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'Third wave' cognitive and behavioural therapies versus other psychological therapies for depression

  1. Vivien Hunot1,
  2. Theresa HM Moore2,
  3. Deborah M Caldwell2,
  4. Toshi A Furukawa3,
  5. Philippa Davies2,
  6. Hannah Jones4,
  7. Mina Honyashiki5,
  8. Peiyao Chen5,
  9. Glyn Lewis6,
  10. Rachel Churchill1,*

Editorial Group: Cochrane Depression, Anxiety and Neurosis Group

Published Online: 18 OCT 2013

Assessed as up-to-date: 1 FEB 2013

DOI: 10.1002/14651858.CD008704.pub2


How to Cite

Hunot V, Moore THM, Caldwell DM, Furukawa TA, Davies P, Jones H, Honyashiki M, Chen P, Lewis G, Churchill R. 'Third wave' cognitive and behavioural therapies versus other psychological therapies for depression. Cochrane Database of Systematic Reviews 2013, Issue 10. Art. No.: CD008704. DOI: 10.1002/14651858.CD008704.pub2.

Author Information

  1. 1

    University of Bristol, Centre for Academic Mental Health, School of Social and Community Medicine, Bristol, Avon, UK

  2. 2

    University of Bristol, School of Social and Community Medicine, Bristol, UK

  3. 3

    Kyoto University Graduate School of Medicine / School of Public Health, Departments of Health Promotion and Behavior Change and of Clinical Epidemiology, Kyoto, Japan

  4. 4

    Institute of Mental Health, The University of Nottingham, Division of Psychiatry, Nottingham, UK

  5. 5

    Kyoto University Graduate School of Medicine / School of Public Health, Department of Health Promotion and Human Behavior, Kyoto, Japan

  6. 6

    UCL, Mental Health Sciences Unit, London, UK

*Rachel Churchill, Centre for Academic Mental Health, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol, Avon, BS8 2BN, UK. rachel.churchill@ccdan.org. rachel.churchill@bristol.ac.uk.

Publication History

  1. Publication Status: New
  2. Published Online: 18 OCT 2013

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Characteristics of included studies [ordered by study ID]
Dimidjian 2004

MethodsDesign: RCT, parallel design
Study duration: 16 weeks
Follow-up: none


ParticipantsSample size: 138 individuals eligible and agreed to participate    

Recruitment: media advertisements and referrals from local agencies/word of mouth

Inclusion criteriadiagnostic classification criteria: DSM-IV diagnosis made using SCID-I

Inclusion criteriarating scales: HRSD score ≥ 14 and BDI score ≥ 20

Included disorders: major depressive disorder

Gender: 66% of sample women

Mean age: 39.9 years (SD 10.97)

Country/Ethnicity: conducted in USA: 85.5% white

Pharmacotherapy during the study: one group randomly assigned to receive antidepressant treatment


InterventionsBehavioural activation

Intervention: BA condition an expanded version of the approach used in the component analysis study by Jacobson et al (1996). Centrality of patterns of avoidance and withdrawal highlighted, and increased activity presented as a strategy to break the cycle. Specific behaviourally focused activation strategies included self-monitoring, structuring and scheduling daily activities, rating pleasure/accomplishment and exploring different behaviours. Expanded model also included behavioural strategies for targeting rumination, understanding the function of ruminative thinking and moving attention away from the content of ruminative thoughts towards direct, immediate experience. Participants received a maximum of 24 individual 50-minute sessions over 16 weeks, with sessions generally held twice weekly for the first 8 weeks and once weekly for the next 8 weeks

Therapists: BA provided by two licensed psychologists and a licensed clinical social worker, who had been in clinical practice for an average of 7 years. Therapists received individual off-site supervision via telephone from two of the trial authors

Cognitive therapy

Intervention: CT condition provided in a manner consistent with standard CT for depression. Three broad classes of intervention included targeting behavioural dysfunction, situation-specific cognitive distortions and underlying dysfunctional beliefs. CT also included the full range of BA strategies outlined in CT texts for depression, but not those outlined as part of the expanded BA model. Participants received a maximum of 24 individual 50-minute sessions over 16 weeks, with sessions generally held twice weekly for the first 8 weeks and once weekly for the next 8 weeks

Therapists: CT provided by three licensed psychologists, who had been in clinical practice for an average of 14 years. Two had extensive training in CT before the outset of the trial, and the third had received specialised training in CT. Two study authors provided individual supervision off-site via telephone

Antidepressant medication

ADM condition administered triple-blind for first 8 weeks of the trial, after which the blind was broken and only evaluators were kept blind to the treatment condition. Participants prescribed paroxetine on a flexible schedule. Participants seen weekly for first 4 weeks, and then bi-weekly

Placebo

PLA condition administered triple-blind for first 8 weeks of the trial, after which participants offered their choice of treatment at study expense


OutcomesHRSD

BDI-II


NotesAuthors separated the sample into two groups of high and low depression severity on the basis of scores on the pretreatment HRSD (high severity ≥ 20, low severity≤ 19) because of potential problems with multicollinearity associated with including both the dichotomous severity variable (based on the HRSD) and pretreatment severity (continuous form of BDI-II or HRSD) as the first outcome measure in the same analysis. For purposes of including continuous data in the meta-analyses, high and low severity means and SDs entered separately, in accordance with figures reported in the paper

Only data from BA and CT arms used


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskParticipants assigned to one of four acute treatment conditions using a computer-generated randomisation list

Allocation concealment (selection bias)Low riskParticipants assigned to treatment conditions by the participant coordinator

Blinding of participants and personnel (performance bias)
All outcomes
High riskNot possible to blind participants and clinicians in CT and BA conditions. ADM and placebo conditions administered blind to participants for first part of study only

Blinding of outcome assessment for observer-rated scales (detection bias)Low riskEvaluators blind to participants' treatment condition and supervised weekly to prevent rater drift (page 661, col 1, para 4)

Incomplete outcome data (attrition bias)
All outcomes
Low riskTreatment differences for categorical response and remission conducted with the full ITT sample, using LOCF. Attrition similar in BA and CT groups, and reasons for attrition varied/mostly provided (page 659, col 2, para 2)

Selective reporting (reporting bias)Unclear riskNo study protocol available—insufficient information to allow an assessment

Researcher allegiance and other conflicts of interest (financial or other)Unclear riskExpanded BA model developed at the University of Washington, and CT supervisors off-site (page 668, col 2, para 1)

Therapist allegiance and other conflicts of interest (financial or other)Low riskBA and CT therapists had declared allegiance to their respective therapies

Therapist qualificationsLow riskBA and CT therapists similarly qualified and experienced in their respective approaches

Treatment fidelityLow riskTherapy sessions audiotaped, and adherence assessed by 5 undergraduate raters blind to the treatment condition and trained to use the CSPRS, modified to accommodate BA (page 661, col 2, para 2). No competency ratings for BA therapists provided (page 668, col 2, para 2)

Other biasUnclear riskInsufficient information provided

Zettle 1984

MethodsDesign: RCT of parallel design
Study duration:12 weeks
Follow-up: 2 months after end of treatment


ParticipantsSample size: 25 individuals eligible for the study, of whom 19 agreed to participate    

Recruitment: GP and O/P referrals, media advertisements

Inclusion criteria—diagnostic classification criteria : not stated

Inclusion criteria—rating scales: BDI score ≥ 20, MMPI Depression Scale T score ≥ 70/score greater than T scores on psychasthenia and hysteria scales, HRSD score ≥ 14

Included disorders: assessed as 'clinically depressed'

Gender: female participants only

Mean age: 40.39 years

Country/Ethnicity: conducted in the USA; no information provided on ethnicity of participants

Pharmacotherapy during the study: before initiation of treatment, participants required to verify that they were not taking antidepressants or tranquilising medications


InterventionsCT: cognitive restructuring plus distancing (assigned to 2 groups—with and without homework)

Intervention: CCT used full complement of therapeutic procedures and strategies common to CT, including distancing, cognitive restructuring and behavioural hypothesis testing. Distancing procedures included the use of similes, reattribution techniques and alternative conceptualisations. Participants received 12 individual weekly sessions lasting approximately 1 hour

Therapists: therapy provided by first author, who was completing an internship at the Center for Cognitive Therapy in Philadelphia. Supervision arrangements not reported

CT: cognitive restructuring alone (assigned to 2 groups—with and without homework)

Intervention: condition different from CCT in the absence of any distancing procedures. Participants received 12 individual weekly sessions lasting approximately 1 hour

Therapists: therapy provided by first author, who was completing an internship at the Center for Cognitive Therapy in Philadelphia. Supervision arrangements not reported

Comprehensive distancing (assigned to 2 groups—with and without homework)

Intervention: condition derived from a behavioural view of cognitive activity (Hayes 1987), based on three key themes that efforts to change depressive thoughts evoke the very thoughts to be eliminated, that depressive thoughts put forward as reasons for dysfunctional actions are merely more behaviour, and that treating depressive thoughts as behaviour in context makes it possible to behave more effectively despite the continued presence of negative thinking. Participants received 12 individual weekly sessions lasting approximately 1 hour

Therapists: therapy provided by first author, who was a doctoral level graduate student in psychology, completing an internship at the Center for Cognitive Therapy in Philadelphia. Supervised by Steven Hayes


OutcomesBDI

MMPI-D

HRSD

Automatic Thoughts Questionnaire

Dysfunctional Attitude Questionnaire

Pleasant Events Schedule (Activity Level, Reinforcement Potential and Obtained Reinforcement)


NotesFor the purposes of conducting analyses, CT plus distancing and CT without distancing combined into a single CT approach


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskNo information provided

Allocation concealment (selection bias)Unclear riskNo information provided

Blinding of participants and personnel (performance bias)
All outcomes
High riskNot possible to blind participants and clinicians in a psychological therapy trial

Blinding of outcome assessment for observer-rated scales (detection bias)Low riskParticipants interviewed by an independent advanced graduate student who was blind to treatment assignment (page 37, para 4). Interviews audiotaped and rated on the HRSD by another advanced graduate student, who was also blind to treatment assignment, to obtain a measure of interrater agreement (page 38, para 1)

Incomplete outcome data (attrition bias)
All outcomes
Low riskOnly one participant did not complete treatment

Selective reporting (reporting bias)Unclear riskNo study protocol available—insufficient information to make an assessment

Researcher allegiance and other conflicts of interest (financial or other)High riskSteve Hayes, who developed the comprehensive distancing (early version of ACT) manual, served as chairperson for author's dissertation and was supervisor and major advisor throughout first author's doctoral training (pages iii and 213)

Therapist allegiance and other conflicts of interest (financial or other)Unclear riskFirst author served as therapist for all six treatment conditions. Postsession questionnaire administered at end of each treatment session to check for differential bias between conditions. Findings not reported apart from statement in discussion that results of postsession questionnaire suggested that therapist bias did not account for differential treatment effects (page 105, para 2)

Therapist qualificationsHigh riskTherapist was doctoral level graduate student in psychology completing internship at the Center for Cognitive Therapy during course of study. Several years of clinical training and experience, with licensed psychological associate (page 213, para 2)

Treatment fidelityUnclear riskRandom third of all treatment sessions audiotaped and reviewed later by panel of four independent judges, who were familiar with treatment manuals but were blind to each treatment condition. 83% of tapes correctly classified (page 56, para 1). No fidelity scales used

Other biasHigh riskAn attendance fee given

Zettle 1989

MethodsDesign: RCT of parallel design
Study duration: 12 weeks
Follow-up: 2 months after end of therapy


ParticipantsSample size: 45 individuals eligible for the study, of whom 37 agreed to participate      

Recruitment: media advertisements

Inclusion criteria—diagnostic classification criteria: not reported

Inclusion criteria—rating scales: BDI score ≥ 20, MMPI Depression Scale T score ≥ 70/score greater than T scores on psychasthenia and hysteria scales, HRSD score ≥ 14

Included disorders: moderate to severe depression

Gender: female participants only

Mean age: 41.3 years

Country/Ethnicity: conducted in USA; no information on ethnicity of participants provided

Pharmacotherapy during the study: before treatment began, participants required to verify that they were not taking antidepressants or tranquilising medications


InterventionsComplete cognitive therapy package (CCT)

Intervention: CCT used full complement of therapeutic procedures and strategies common to CT, including distancing, cognitive restructuring and behavioural hypothesis testing. Distancing procedures included use of similes, reattribution techniques and alternative conceptualisations. Therapy conducted in groups of 4 to 7 participants, who met for 12 weekly sessions of 90 min each

Therapists: CCT provided by first author, who had received previous training in CT and CD, assisted by second author, a graduate student. Supervision arrangements not reported

Partial cognitive therapy package (PCT)

Intervention: condition differed from CCT in the absence of any distancing procedures. Therapy conducted in groups of 4 to 7 participants, who met for 12 weekly sessions of 90 min each

Therapists: CCT provided by first author, who had received previous training in CT and CD, assisted by second author, a graduate student. Supervision arrangements not reported

Comprehensive distancing (CD)

Intervention: condition derived from a behavioural view of cognitive activity (Hayes 1987), based on three key themes that efforts to change depressive thoughts evoke the very thoughts to be eliminated, that depressive thoughts put forward as reasons for dysfunctional actions are merely more behaviour and that treating depressive thoughts as behaviour in context makes it possible to behave more effectively despite the continued presence of negative thinking. Therapy conducted in groups of 4 to 7 participants, who met for 12 weekly 90-min sessions

Therapists: CCT provided by first author, who had received previous training in CT and CD, assisted by second author, a graduate student. Supervision arrangements not reported


OutcomesBDI

HRSD

Automatic Thoughts Questionnaire

Dysfunctional Attitude Scale      

Pleasant Events Schedule (Activity Level, Reinforcement Potential and Obtained Reinforcement)


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskNo information provided

Allocation concealment (selection bias)Unclear riskNo information provided

Blinding of participants and personnel (performance bias)
All outcomes
High riskNot possible to blind participants and clinicians in a psychological therapy trial

Blinding of outcome assessment for observer-rated scales (detection bias)Low riskEvaluator blind to each participant treatment condition and completed the HRSD after both interviews (page 438, para 4)

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskDropout rate of 16% and no reasons provided for attrition. No statistical methods used for taking account of missing data—dropouts excluded from further analysis (page 438, para 2)

Selective reporting (reporting bias)Unclear riskNo study protocol available—insufficient information to allow an assessment

Primary efficacy outcome not specified a priori, in terms of what aspect of efficacy would be measured or which measure

Researcher allegiance and other conflicts of interest (financial or other)High riskCitation in Background section indicates that first author had conducted previous comprehensive distancing trial with Dr Steve Hayes, who developed and manualised ACT

Therapist allegiance and other conflicts of interest (financial or other)Unclear riskFirst author was primary therapist, assisted by coauthor. Therapist allegiance to comprehensive distancing indicated in Background. However, questionnaire adapted from Rose 1984 was administered at end of each treatment session to assess the presence of any potential bias or other nonspecific effects that might favour one condition over another. Significant difference between groups noted for session 5 only when PCT participants reported a more favourable evaluation than the other two groups (page 440, para 3)

Therapist qualificationsUnclear riskPrimary therapist had received previous training in CT and comprehensive distancing. Assisted by graduate student (page 439, para 2)

Treatment fidelityUnclear riskAudiotapes of sessions reviewed by two judges familiar with treatment manuals but blind to each group's treatment condition (page 440, para 2)—able to classify 21 out of 24 tapes correctly. No use of fidelity scales

Other biasUnclear riskInsufficient information provided

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Armento 2011Comparator was a control condition—study included in third wave CBT vs TAU review

Azargoon 2010Comparator was a control condition—study included in third wave CBT vs TAU review

Ekers 2011Comparator was a control condition—study included in third wave CBT vs TAU review

Ekkers 2011Comparator was a control condition—study included in third wave CBT vs TAU review

Folke 2012Did not meet diagnostic inclusion criteria—sample had long-term depression

Gawrysiak 2009Comparator was a control condition—study included in third wave CBT vs TAU review

Kaviani 2012Did not meet diagnostic inclusion criteria—sample had subclinical depression

Korrelboom 2012Did not meet diagnostic inclusion criteria—sample in partial remission

Manicavasgar 2011Three of eleven treatment groups not randomly allocated

Pellowe 2007Comparator was a control condition—study included in third wave CBT vs TAU review

Pinniger 2012Did not meet diagnostic inclusion criteria—mixed population

 
Characteristics of ongoing studies [ordered by study ID]
NCT01070134

Trial name or title'Third wave' cognitive therapy versus psychodynamic therapy (PD) for patients with major depressive disorder in psychotherapeutic day treatment: a randomised clinical pilot trial

MethodsRandomised controlled trial

ParticipantsAdults diagnosed with major depressive disorder, referred to the day clinic, Roskilde Psychiatric Services

Interventions
  • Mindfulness-based behavioural therapy—weekly individual MIBT (45 to 50 minutes), together with weekly mindfulness skills training group (1.5 hours) for 18 weeks
  • Mentalisation-based therapy—weekly individual PT therapy (45 to 50 minutes), together with weekly PT group therapy (1.5 hours) for 18 weeks

OutcomesPrimary outcome: HAD-D

Secondary outcomes: SCL-90-R, proportion of participants who achieve remission (HAM-D score < 8)

Starting dateFebruary 2010

Contact informationJanus Jakobsen janusjakobsen@mac.com

NotesEstimated study completion date: August 2011

NCT01517503

Trial name or titleAcceptance and commitment therapy versus cognitive therapy for the treatment of major depressive disorder

MethodsRandomised controlled trial

ParticipantsAdults with major depressive disorder in routine clinical practice

Interventions
  • Cognitive therapy: maximum of 20 45-minute sessions to be provided over 16 weeks, with sessions held twice weekly for the first 6 weeks and once weekly for the next 8 weeks
  • Acceptance and commitment therapy: maximum of 20 45-minute sessions to be provided over 16 weeks, with sessions held twice weekly for the first 6 weeks and once weekly for the next 8 weeks

OutcomesPrimary outcomes: Quick Inventory of Depressive Symptomatology, HAM-D

Secondary outcomes: Decentering Subscale of Experiences Questionnaire, Acceptance and Action Questionnaire, Dysfunctional Attitude Scale-Revised, Working Alliance Inventory, Europhis Quality of Life Scale, Relationship Scales, Implicit Attitude Test, Structured Clinical Inverview for DSM-IV

Starting dateDecember 2011

Contact informationNexhmedin Morina: n.morina@uva.nl

NotesEstimated study completion date: December 2014

 
Comparison 1. Third wave CBT vs other psychological therapies

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Clinical response at post-treatment3144Risk Ratio (M-H, Random, 95% CI)1.14 [0.79, 1.64]

    1.1 ACT vs other psychological therapies
256Risk Ratio (M-H, Random, 95% CI)1.11 [0.60, 2.04]

    1.2 Extended BA vs other psychological therapies
188Risk Ratio (M-H, Random, 95% CI)1.16 [0.73, 1.83]

 2 Clinical response at follow-up2Risk Ratio (M-H, Random, 95% CI)Subtotals only

    2.1 ACT vs other psychological therapies
256Risk Ratio (M-H, Random, 95% CI)0.31 [0.08, 1.26]

 3 Treatment acceptability (dropout) at post-treatment3144Risk Ratio (M-H, Random, 95% CI)1.12 [0.47, 2.67]

    3.1 ACT vs other psychological therapies
256Risk Ratio (M-H, Random, 95% CI)1.07 [0.10, 11.23]

    3.2 Extended BA vs other psychological therapies
188Risk Ratio (M-H, Random, 95% CI)1.22 [0.45, 3.34]

 4 Treatment acceptability (dropout) at follow-up2Risk Ratio (M-H, Random, 95% CI)Subtotals only

    4.1 ACT vs other psychological therapies
256Risk Ratio (M-H, Random, 95% CI)1.07 [0.10, 11.23]

 5 Remission at post-treatment1Risk Ratio (M-H, Random, 95% CI)Totals not selected

 6 Depression levels at post-treatment3113Mean Difference (IV, Random, 95% CI)-1.65 [-4.17, 0.88]

    6.1 ACT vs other psychological therapies
250Mean Difference (IV, Random, 95% CI)-2.58 [-6.39, 1.24]

    6.2 Extended BA vs other psychological therapies
163Mean Difference (IV, Random, 95% CI)-0.93 [-4.35, 2.50]

 7 Depression levels at follow-up249Mean Difference (IV, Random, 95% CI)-4.51 [-7.47, -1.55]

    7.1 ACT vs other psychological therapies
249Mean Difference (IV, Random, 95% CI)-4.51 [-7.47, -1.55]

 
Summary of findings for the main comparison. Mindfulness-based 'third wave' cognitive and behavioural therapies compared with other psychological therapies for depression

Mindfulness-based 'third wave' cognitive and behavioural therapies compared with other psychological therapies for depression

Patient or population: individuals with depression
Settings: primary, secondary and community care
Intervention: mindfulness-based 'third wave' cognitive and behavioural therapies
Comparison: other psychological therapies

OutcomesIllustrative comparative risks* (95% CI)Relative effect
(95% CI)
No of participants
(studies)
Quality of the evidence
(GRADE)
Comments

Assumed riskCorresponding risk

Other psychological therapiesMindfulness-based 'third wave' cognitive and behavioural therapies

Clinical non-response at post-treatmentStudy populationRR 1.14
(0.79 to 1.64)
144
(3 studies)
⊕⊝⊝⊝
very lowa,b,c

427 per 1000487 per 1000
(337 to 700)

Moderate

422 per 1000481 per 1000
(333 to 692)

Clinical non-response at follow-up: ACT vs other psychological therapies
Follow-up: 2 months
Study populationRR 0.31
(0.08 to 1.26)
56
(2 studies)
⊕⊝⊝⊝
very lowa,b,c

351 per 1000109 per 1000
(28 to 443)

Moderate

347 per 1000108 per 1000
(28 to 437)

Treatment acceptability at post-treatment
Dropout rates
Study populationRR 1.12
(0.47 to 2.67)
144
(3 studies)
⊕⊝⊝⊝
very lowa,b,c

134 per 1000150 per 1000
(63 to 358)

Moderate

133 per 1000149 per 1000
(63 to 355)

Treatment acceptability at follow-up: ACT versus other psychological therapies
Dropout rates
Follow-up: 2 months
Study populationRR 1.07
(0.1 to 11.23)
56
(2 studies)
⊕⊝⊝⊝
very lowa,c,d,e

135 per 1000145 per 1000
(14 to 1000)

Moderate

100 per 1000107 per 1000
(10 to 1000)

Non-remission at post-treatmentStudy populationRR 0.89
(0.6 to 1.3)
88
(1 study)
⊕⊝⊝⊝
very lowe,f,g

578 per 1000514 per 1000
(347 to 751)

Moderate

578 per 1000514 per 1000
(347 to 751)

Depression levels at post-treatment

(HAM-D)
Mean depression levels at post-treatment in the intervention groups was
1.65 lower
(4.17 lower to 0.88 higher)
113
(3 studies)
⊕⊝⊝⊝
very lowa,b,c

Depression levels at follow-up: ACT vs other psychological therapies

(HAM-D)
Follow-up: 2 months
Mean depression levels at follow-up of ACT vs other psychological therapies in the intervention groups were
4.51 lower
(7.47 to 1.55 lower)
49
(2 studies)
⊕⊝⊝⊝
very lowa,c,e

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the risk ratio of the intervention (and its 95% CI).
CI: Confidence interval; RR: Risk ratio.

GRADE Working Group grades of evidence.
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

 aThe method of sequence generation/allocation concealment was unclear in two studies. As with all psychological therapy trials, blinding of clinicians/participants was not achievable. The risk of bias was assessed as high for researcher allegiance and as unclear for treatment fidelity and therapist qualifications.
bOnly two third wave approaches were included and/or the comparator psychological therapy approaches were limited to CBT.
cSample sizes were small and/or confidence intervals were wide.
dModerate statistical heterogeneity was indicated.
eCompared against only one other psychological therapy approach.
fAs with all psychological therapy trials, blinding of clinicians/participants was not achievable. The risk of bias was assessed as high for researcher allegiance and as unclear for treatment fidelity and therapist qualifications.
gOnly one study provided clinical remission data.