Complementary Therapies in Medicine (2015) 23, 516—534

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REVIEW

A systematic review and meta-analysis ofthe effects of Qigong and Tai Chi fordepressive symptoms

Xin Liua,b,c,∗, Justin Clarkd, Dan Siskindc,e,f, Gail M. Williamse,Gerard Byrnec,g, Jiao L. Yangh, Suhail A. Doi i

a The Third Clinical School, Zhejiang Chinese Medical University, Hangzhou, Chinab Wuhan Sport University, Wuhan, Chinac School of Medicine, The University of Queensland, Brisbane, Australiad Drug Arm Australia Library, Brisbane, Australiae School of Population Health, The University of Queensland, Brisbane, Australiaf Metro South Addiction and Mental Health Service, Brisbane, Australiag Mental Health Service, Royal Brisbane & Women’s Hospital, Brisbane, Australiah Department of Culture and Art Teaching, University of International Business and Economics, Beijing,Chinai Research School of Population Health, The Australian National University, Canberra, Australia

Received 30 September 2014; received in revised form 11 May 2015; accepted 24 May 2015Available online 27 May 2015

KEYWORDSQigong;Tai Chi;Depressivesymptoms;Meta-analysis

AbstractBackground: Qigong and Tai Chi are the two most popular traditional Chinese exercises, knownas mind-body movement therapies. Previous studies suggest that Qigong and Tai Chi may bebeneficial in reducing depressive symptoms. This was the first study to systematically reviewand compare the effects of Qigong and Tai Chi on depressive symptoms.Methods: A systematic search of six electronic databases was undertaken through to February2014, for randomized controlled trials (RCTs) which reported depressive symptoms measured bya depressive symptom rating scale. The standardized mean difference in depressive symptomsscore between Qigong or Tai Chi and a control group (at the end of follow-up) was extracted asa primary outcome. The secondary outcome was the standardized mean gain in symptom score(SMG) relative to the baseline from individual arms of the RCTs for various forms of care includingQigong, Tai Chi, usual care, other exercise, education and miscellaneous interventions.Results: Thirty studies with a total of 2328 participants (823 males and 1505 females) wereincluded. A significant effect was found for the Qigong interventions (Cohen’s d −0.48 95% CI−0.48 to −0.12; SMG −0.52, 95% CI −0.79 to −0.26). There was no significant effect seen for

∗ Corresponding author at: Translational Research Institute, School of Medicine, The University of Queensland, 199 Ipswich Road, Wool-loongabba, Brisbane, QLD 4012, Australia. Tel.: +61 7 3443 7483; fax: +61 7 3176 5663.

E-mail address: xin.liu@uqconnect.edu.au (X. Liu).

http://dx.doi.org/10.1016/j.ctim.2015.05.0010965-2299/© 2015 Elsevier Ltd. All rights reserved.

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A systematic review and meta-analysis of the effects of Qigong and Tai Chi for depressive symptoms 517

Tai Chi for the primary endpoint. No mean change in symptom scores were seen for Tai Chi, usualcare, other exercises, education and the ‘miscellaneous’ group in pre-post assessment in singlearms. The Qigong results were found to be robust in sensitivity analyses.Conclusions: Qigong appears to be beneficial for reducing depressive symptom severity. However,given the low quality of the included studies and the documented evidence of publication bias,these results should be viewed cautiously.© 2015 Elsevier Ltd. All rights reserved.

Contents

1. Introduction..............................................................................................................5172. Methods .................................................................................................................. 518

2.1. Data sources and eligibility criteria................................................................................5182.2. Data extraction and quality assessment ........................................................................... 5182.3. Outcome measure and statistical analyses.........................................................................518

3. Results ................................................................................................................... 5293.1. Search results ..................................................................................................... 5293.2. Characteristics of included studies ................................................................................ 5293.3. Participants ....................................................................................................... 5293.4. Quality of the studies..............................................................................................5293.5. Quantitative synthesis .............................................................................................529

3.5.1. Primary outcome..........................................................................................5293.5.2. Secondary outcome.......................................................................................529

3.6. Sensitivity analyses................................................................................................5294. Discussion ................................................................................................................ 529

Conflict of interest statement ............................................................................................ 532Acknowledgements ....................................................................................................... 532Appendix A. Supplementary data.......................................................................................532References ............................................................................................................... 533

1. Introduction

Depression is a serious medical condition, with an esti-mated 350 million people of all ages affected worldwide.1

Depression is associated with a range of physical illnesses,including stroke, diabetes, cancer, arthritis, osteoporosis,and obesity,2—4 and the onset of depression incrementallyworsens the latter health problems.5—7 Interventions totackle this problem are therefore important and previousstudies have indicated an important role for physical activityin the management of depression.8

Specialized physical activity interventions such as Qigongand Tai Chi have been shown to be effective in reducingdepressive symptoms in previous studies.9—13 Qigong and TaiChi are the two most popular traditional Chinese exercises,known as mind and body movement therapies. Qigong is atraditional Chinese medical exercise and Tai Chi is a type ofChinese martial art. Qigong came into being earlier than TaiChi, and has been recognized as a ‘medical’ exercise in theTraditional Chinese Medicine field for thousands of years.14

There are many styles of Qigong, such as Daoyin Qigong,WuQinXi (Five Animals Qigong) and BaDuanJin (Eight-sectionBrocades Qigong). In contrast, Tai Chi was created by Mr.Chen Wang Ting (a retired General from army) as martialarts more than 300 years ago (in 1600s), named Chen styleTaijiquan.15 Apparently, Qigong is a health/medial exer-cise, consisting of movements with health functions andwith mind activity playing a predominant role in training.

Therefore, Qigong focuses more on ‘inside’ energy flow thanTai Chi. Qigong can be practiced as a ‘static’ (sitting, lying orstanding) or ‘dynamic’ (moving) style, and is generally easierto master than Tai Chi. Tai Chi can be practiced as standingand mainly moving style (not sitting or lying) and was ini-tially a martial art, consisting of movements with fightingfunctions and therefore it focuses on ‘outside’ defendingand attacking intention while practicing. However, in linewith cultural development, it has now evolved into manydifferent gentle styles, such as ‘Yang style’, ‘Sun style’,‘Wu style’, ‘24 forms’, ‘48 forms’ and ‘42 forms’, and itsfunction/intention has also changed accordingly. Therefore,people, especially the aging group, nowadays practice it forhealth at a slow pace.

Although some reviews on the effects of Qigong and TaiChi have also been conducted,9—13 they were not conclusivebecause they were either not quantitative reviews or hadseveral limitations. For example, there has just been onlyone previous meta-analysis on Qigong in relation to depres-sive symptoms that examined 10 randomized controlledtrials (RCTs) with quantitative data but pooled only subsetsof 2, 3 or 4 RCTs (by type of control group)9 and the resultswere only suggestive of a beneficial effect. When it comes toTai Chi, one meta-analysis12 combined both RCTs and obser-vational studies while another meta-analysis combined justfour RCTs and 253 participants13 with both suggesting a sig-nificant effect of Tai Chi on depression scores. However,this was inconclusive given the small numbers. A subsequent

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518 X. Liu et al.

meta-analysis that combined Tai Chi and Qigong RCTs foundno effect on depression scores, though this was primarily astudy in cancer patients.10 The latter body of evidence hasalso been backed up by a comprehensive review on the topicof meditative movements which suggests that the currentdata is inconclusive with regard to depressive symptoms.11

Finally, none of the reviews assessed and compared the dif-ference between Qigong and Tai Chi in terms of the effecton depressive symptoms.

This study was therefore undertaken to (1) perform amore rigorous review and analysis of the effect of Qigongand Tai Chi on depressive symptoms based only on RCT dataand (2) to compare the effect of Qigong and Tai Chi withthe changes seen in control groups that include usual care,other exercises and education.

2. Methods

2.1. Data sources and eligibility criteria

A systematic search of the literature was conducted inPubMed, Cochrane (CENTRAL), Embase, CINAHL, AMED,and PsycINFO for all citations that referred to eitherQigong or Tai Chi and depressive symptoms until February,2014. The specific keywords included were depression,depressions, depressive symptoms, depressive symptom,emotional depression, Qigong, Qi Gong, Ch’i Kung, breathingexercises, respiratory muscle training, Tai Chi, Tai Ji, Tai-ji,Tai Ji Quan, Taiji, Taijiquan, or Tai Chi Chuan. Controlledvocabulary terms (e.g. MeSH terms) were also used for eachof databases.

The inclusion of studies was restricted to random-ized controlled trials reporting prospective use of Qigong(defined as any exercise method that included Qigong train-ing, external Qigong therapy and breathing training) or TaiChi (defined as any exercise method that included Tai Chitraining) interventions. Additionally, there were no restric-tions on mean age (mean age greater than or equal to 60years) or co-morbidities (defined as any additional medicalcondition other than depression). Finally, all studies wererestricted to those that (a) had baseline assessment on adepression symptom scale (irrespective of whether they hadbeen diagnosed with depression or not); (b) had clearlyreported pre-intervention and post-intervention results inan extractable format; and (c) were written in English lan-guage.

2.2. Data extraction and quality assessment

Data was extracted for each study and is summarizedin the data extraction table (see Tables 1 and 2). Thedata abstracted included the characteristics of each study,including pre-intervention and post-intervention depressionsymptom scores allocated to Qigong, Tai Chi or any of thecontrol groups; associated conditions; intervention style,duration and frequency; and subject demographic data,including age range, gender, and sample size during thestudy. The control groups were categorized into usual care,other exercise, education, and a ‘miscellaneous’ group.The latter consisted of weekly telephone support, news-paper reading group, mahjong leisure activity, handicraft

leisure control activity, non-exercise control, attention con-trol intervention (including the wellness education andstretching program), basic rehabilitation activities (includ-ing self-care training, remedial activities, and educationalprograms), and control group without details.

Two outcomes were of interest: the standardized meandifference (d) in depression scores at the end of follow-upand the standardized mean gain (SMG) in depression scoresfrom baseline to end of follow-up. The latter was necessarygiven that all control groups are different across RCTs, andtherefore this secondary outcome (pre-post single arm anal-ysis) is required to demonstrate that all control arms havesimilar null effects. While d represents a two arm compari-son of scores at the end of follow-up, the SMG outcome waspooled across single arms of the RCT’s. The quality of eachstudy was assessed using a specifically created methodologi-cal quality checklist for each outcome (separate assessmentfor two group comparisons and pre-post comparisons assources of systematic error are different by outcome) modi-fied from several sources including the GRADE guidelines andCochrane Collaboration’s tool for assessing risk of bias.16,17

For each study, the questions assessed several domains suchas study design, selection, information, confounding, andanalytical biases (see Tables 3 and 4). The maximum scoreswere 19 for the standardized mean difference outcome and13 for the standardized mean gain outcome. It should beemphasized that these are not validated quality assess-ment instruments because these items are usually basedon the consensus among experts, implicitly based on bothempirical evidence and personal opinion,18 differ based onoutcomes and study topic and therefore will vary acrossindividual meta-analyses.19 Therefore, while items are wellrecognized, scales necessarily will vary and validation, whilepossible, is not as important as it would be for say scalesthat assess fixed constructs such as depression or qualityof life.19

Quality items were weighted equally given the paucity ofmeta-epidemiological studies informing us otherwise. Theonly exceptions were randomization and allocation con-cealment that were rated higher empirically. For all othersafe-guards one point was assigned if it was present andzero otherwise. The quality score (Qi) was then calculatedby summing the points awarded for each question and divid-ing this by the maximum within each meta-analysis, therebyrescaling between zero and one.

2.3. Outcome measure and statistical analyses

The primary outcome was the standardized mean differencein symptom scores at the end of follow-up pooled sepa-rately for Qigong and Tai Chi studies. The secondary outcomewas the standardized mean gain in symptom score (SMG)between pre-intervention and post-intervention pooled sep-arately for individual arms which included Qigong, TaiChi and each of the other control interventions includ-ing usual care. The standardized mean gain (SMG) wasgiven by:

SMG = X̄T2 − X̄T1

sp

,

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Table 1 Characteristics of included Qigong studies.

Reference Groups Population (studysample)

Duration DepressionScale

Baseline Follow-up

N (QG/CG) Mean (SD) N (QG/CG) Mean (SD)

Burini et al.(2006)27

QG: 3 sessions/week; 50 min/sessionCG: aerobic training, 3 sessions/week;50 min/session

Parkinson’s disease; age(mean + SD): 65.2 ± 6.5years; gender (m/f):9/17

7 weeks BDI 13/13 Median (IRQ):QG = 15 (0—29);CG = 10 (0—29)

11/11 Median(IRQ):QG = 11(6—35); CG = 11(1—27)

Chan et al.(2013)28

QG: self-healing Qigong; 60 min persession; two sessions per weekCG: usual care control

Fist year nursing andmidwifery students; age(range): 18—28 years;gender (m/f): 7/27

10weeks

DASS 21 18/16 Median (IQR):QG = 10 (2—26)CG = 8 (2—22)

18/16 Median (IQR):QG = 4 (0—14)CG = 2 (0—20)

Chan et al.(2013)29

QG: Wu Xing Ping Xing Gong; grouptraining: 120 min per group session,two group sessions per week and atleast 30 min per day for 5 weeks,followed by 12 weeks of home-basedtrainingCG: waiting-list control

With chronic fatiguesyndrome-like illness;age (mean + SD):42.5 ± 6.6 years; gender(m/f): 32/105

17weeks

HADS 72/65 QG = 9.1 (2.0)CG = 9.4 (2.2)

72/65 QG = 7.7 (3.2)CG = 9.8 (4.1)

Chen et al.(2008)30

QG: external Qigong therapy by healer1; 4—7 min per session; five to sixsessions in 3 weeksCG1: external Qigong therapy byhealer 2; 5—10 min per session; five tosix sessions in 3 weeksCG2: shame Qigong therapy; five to sixsessions in 3 weeks

With knee osteoarthritis;age (mean + SD):61.9 ± 8.63 years;gender (m/f): 30/76

3 weeks CES-D10 QG/CG1/CG2:45/12/49

QG = 35.6 (4.3)CG1 = 39.4 (6.6)CG2 = 32.8 (9.0)

QG/CG1/CG2:45/12/49

QG = 34.2 (3.1)CG1 = 36.7 (5.6)CG2 = 34.4 (4.7)

Chen et al.(2013)31

QG: Guo Lin New Qigong; Groupintervention: 40 min per groupsession, 5 group sessions per week;DVD with a recording of the qigongprogram also provided and encouragedto do home-based training whenparticipants did attend group session.CG: waiting-list standard care control

Women undergoingradiotherapy for breastcancer; age (mean + SD):45.0 ± 8.0 years; gender(f): 96

5—6weeks

CES-D20 49/47 QG = 13.1 (8.9)CG = 12.2 (9.2)

49/47 QG = 12.3 (8.2)CG = 11.6 (8.1)

Cheunget al.(2005)32

QG: Guolin Qigong, 2h/session/weekduring first 4 weeks, and 2hsession/month during 12 weeks followupCG: conventional exercise (stretching,walking and stepping),2 h/session/week during first 4 weeks,and 2 h session/month during 12weeks follow up.

Hypertension; age(mean + SD):54.2 ± 8.5 years; gender(m/f): 37/51

16weeks

BDI 47/44 NR 47/41 Mean change (se):QG = −1.9 (±0.8)CG = (se) = −2.2(±1.0)

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Table 1 (Continued)

Reference Groups Population (studysample)

Duration DepressionScale

Baseline Follow-up

N (QG/CG) Mean (SD) N (QG/CG) Mean (SD)

Chow et al.(2012)33

QG: Chan mi Qigong; 90 min persession/week in the first 8 weeksfollowed by 4 weeks home-basedpracticeCG: waislist control (usual care)

Healthy middle-agedadults; age (mean + SD):44.2 ± 11.03 years;gender (m/f): 23/45

12weeks

DASS 21 34/34 QG = 6.29(5.33)CG = 6.97 (5.93)

34/31 QG = 2.47 (3.38)CG = 6.65 (6.40)

Chung et al.(2010)34

QG: home based breathing training,10 min/time, 3 times dailyCG: weekly telephone support controlgroup, 5 min per session/week

With coronary heartdisease; age (mean + SD):71.59 ± 11.1 years;gender (m/f): 43/19

4 weeks BDI 33/39 QG = 16.61(7.35)CG = 19.44(8.14)

28/34 QG = 9.21 (6.04)CG = 21.03 (10.81)

Fang et al.(2008)35

QG: Eight-section Brocade Qigong:home-based; 1 h/time/day; 7days/week.CG: details, unknown

With type 2 diabetics;age (mean + SD):58.8 ± 8.11 years;gender (m/f): 18/27

2months

SymptomChecklist90

25/20 NRNR

25/20 QG = 0.4 (0.47)CG: 0.7 (0.53)

Kim et al.(2005)36

QG: relaxation breathing exercise,30 min daily/session, 7 days/weekCG: usual care control

With allogenichemopoietic stem celltransplantation; Age(mean + SD); 33.6 ± 7.4years; gender (m/f):17/18

6 weeks BDI 18/17 QG = 19.2 (1.9)CG = 18.4 (3.5)

18/17 QG = 8.4 (4.4)CG: 21.6 (7.2)

Smelsonet al.(2013)37

QG: external Qigong therapy byhealer; 15 min per session; two tothree sessions per weekCG: Sham Qigong therapy by healer;15 min per session; two to threesessions per week

Recently abstinentcocaine-dependentindividuals; age(mean + SD): 38.2 ± 10.8years; gender (m/f):97/4

2 weeks BDI 45/41 QG = 13.6 (7.0)CG = 11.9 (8.3)

45/41 QG = 3.7 (4.9)CG = 5.1 (5.6)

Stenlundet al.(2009)38

QG: 1 h/session, biweekly.CG: usual care control

With diagnosis ofburnout and exhaustionsyndrome; age(mean + SD); 40.4 ± 9.1years; gender (m/f):14/68

12weeks

HADS 41/41 Median (IQR):QG = 11 (8—12)CG = 10 (7—12)

33/35 Median (IQR):QG = 7 (5—12)CG = 8 (5—11)

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Thomaset al.(2012)39

QG: breathing training; consisted ofthree sessions, an initial 60 min smallgroup session followed by twoindividual sessions of 30—45 min; andencouraged to practice theseexercises for at least 10 min each day.Explanation of normal breathing andpossible effects of abnormal‘‘dysfunctional breathing’’ such asover-breathing, mouth breathing andupper chest breathing was provided.CG: asthma education control;consisted of three sessions, an initial60 min small group session followed bytwo individual sessions of 30—45 min

With asthma; median(interquartile range):46.0 (33.0—57.3(intervention group);46.0 (35.0—57.0)(control group); gender(m/f): 71/112

24weeks

HADS 94/89 NR 63/66 Mean change (95%confidenceinterval):QG = −0.31 (−0.72to 0.10)CG = 0.44 (−0.08to 0.94)

Tsang et al.(2003)40

QG: Eight-section Brocades Qigong, atleast 30 min daily home training plus 2group sessions/weekCG: basic rehabilitation activitiesincluding self-care training, remedialactivities, and educational programs,etc

Elderly with chronicphysical illnesses; age(mean + SD): 74.6 ± 8.97years; gender (m/f):26/24

12weeks

GDS 26/24 QG = 7.39(3.91)CG = 6.05 (3.40)

26/24 QG = 6.13 (4.14)CG = 5.16 (4.14)

Tsang et al.(2006)41

QG: Eight-section Brocades Qigong;30—45 min per session, 3 sessions perweek plus 15 min daily home-basedpracticeCG: newspaper reading group;30—45 min per session, 3 sessions perweek

With depression orobvious features ofdepression; aged 65 orabove; gender (m/f):16/56

16weeks

GDS NR QG = 5.17(2.75)CG = 6.50 (1.42)

34/48 QG = 3.19 (2.12)CG = 6.15 (1.46)

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Table 1 (Continued)

Reference Groups Population (studysample)

Duration DepressionScale

Baseline Follow-up

N (QG/CG) Mean (SD) N (QG/CG) Mean (SD)

Tsang et al.(2012)42

QG: Eight-section brocades; grouptraining: 45 min per group session, 3group sessions per weekCG: newspaper reading and discussioncomparison group; group intervention:45 min per group session, 3 groupsessions per week

Diagnostic depression;age (mean + SD):80.2 ± 5.1 years; gender(m/f): 12/26

12weeks

HRSD 21/17 QG = 7.8 (6.6)CG = 8.9 (6.3)

21/17 QG = 3.8 (3.6)CG = 6.8 (3.5)

Tsang et al.(2013)43

QG: Yan Chai Yi Jin Ten-SectionBrocades (Eight-section brocades + YiJin Jing); 60 min per session; twosessions per weekCG: newspaper reading program;60 min per session; two sessions perweek

Frail elders; age(mean + SD): 84.1 ± 6.0years; gender (m/f):29/87

12weeks

GDS 61/55 QG = 4.1 (3.1)CG = 4.4 (3.3)

61/55 QG = 4.3 (3.3)CG = 4.8 (3.5)

Yang et al.(2005)44

QG: Qi-therapy (external Qigong);20 min/session, biweeklyCG: usual care control

With chronic pain; age(mean + SD):72.59 ± 6.45 years;gender (m/f): 8/32

4 weeks Koreanversion ofthe Profileof MoodStates

20/23 QG = 11.26 ± 6.07CG = 10.10 ± 5.62

19/21 QG = 1.16 ± 1.74CG = 7.86 ± 5.08

QG = Qigong group; CG = control group; NR = no report; IQR = interquartile range.BDI = Beck Depression Inventory; GDS = Geriatric Depression Score; HADS = Hospital Anxiety and Depression Scale; DASS 21 = Depression Anxiety and Stress Scale 21; CES-D10 = Center forEpidemiological Study Depression Scale 10; HRSD = Hamilton Rating Scale of Depression.

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Table 2 Characteristics of included Tai Chi studies.

Reference Groups Population (study sample) Duration DepressionScale

Pre-treatment Post-treatment

N (TG/CG) Mean (SD) N (TG/CG) Mean (SD)

Cheng et al.(2012)45

TG: a seated 12-form Yangstyle Tai Chi; 60 min/session; 3sessions/weekCG1: Mahjong leisure activity;60 min/session; 3sessions/weekCG2: handicraft leisure controlactivity; 60 min/session; 3sessions/week

With at least moderatedepressive symptoms; age(mean + SD): 81.8 ± 6.3 years;gender (m/f): 12/24

12 weeks GDS TG/CG1/CG2:12/12/12TG = 9.25 (2.14)CG1 = 8.42(2.50)CG2 = 9.08(2.11)

TG/CG1/CG2:12/12/12TG = 7.75 (2.83)CG1 = 5.17(4.57)CG2 = 9.17(2.76)

Cheon et al.(2013)46

TG: Sun style TaiChi-for-arthritis program;50—65 min per session, threesessions per weekCG1: combined exerciseprogram including folkdancing, stepping andelastic-bank exercisesCG2: usual care control group(no intervention)

With mild-to-moderateParkinson’s Disease; age(mean + SD): 64.3 ± 7.2 years;gender (f): 23

8 weeks BDI TG/CG1/CG2:9/7/7

TG = 23.4 (10.2)CG1 = 27.6(12.3)CG2 = 23.2(18.1)

TG/CG1/CG2:9/7/7

TG = 20.3 (6.3)CG1 = 26.1(11.2)CG2 = 29.3(12.7)

Chou et al.(2004)47

TG: Yang style Tai Chi;45 min/session, 3 sessions perweekCG: waiting list usual carecontrol

With major depression ordysthymia; age (mean + SD):72.6 ± 4.2 years; gender (m/f):7/7

12 weeks CES-D 20 7/7 TG = 32.0 (9.9)CG = 32.7 (8.7)

7/7 TG = 15.3 (9.8)CG = 39.1 (9.7)

Frye et al.(2007)48

TG: Yang style Tai Chi;60 min/session, 3sessions/weekCG1: low impact exerciseintervention (traditionalWestern exercise);60 min/session, 3sessions/weekCG2: non-exercise control

Sedentary older people; age(mean + SD): 69.2 ± 9.26 years;gender (m/f): 30/54

12 weeks CES-D 20 TG/CG1/CG2:31/30/23

TG = 11.1 (7.98)CG1 = 10.1(5.70)CG2 = 9.1 (6.83)

TG/CG1/CG2:23/28/21

TG = 9.6 (8.87)CG = 8.7 (8.80)CG = 10.6 (8.82)

Lam et al.(2010)49

TG: 24 forms simplified Tai Chi;at least 30 min daily; at least 3sessions/weekCG: stretching and toningexercise; at least 30 min daily;at least 3 sessions/week

With either a Clinical DementiaRating (CDR 0.5) oramnestic-MCI; age (mean + SD):77.8 ± 6.5 years; gender (m/f):92/297

20 weeks CDS 171/218 TG = 0.9 (1.8)CG = 0.8 (1.8)

135/194 TG = 0.7 (0.9)CG = 0.6 (0.9)

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Table 2 (Continued)

Reference Groups Population (study sample) Duration DepressionScale

Pre-treatment Post-treatment

N (TG/CG) Mean (SD) N (TG/CG) Mean (SD)

Lavretskyet al.(2011)50

TG: Tai Chi Chih; 2 h/weekCG: health education control;2 h/week

With major depression; age(mean + SD): 70.6 ± 7.2 years;gender (m/f): 28/45

10 weeks HDRS 36/37 TG = 17.8 (2.0)CG = 17.0 (1.6)

33/35 TG = 5.1 (3.5)CG = 6.7 (4.4)

Taylor-Piliaeet al.(2014)51

TG: Yang style Tai Chi24-posture short-form; 60-misessions, three sessions perweekCG1: sliver sneakers (a fitnessgroup program with differenttypes of exercise, e.g.aerobics, strength and range ofmovement, water aerobics,yoga); 60-min sessions, threesessions per weekCG2: control group: receivedwritten materials andresources for participating incommunity-based physicalactivity, plus weekly phone callto inquire of their health statusto provide individual attention

Old stroke survivors; age(mean + SD): 69.9 ± 10.0 years;gender (m/f): 77/68

12 weeks CES-D 20 TG/CG1/CG2:53/44/48

TG = 14.3 (9.8)CG1 = 11.1 (7.4)CG2 = 15.7(11.9)

TG/CG1/CG2:53/44/48

TG = 14.0 (9.6)CG1 = 11.4 (9.6)CG2 = 13.6(10.2)

Wang et al.(2009)52

TG: Yang style Tai Chi; 60-minsessions twice weekly; plus atleast 20-min home basedtraining daily with DVDprovidedCG: the attention controlintervention (the wellnesseducation and stretchingprogram): two 60-min classsessions per week

Symptomatic tibiofemoral kneeosteoarthritis; age (mean + SD):65.5 ± 7.6 years; gender (m/f):10/30

12 weeks CES-D 20 20/20 TG = 13.6 (11.7)CG = 9.3 (9.2)

20/20 Mean change(CI%):TG = −7.40(−10.88,−3.92)CG = −0.70(−4.18, 2.78)

Wang et al.(2010)53

TG: Yang style Tai Chi;50 min/session, 1 session/weekCG: rehabilitation(non-resistancetraining + resistance training)control; 80 min/session, 1session/week

With Cerebral vasculardisorder; age (mean + SD):77.1 ± 11.0 years; gender(m/f): 9/25

12 weeks GHQ-60severedepressionscore

17/17 TG = 2.1 (2.2)CG = 1.3 (1.7)

16/13 TG = 0.7 (0.8)CG = 1.2 (1.5)

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igongand

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s525

Yeh et al.(2010)54

TG: Yang style Tai Chi; 60 minper session, 2 sessions/week;plus 3 times home basedtrainingCG: usual care control

Moderate to severe ChronicObstructive PulmonaryDisease; age (mean + SD):66 ± 6 years; gender (m/f): 6/4

12 weeks CES-D 20 5/5 Median (IQR):TG = 14 (11—46)CG = 12 (2—17)

5/5 Median (IQR):TG = 5 (1—27)CG = 8 (0—17)

Yeh et al.(2013)55

TG: Cheng Man-Ch’ing’s Yangstyle; 60 min per session, twosessions per week; providedwith a 35 min videotape thatreviewed the exercisespresented in class and wasencouraged to practice athome at least 3 times per weekCG: aerobic exercisecomparison group; 60 min persession, two sessions per week;provided with a 35 minvideotape that reviewed theexercises presented in classand was encouraged topractice at home at least 3times per week

With Heart Failure withPreserved Ejection Fraction;age (mean + SD): 66.0 ± 12.0years; gender (m/f): 8/8

12 weeks PMSD 8/8 TG = 4.0 (2.0)CG = 1.3 (2.0)

8/8 TG = 2.3 (2.0)CG = 3.0 (3.0)

Yeung et al.(2012)56

TG: Yang style Tai Chi; 60 minper session, biweekly; plushome based practice at least 3sessions per weekCG: waitlist control (usualcare)

With major depressivedisorder; mean + SD): 55 ± 10years; gender (m/f): 9/30

12 weeks HRSD 26/13 TG = 18 (3)CG = 17 (3)

25/13 Mean change(SD): TG = 5.2(5.1)CG = 4.5 (2.4)

TG = Tai Chi group; CG = control group; IQR = interquartile range.GDS = Geriatric Depression Score; CDS = Cornell Depression Score; HRSD = Hamilton Rating Scale of Depression; CES-D20 = Center for Epidemiological Study Depression Scale 20; BDI = BeckDepression Inventory; PMSD = Profile of Mood States Depression.

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526 X. Liu et al.

Table 3 Quality checklist (primary outcome — analytic two-arm study).

Item Questions Score

1 = Yes/notapplicable,0 = no/unclear

Design bias1 What was the type of design?

a) Randomized and allocation concealed — 3 pointsb) Randomized only — 2 pointsc) Prospective cohort — 1 pointd) Retrospective cohort or case control — 0 point[note of b): 1. Was the study described as randomized (this includes wordssuch as randomly, random, and randomization)? Yes = 1, No = 02. Was the method used to generate the sequence of randomizationdescribed and appropriate (table of random numbers,computer-generated, etc)? Yes = 1, No = 0]

2 Was the duration of active treatment appropriate for the demonstration ofstudy outcome (e.g. ≥3 months for depressive symptoms)?

Selection bias3 Did the inclusion/exclusion criteria remain consistent across the

comparison groups of the study?4 Was the strategy for recruitment into the study the same across

comparison groups (e.g. not from same populations or both groups werenot recruited over the same time period)?

5 Was the interval between the start of intervention and outcome the sameacross comparison groups, or if different, were appropriate analyses usedto equalize this (e.g. time-to-event analyses)?

6 Was attrition <20%, or if not, was follow-up done for these subjects toensure their loss was not related to outcome?

Information bias7 Were the outcomes of interest in the study pre-specified?8 Were reproducible measures (clear name of predefined scale or clear

details of non-predefined scale were presented) of study outcomesimplemented in the same way across comparison groups?

9 Were the outcome assessors blinded to the nature of intervention orcontrol (e.g. Qigong, acupuncture or usual medical care)?

10 Were the subjects blinded to the nature of intervention or control (e.g.Qigong, acupuncture or usual medical care)?

11 Apart from blinding, were any other safeguards described and used forassuring the reliability of study outcomes (e.g. any of the validatedinstruments, duplicated measurement, independent assessment)?

12 Were data assessed and recorded in the same way for both comparisongroups and across time points?

13 Were interventions/exposures clearly defined (all essential componentswere described) and implemented in the same way across both studygroups?

Confounding bias14 Were the groups similar at baseline in key confounding variables or if not

were steps taken to achieve comparability of key confounders (e.g.through matching, stratification, interaction terms, multivariate analysis,or other statistical adjustment such as instrumental variables)?

Analytical bias15 Were effect sizes based on the data available at post assessment or

pre-defined subgroups rather than a post hoc portion of the data?16 Was intention-to-treat analyses conducted for the outcome of interest?17 Were all data available (i.e. they did not need to be estimated from

results)?

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A systematic review and meta-analysis of the effects of Qigong and Tai Chi for depressive symptoms 527

Table 4 Quality checklist (Secondary outcome — single arm).

Item Questions Score

1 = Yes,0 = no/unclear

Design bias1 Was the sample community-based?2 Was the duration of active treatment appropriate for the demonstration of study

outcome (≥3 months for depressive symptom)?Selection bias3 Was attrition <20%, or if not, was follow-up done for these subjects to ensure

their loss was not related to outcome?Information bias4 Were the outcomes of interest in the review pre-specified?5 Were study outcomes clearly defined (clear name of predefined scale or clear

details of non-predefined scale were presented)?6 Were the outcome assessors blinded to the nature of intervention (e.g. Qigong,

acupuncture or usual medical care)?7 Apart from blinding, were any other safeguards described and used for assuring

the reliability of study outcomes (e.g. any of the validated instruments,duplicated measurement, independent assessment)?

8 Were data assessed and recorded in the same way at two time points?9 Were interventions clearly defined (all essential components were described)?Confounding bias10 Did researchers record and adequately control for any impact from change to

concurrent intervention or exposure that could affect outcome (e.g. medicationfor outcome of interest, etc)?

Analytical bias11 Were effect sizes based on the data available at post assessment or pre-defined

subgroups rather than a post hoc portion of the data?12 Was intend-to-treat analyses conducted for the outcome of interest?13 Were all Mean Gain and SE/CI or Mean and SD available (i.e. they did not need to

be estimated from median/range or median/IQR)?

where

sp =√

(s2T1 + s2

T2)2

and whose standard error was given by:

SEsmg =√

2 (1 − r)n

+ SMG2

2n

where Sp, ST1, and ST2 are the standard deviations of groupspooled, the pre-intervention and the post-interventionresults, respectively. The standard deviations were calcu-lated from either the confidence intervals or the standarderror and sample size when standard deviations were notgiven. In instances where the median and interquartile rangewere presented, the median was used as an approximationof the mean and the standard deviation was estimated bydividing the interquartile range by 1.35.20 Where median andrange were available, the approach given by Hozo et al.21

was used.Pooled estimates were obtained after bias adjustment.

The quality scores were used to redistribute inverse variance

weights based on study ranking of safe-guards used againstbias using a quality-effects (QE) model.22,23 Therefore,weight redistribution occurred in favor of the studies withhigher methodological quality ranking, which contributedto a higher weighting of these studies toward the overalleffect size.23 It should be emphasized that these empir-ical studies confirm that the gain in estimator efficiency(in terms of mean squared error reduction) far outweighany errors due to subjectivity of the quality assessment.24

Nevertheless, the random effects results were also com-puted and presented (in the online material) for comparisongiven that some statisticians still raise concerns over theuse of summary quality scores. Heterogeneity was assessedby the Cochran’s Q test, the I2 index, and the Tau-squaredstatistic (�2), as well as through graphical evaluation ofthe forest plot. Heterogeneity was defined as a Cochran Qtest p-value of less than 0.1, or a �2 value of greater thanzero.25

A sensitivity analysis was conducted to determine thedegree to which the main findings vary depending on theselection criteria of studies included in the meta-analysis.These selection criteria included calendar period of study(the Qigong and Tai Chi studies were arbitrarily split bytime frame of the study — cutoff at 2010—2011 for more

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528 X. Liu et al.

Table 5 Sensitivity analysis for the primary outcome results by time frame, study sample size, intervention duration, severityof depressive symptoms, co-morbidities status and mean age.

Outcome andestimate, I2

Altered inclusion/exclusioncriteria

Estimate for altered criteria(Cohen’s d, 95% CI)

Heterogeneity and datasets inthe analysisI2, % (N)

Qigongd = −0.48(−0.83 to−0.12), 84%

Time frame of study<2010≥2010

−0.54 (−1.27 to 0.19)−0.44 (−0.76 to −0.12)

90 (8)71 (8)

Study sample size<60≥60

−0.71 (−1.40 to −0.03)−0.41 (−0.80 to −0.02)

85 (7)86 (9)

Duration<3 months≥3 months

−0.39 (−0.97 to 0.19)−0.55 (−1.01 to −0.09)

87 (9)83 (7)

Severe depressive symptoms**

YesNo

−0.33 (−0.75 to 0.09)−0.66 (−1.28 to −0.05)

80 (9)88 (7)

Co-morbiditiesYesNo

−0.40 (−0.91 to 0.11)−0.59 (−1.11 to −0.08)

86 (10)82 (6)

Mean age ≥ 60YesNo

−0.52 (−1.17 to 0.13)−0.44 (−0.83 to −0.05)

90 (8)76 (8)

Tai Chid = −0.07(−0.44 to 0.31),58%

Time frame of study<2011≥ 2011

0.07 (−0.74 to 0.87)−0.22 (−0.52 to 0.08)

71 (5)12 (5)

Study sample size<50≥50

−0.32 (−1.06 to 0.42)0.00 (−0.21 to 0.21)

67 (6)21 (4)

Duration<3 months≥3 months

−0.48 (−0.92 to −0.04)0.00 (−0.40 to 0.40)

0 (2)56 (8)

Severe depressive symptoms**

YesNo

−0.62 (−1.67 to 0.43)0.06 (−0.11 to 0.23)

72 (3)0 (7)

Co-morbiditiesYesNo

0.07 (−0.14 to 0.28)−0.50 (−1.17 to 0.17)

8 (6)66(4)

Mean age ≥60***

** Severe depressive symptoms were defined based on the cutoff in each symptom scale assessed at baseline (Yes = study sample withsevere depressive symptoms, No = study sample with mild depressive symptoms). These cutoffs were as follows for the purposes of thisreview: BDI < 10, BDI-II < 14, GDS < 6, HADS < 8, PMS < 35, DASS-21 < 5, CES-D-10 < 10, CES-D-20 < 16, CSDD < 11, GHQ-60 < 12, HAM-D < 8 anddepression status inventory <50.*** All datasets had subjects with mean age ≥60 years.

recent studies), study sample size (50—60 subjects definedas small samples), severity of depressive symptoms at base-line (based on the recommended cutoff for each scale fordepression given as a footnote to Table 5), co-morbidity sta-tus (presence of a medical condition other than depression),and elderly status (mean age ≥ 60 years). The sensitivityanalysis determined if these selection criteria had a sub-stantial impact on the pooled standardized mean gain insymptom score.

Publication bias was examined by visual inspection ofthe funnel plot, but given that its visual appearance canbe problematic, a Doi plot was also used to graphicallyevaluate publication bias. The latter is a plot of the out-come of interest against the absolute value of the z-scorederived from the studies and provides a better visual assess-ment of asymmetry than the funnel plot.26 The results ofall analyses were considered statistically significant if the95% confidence intervals did not include zero. The data was

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A systematic review and meta-analysis of the effects of Qigong and Tai Chi for depressive symptoms 529

analyzed using MetaXL software version 2.0 for Windows(www.epigear.com).

3. Results

3.1. Search results

In total, 811 studies were located after excluding dupli-cations (Fig. 1). Abstracts were reviewed for selection ofthe studies whose full text were to be retrieved and finallyeighteen Qigong27—44 and twelve Tai Chi studies45—56 wereincluded for analysis after excluding irrelevant studies andstudies with unclear data whose authors did not respondto a request to clarify the problem (Fig. 1). Two Qigongstudies28,36 and two Tai Chi studies52,53 were excluded fromthe standardized mean difference analysis because of non-extractable data for this outcome.

3.2. Characteristics of included studies

All included studies were randomized controlled trials (seeTables 1 and 2). The Qigong intervention period across allstudies ranged between 10 days and 24 weeks. These weredelivered across all studies in between 1 and 21 sessionsper week (3 sessions daily) of between 5 and 120 min dura-tion per session. The interventions included Guolin Qigong,Guolin New Qigong, Eight-section Brocades Qigong, Eight-section Brocades plus Yi Jin Jing Qigong, Chan Mi Qigong,External Qigong therapy, Wu Xing Ping Gong, breathing train-ing and two studies where Qigong type was not specified.Similarly, the Tai Chi intervention period ranged from 8 to20 weeks with 1 to at least 3 sessions per week of 30—120 minduration per session. Tai Chi Interventions were Yang styleand Sun style Tai Chi.

3.3. Participants

In the included studies, there were 1425 participants (535males and 890 females) given Qigong and 903 participants(288 males and 615 females) given Tai Chi with a total of2328 participants (823 males and 1505 females). Partici-pants in the Qigong studies had a wide variety of differentco-morbid health conditions which included Parkinson’s dis-ease, hypertension, coronary heart disease, type 2 diabetes,allogenic haematopoietic stem cell transplantation, burnoutand exhaustion syndromes, chronic pain, asthma, depres-sion and osteoarthritis. In some cases subjects were healthymiddle-aged adults. Participants in the Tai Chi studies alsohad a wide variety of different co-morbid health condi-tions including dementia, cerebral vascular disorder, chronicobstructive pulmonary disease, and osteoarthritis.

3.4. Quality of the studies

When assessing the Cohen’s d outcome, the main qualitydeficiencies in more than half of the Qigong studies includedwere (1) the allocation of randomization results was not con-cealed; (2) the outcome assessors were not blinded to thenature of intervention; (3) the subjects were not blinded tothe nature of intervention or control; (4) the groups were

not similar at baseline in key confounding variables or stepswere not taken to achieve comparability of key confounders;(5) intention-to-treat analyses were not conducted for theoutcome of interest. Similarly, the main quality deficienciesin more than half of the Tai Chi studies included were (1) theallocation of randomization results was not concealed; (2)the subjects were not blinded to the nature of interventionor control; (3) the interventions were not clearly defined; (4)the groups were not similar at baseline in key confoundingvariables or steps were not taken to achieve comparabilityof key confounders.

When assessing the SMG outcome in individual studyarms, the main overall quality deficiencies in more thanhalf of the studies included (1) the outcome assessors werenot blinded to the nature of intervention; (2) researchersdid not record and adequately control for any impact fromchange to concurrent intervention or exposure that couldaffect outcome; and (3) intention-to-treat analyses were notconducted for the outcome of interest.

3.5. Quantitative synthesis

3.5.1. Primary outcomeAcross RCTs, the effect magnitude ranged between −2.23and 0.45 for Qigong and between −2.44 and 0.47 for TaiChi (Fig. 2). The only significant overall effect (Fig. 2) wasfound for the Qigong interventions (d −0.48, 95% CI −0.83to −0.12). There was no significant overall effect seen withTai Chi (d −0.07, 95% CI −0.44 to 0.31).

3.5.2. Secondary outcomeFig. 3 shows that the only overall effect in the reductionof depressive symptoms was found for the Qigong inter-ventions (SMG −0.52, 95% CI −0.79 to −0.26). There wasno significant overall effect seen with Tai Chi, usual care,other exercises, education and the ‘miscellaneous’ cate-gory (Fig. 3). Significant heterogeneity was seen with theQigong, Tai Chi, usual care, other exercises and educationinterventions.

3.6. Sensitivity analyses

Table 5 shows the results of the sensitivity analysis for theprimary outcome. The Tai Chi studies showed a strongereffect when studies were smaller, more recent, shorterduration, had more severe symptoms at baseline and did nothave co-morbidities. There was no clear pattern discernablefor the Qigong studies.

There was gross evidence of publication bias favoring thepositive studies of both Qigong and Tai Chi studies. The Doiand funnel plots (Figs. 4 and 5) demonstrated asymmetrysuggesting that either there was gross heterogeneity suchthat small studies had systematically larger effects thanlarger studies or that those with negative outcomes did notget published and were therefore missing.

4. Discussion

The novel finding from the present review was thatQigong demonstrated a significant effect on lessening the

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530 X. Liu et al.

Fig. 1 Flow of literature extraction.

Fig. 2 Effect sizes for standardized mean difference in depressive symptoms at the end of follow-up. (a) Qigong. (b) Tai Chistudies.

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A systematic review and meta-analysis of the effects of Qigong and Tai Chi for depressive symptoms 531

Fig. 3 Standardized mean reduction in depressive symptoms from pre- to post-follow-up in single arms of (a) Qigong. (b) Tai Chi.(c) Usual care. (d) Other excises. (e) Education. (f) Miscellaneous groups.

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532 X. Liu et al.

Fig. 4 Qigong studies: Doi (left) and funnel (right) plots ofbetween-group outcomes demonstrating gross asymmetry ofboth favoring stronger effects.

Fig. 5 Tai Chi studies: Doi (left) and funnel (right) plots ofbetween-group outcomes demonstrating gross asymmetry ofboth favoring stronger effects.

severity of depressive symptoms, but not Tai Chi. In singlearm pre-post evaluations, usual care, other conventionalexercises or education were no better than Tai Chi. Thissuggests that the traditional Qigong mind-body movementtherapy may be more effective than the martial arts basedTai Chi exercise and conventional exercises in reducingdepressive symptoms. The current review did not supportthe conclusions of two prior reviews published in 201012

and 201313 suggesting that Tai Chi was an effective inter-vention for depressive symptom scores as the review foundthat Tai Chi studies did not show significant improvement indepressive symptom scores in study participants reviewed.However, it should be noted that the majority of Qigonginterventions were <3 months and majority of Tai Chiinterventions were > 3 months, which could explain theQigong-Tai Chi difference if duration is an important variableand effectiveness drops off. However, the Qigong studieswith short intervention duration showed a similar magnitudeof effect as those with longer intervention duration, sug-gesting that the differences may not entirely be explainedby duration of intervention. In addition, Qigong (as a medi-cal exercise) focuses more on ‘inside’ energy flow than TaiChi (as a martial arts) and this may partially explain thedifferences in efficacy for reduction of depressive symptomseverity.

There were a wide variety of participants in terms ofdemographic characteristics and health conditions. In addi-tion, study methodology such as sample size and style anddose of exercise interventions (including length, trainingsessions and time) varied across the studies. Significant het-erogeneity was detected in Qigong, Tai Chi, usual care, otherexercises and education. In terms of sensitivity analysis, TaiChi studies conducted at later time periods demonstratedlarger magnitudes of effect sizes on depressive symptomsthan those in less recent years, suggesting that the researchmethodology might have been improved with time. TheTai Chi studies with small sample sizes showed higher

magnitudes of effect sizes than those with larger samplesizes, suggesting the studies with larger samples may havebeen more rigorously designed and executed. There werealso larger effects for Tai Chi when co-morbidities wereabsent. Such a differential did not seem to be presentwith the Qigong studies. In addition, the Doi plots demon-strated gross asymmetry, suggesting that the magnitude ofthe effect seen for both Tai Chi and Qigong may partly be aresult of publication bias and may not reflect its real poten-tial effect.

The strengths of the present review were analyses witha systematic and transparent literature extraction, stan-dardized inclusion and study evaluation criteria and qualityassessment as an essential part of the meta-analysis. Indeed,this was the first review on the effects of Qigong and Tai Chion depressive symptoms that performed a stringent qualityassessment that was a major part of this quality adjustedmeta-analysis, and stratification by quality score was there-fore unnecessary given its limitations.57 The strength ofthis meta-analysis is therefore the use of tangible infor-mation from studies to account for heterogeneity. Thisaddresses the numerous problems associated with using therandom effects model in meta-analysis, with particular ref-erence to the interpretation of results and practicality ofits assumptions.58—60 Finally, limitations of this review werethat it did not include unpublished studies and could notassess the dose response effect as most of the included stud-ies had no or limited follow-up. In addition, the effects ofstyles of intervention and environment and finally genderdifference across studies could not be assessed. However,this heterogeneity increases the external validity of theresults.

In conclusion, Qigong appears to be effective in improvingdepressive symptoms but not Tai Chi. Pre-post evaluation ofsingle arm control groups which included usual care, otherconventional exercises and education revealed no effectakin to Tai Chi arm. However, these results are not conclusivegiven the evidence of publication bias and overall poor qual-ity of the reviewed studies, and therefore should be viewedcautiously. Further studies with large sample size, longerfollow-up and cost-effectiveness analyses are required toconfirm the clinical effectiveness, cost-effectiveness andmaintenance of benefits with Qigong.

Conflict of interest statement

All authors have no financial disclosure.

Acknowledgements

The Australian National Heart Foundation and the NationalDepression Initiative, beyondblue grant G 088 4034 sup-ported preparation of this manuscript. We also thank threeanonymous referees for their very helpful comments.

Appendix A. Supplementary data

Supplementary data associated with this article can befound, in the online version, at http://dx.doi.org/10.1016/j.ctim.2015.05.001.

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A systematic review and meta-analysis of the effects of Qigong and Tai Chi for depressive symptoms 533

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