted for quantitative articles involving applications of tai chi for anxiety. A total of 17 articles met the inclusion criteria. Of these, 8 were from the United States, 2 from Australia, 2 from Japan, 2 from Taiwan, and 1 each from Canada, Spain, and China. Statistically significant results of anxiety reduction were reported in 12 of the studies reviewed. Despite the limitations of not all studies using randomized controlled designs, having smaller sample sizes, having different outcomes, having nonstandardized tai chi interventions, and having varying lengths, tai chi appears to be a promising modality for anxiety management.
Introduction
In China, tai chi, a type of mindfulness-based exercise, 1 has been used as a form of therapy for multiple ailments since the 12th century. 2 The therapeutic benefits of tai chi reported in the literature are related to improvement in memory, concentration, depression, anxiety, cancer, arthritis, and blood pressure.3,4 Practicing tai chi regularly has also been known to alleviate health problems associated with aging and inactivity—improving the balance of elderly for fall prevention. Although benefits have widely been reported in the literature, the physiological mechanism by which tai chi improves health is not fully understood. 5
Tai chi utilizes slow, gentle movements where practitioners shift their weight between feet while moving their arms. 6 The exercise consists of elements that combine martial arts, meditation, imagery, and deep breathing. 6 Practitioners of almost any age can perform tai chi, including the elderly and those with physical limitations or disabilities. 4 Due to the relatively simple nature of learning and practicing tai chi, and not needing expensive equipment or medicine, many Westerners are turning to it as an alternative and/or complementary treatment for their illnesses. 6 The increase in popularity and prevalence of tai chi, along with other forms of complementary and alternative medicine, may be due to the focus on one’s health as opposed to the disease they are attempting to treat. 4 Studies also suggest that the social stigma related to conventional therapies to treat anxiety and stress disorders, such as medications and behavioral therapy, has led some sufferers to look for alternative forms of treatment. 7
The World Health Organization surmises that mental illness, including anxiety, will become the second most common disability by 2020. 7 In the United States, there are an estimated 40 million adults suffering from anxiety, annually. 2 Anxiety is a complex disease, closely related to the physical and mental state of the sufferer, as well as their ability to interact with their environment and society. 7 Anxiety disorders include general anxiety disorder, social phobia, obsessive compulsive disorder, panic disorder, and posttraumatic stress disorder. Distinct symptoms are displayed for those suffering from anxiety, including shortness of breath, dizziness, heart palpitations, gastrointestinal issues, and an abnormally high body temperature. 8 Anxiety sufferer may experience life dissatisfaction, 4 and the disorder can be detrimental to their social and emotional well-being. 2
Reducing a person’s anxiety can improve their energy, quality of life, memory, and cognitive functioning. 9 The current therapies used to treat anxiety include antidepressants, cognitive behavioral therapy, benzodiazepines such as Xanax, self-help techniques, and life style modifications to remove the triggers of anxiety from one’s life. Cognitive behavioral therapy includes components such as psychoeducation, relaxation training, and behavioral reconstruction. Unfortunately, the use of cognitive behavioral therapy and/or antidepressants is estimated to alleviate symptoms of anxiety in only 50% to 65% of patients. Many patients are left with symptoms of their anxiety and are in need of alternative therapies. One such option for patients has been benzodiazepines. These drugs are often prescribed to patients with panic disorders or episodes of mania related to their anxiety. Although efficacious, benzodiazepines are usually described for short-term use as they are highly addictive and patients have been known to abuse such drugs. 8 Due to the lack of safe and effective options for anxiety sufferers, it is imperative that additional avenues of therapy, including nonchemical treatments, be explored. 6
Alternative and complementary forms of medicine to treat anxiety include acupuncture, meditation, herbal supplements, homeopathic techniques, and mind–body practices such as tai chi. 8 Tai chi offers benefits to anxiety sufferers without the side effects and risks associated with prescription drugs.8,9 Because tai chi integrates low physical impact body movements with deep breathing and mental concentration, relaxation is possible, thus making it an alternative option to conventional anxiety treatments. 10 Additionally, anxiety disorders are often comorbid with other physical and psychological problems. Because tai chi is a form of exercise, it can act as a tool for health promotion—mitigating the ancillary health problems of anxiety sufferers. 2
The research question being addressed in this study include the following: Is tai chi efficacious alone, or in tangent with medication or other conventional therapies, to significantly reduce anxiety levels of health and anxiety-stricken subjects and is there sufficient data available to draw conclusions regarding the efficacy of tai chi in treating anxiety? What are the methodological limitations of present research studies and how can these be addressed in future research? The purpose of this review is to provide evidence that can facilitate the improvement of clinical guidelines for the treatment of anxiety.
Methods
The inclusion criteria for this review include studies that (a) were published in the English language; (b) were published between January 1, 1989, and March 31, 2014; (c) were peer-reviewed; (d) enlisted some form of tai chi as part of an intervention; (e) used a quantitative study design; (f) measured anxiety as an outcome (State–Trait Anxiety Inventory, Beck’s Anxiety Inventory, Visual Analog Scale, and so on); and (g) were indexed in Medline, CINAHL (Cumulative Index to Nursing and Allied Health), or Alt HealthWatch. Studies that were excluded include those that (a) did not use tai chi as a treatment option; (b) did not measure anxiety as an outcome and; (c) did not index in any of the following databases: CINAHL (Cumulative Index to Nursing and Allied Health), Medline, or Alt HealthWatch. The logic to including studies over a long time period is to increase the sample of studies reviewed as the literature related to tai chi and anxiety is not vast. In addition, studies that measured anxiety as a comorbidity to other ailments were not excluded as they met the eligibility criteria.
The 3 phases utilized to return studies to meet the aforementioned criteria include a Boolean search, distillation, and reference review (Figure 1). CINAHL, Medline, and Alt HealthWatch databases were indexed to find studies meeting the criteria for this review as part of Phase 1. The Boolean search term used was “Tai Chi AND Anxiety.”
Three-phase data extraction process.
Using the above-mentioned search terms, 115 articles were returned from CINAHL (n = 48), Medline (n = 46), and Alt HealthWatch (n = 21). Phase II, distillation, was composed of eliminating: duplicates (n = 21), review/discussion/secondary data articles (n = 52), studies not incorporating tai chi as an intervention (n = 14), and those not using a quantitative design (n = 1). Of the remaining articles (n = 27), 10 were excluded, including one that included only the intervention protocol. The remaining (n = 17) articles satisfied the eligibility criteria (Figure 1).
Results
The results of the data extraction process included 16 articles meeting the eligibility criteria set forth in this review. The year of publication, authors, country of origin, study design, sample, and setting, age of participants, intervention modality and dosage, outcome measures, and salient finding are listed in Table 1. The studies are listed in ascending order by year of publication.
Summary of Tai Chi Interventions for Anxiety Done Between 1989 and March 2014 (n = 17).
Abbreviations: EKG, electrocardiogram; EEG, electroencephalogram; BMI, body mass index.
Discussion
The purpose of this review was to analyze the efficacy of tai chi as an alternative and/or complementary treatment for anxiety by reviewing articles published from January 1, 1989, to March 31, 2014. A total of 17 articles met the inclusion criteria. Below, the studies are analyzed specifying the reductions in anxiety, sample size, bias, dosage and duration of interventions, study design, and the reliability and validity of the scales used.
Of the 17 studies, 8 were performed in the United States,2,9,13,16,18,19,20,22 2 were performed in Australia,11,12 2 in Japan,5,14 2 in Taiwan,15,21 and 1 each in Canada, 17 Spain, 10 and China. 23 Statistically significant results were reported in 12 of the studies reviewed.2,10 –13,15,16,18,19,21 –23 It is important to note that in some of these studies the changes were significant when comparing intragroup changes (baseline vs study end),2,10,13,19 whereas others compared intergroup changes (tai chi intervention vs control group).11,12,15,16,18,21 –23 In some cases, statistically significant reductions were noted for both tai chi and exercise intervention groups16,18 as compared with baseline and/or the control group.
Considering a little more than half of the studies (n = 10) enlisted an intervention targeting anxiety and ancillary ailments (severe learning disabilities [attention deficient and/or hyperactivity], 17 degenerative diseases related to aging,5,9,18,23 prenatal depression, 22 HIV/AIDS, 16 geriatric depression, 20 and fibromyalgia 10 ), it can be difficult to determine if anxiety reductions were secondary to reductions in comorbidities of anxiety. This means that some subjects suffered anxiety as a secondary condition, while others were healthy, and still other subjects were diagnosed with generalized anxiety disorder as their primary ailment. Due to these variations in anxiety, results may not be comparable among studies. Additionally, some studies utilized tai chi as a complementary treatment. Since tai chi was an addition, after medication and other therapies had already been prescribed to these subjects, it was not deemed a confounding factor related to the improvement in anxiety reported. Some examples of such studies were by Lavretsky and colleagues, 20 who gave Escitalopram, and Song and colleagues, 23 who gave antianxiety medication along with tai chi.
The articles reviewed used a diversity of scales to measure anxiety outcomes, including State–Trait Anxiety Inventory—including those for children (State–Trait Anxiety Inventory for Children) and youth (State–Trait Anxiety Inventory Form Y1/State–Trait Anxiety Inventory Form Y2); Hamilton Anxiety Scale; Generic Quality of Life Inventory-74; Taylor Manifest Anxiety Scale; Hamilton Disease Rating Scale; Fibromyalgia Impact Questionnaire; Multiple Affect Adjective Check List; the Multiple Affect Adjective Check List–Revised; Hospital Anxiety and Depression Scale; and the General Health Questionnaire. To evaluate the efficacy of an intervention, it is important that researchers report the psychometric properties of the scales they use, as these determine change in anxiety. Specifically, the State-Trait Anxiety Inventory for Children scale was reported to have an α reliability of .82 for males and .87 for females, 17 which is acceptable psychometrically. For another study utilizing a quasi-experimental design measuring tai chi among a large group of participants, Cronbach’s α for their Beck Anxiety Inventory scale was .91, 21 which is again indicative of acceptable internal consistency. It is important to note that the State–Trait Anxiety Inventory scale has been in several studies all reporting the high validity and internal consistency of the scale. 22 Additionally, another study reported State–Trait Anxiety Inventory scale with test–retest reliabilities ranging from .62 to .85 and a Cronbach’s α of .93. 18 In a randomized control trial of 37 participants using the State–Trait Anxiety Inventory scale, researchers reported the Cronbach α values of .84 for trait anxiety and .89 for state anxiety, respectively. 15 It is also important to note that each of these scales is subjective and based on the self-reported feelings of the subject. However, with the use of pre- and posttests, along with comparison groups, these inherent biases are minimized. The studies that did report the psychometric properties of the scales used were high, but only few reported those properties.
For this review, it is important to differentiate between studies that utilized the randomized control trial design5,12,15,16,18,20,22,23 as opposed to quasi-experimental,9,21 pretest/posttest design,2,10,13,19 or any variation11,14,17 that does not include randomly assigning subjects to a control or intervention group. Randomized control designs are characterized by their use of randomly assigning subjects to control and intervention groups—making them the most robust type of study design. Eight of the studies utilized the randomized control trial design. Quasi-experimental designs, although they assign subjects to a control or intervention group, do not randomize the sample—sometimes matching subjects between groups. Two of the studies utilized quasi-experimental design. Pretest/posttest design does not utilize a comparison group—only comparing baseline measures with those reported at the end of the intervention. Four of the studies use this type of design. Additionally, 3 studies utilized some other type of design, including a 3-factorial design with variations in phase of tai chi (before/after), experience, and time of practice for 2 groups. 11 Another study that did not utilize the 3 common designs indicated above involved 2 interventions for 2 different samples. 14 Last, one study applied a single case research design—focusing on a small sample size of children suffering from attention deficient hyperactivity disorder. 17
Sample size is also an important factor in determining the robustness and rigor of a study. The sample size ranged from 3 to 133, with a mean sample size of 53 (standard deviation = 38). A large number of studies have used sample size less than 30 participants. For such studies not much confidence can be asserted in the results. It is very important for future studies to conduct power analysis, and a software G*Power can do that analysis very easily.
Past reviews have indicated that duration and dosage of intervention can have an effect on the efficacy of tai chi to treat anxiety. 4 Intervention duration varied in the 17 studies reviewed from 1 day12,19 to 1 year. 11 Specifically, the majority of the studies lasted between 8 and 12 weeks.2,5,13,15 –18,20 –23 Likewise, the dosage of intervention also varied from one 1-minute session 14 to 60-minute classes 3 times a week for up to 28 weeks.10,13,18 The mean total instruction time for tai chi was 30 hours (standard deviation = 34 hours). In terms of duration of each session, the majority of the studies utilized hour-long sessions of tai chi practice,2,9,10,12,13,16 –18,20,21 which seems to be practically feasible.
All of the studies provided regular tai chi practice in a group setting, allowing practice teachers to ensure students are practicing tai chi correctly. Additionally, several studies used a sign-in sheet to monitor the dosage of tai chi subjects received. This also allowed for the monitoring of attrition rates. Some studies reported attrition rates due to participants dropping out of the study but not all studies reported these rates. High attrition rates for any form of practice can alter the applicability of the treatment option. Incentives to ensure subjects remained in the intervention were used by some studies.
In addition, no study incorporated the use of a behavioral theory to help participants adopt and use the behavior of tai chi. Use of behavioral theory can make the interventions more efficient and also gauging changes in the constructs of a behavioral theory can provide insights into the efficacy of these interventions. 24 More specifically, theory can provide guidance into which components work for effecting behavior change and which components do not.
There are some limitations of the present review. First this is a qualitative review and not a meta-analysis, which is quantitative and gives an indication of the effect size of the intervention. Second, this study only tapped 3 databases in English language. It is likely that there may be some tai chi interventions and their evaluations published in Chinese or other languages that were missed in this review. However, the 3 databases chosen for this study carry a large majority of publications in the area of complementary and alternative systems of medicine. Finally, there could have been publication bias as only interventions with successful results are generally accepted for publication and the ones that are not successful get rejected. However, in the present review we did find several studies that did not show changes in anxiety related outcomes but had still been published.
Conclusions
Anxiety is a major public health problem and there is need to explore alternative and complimentary approaches for preventing, treating, and managing anxiety. Tai chi seems to offer such an approach. A total of 17 interventions from 1989 to March 2014 looked at tai chi and its efficacy in alleviating anxiety. Of these 12 interventions were able to find positive effects in outcome measures related to anxiety. Despite the limitations of not all studies using randomized controlled design, having smaller sample sizes, having different outcome measures, having nonstandardized tai chi intervention, and having varying lengths of intervention, tai chi is a promising modality for anxiety management. All practitioners working with preventing or managing anxiety must teach tai chi as one of the approaches for anxiety reduction.
Footnotes
Author Contributions
MS conceptualized the study, developed the inclusion criteria, collected the data, developed the table, analyzed the data, and reviewed the article. TH collected the data, analyzed the data, and wrote the first draft of the article.
Declaration of Conflicting Interests
The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethical Approval
This study did not warrant institutional review board review as no human subjects were involved.