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'Third wave' cognitive and behavioural therapies versus treatment as usual for depression

  1. Rachel Churchill1,*,
  2. Theresa HM Moore2,
  3. Toshi A Furukawa3,
  4. Deborah M Caldwell2,
  5. Philippa Davies2,
  6. Hannah Jones4,
  7. Kiyomi Shinohara5,
  8. Hissei Imai6,
  9. Glyn Lewis7,
  10. Vivien Hunot1

Editorial Group: Cochrane Common Mental Disorders Group

Published Online: 18 OCT 2013

Assessed as up-to-date: 1 FEB 2013

DOI: 10.1002/14651858.CD008705.pub2


How to Cite

Churchill R, Moore THM, Furukawa TA, Caldwell DM, Davies P, Jones H, Shinohara K, Imai H, Lewis G, Hunot V. 'Third wave' cognitive and behavioural therapies versus treatment as usual for depression. Cochrane Database of Systematic Reviews 2013, Issue 10. Art. No.: CD008705. DOI: 10.1002/14651858.CD008705.pub2.

Author Information

  1. 1

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

    Kyoto University Graduate School of Medicine / School of Public Health, Department of Field Medicine, Kyoto, Japan

  7. 7

    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, 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]
Ekers 2011

MethodsDesign: RCT, parallel design, multi-centre

Study duration: 3 months

Follow-up: none


ParticipantsSample size: 47 individuals eligible and agreed to participate    

Recruitment: referred by GPs (n = 26) or mental health workers (n = 21) in participating general practices

Inclusion criteriadiagnostic classification criteria: ICD-10 diagnosis made using computerised version of CISR

Inclusion criteriarating scales: none

Included disorders: depression

Gender: 62% of sample women

Mean age: 44.7 years (range 24 to 63 years)

Country/Ethnicity: conducted in UK: no information on ethnicity

Pharmacotherapy during the study: naturalistic prescribing of antidepressants to 68% of participants (65% in BA arm and 71% in UC arm)


InterventionsBehavioural activation (BA)

Intervention:  BA consisted of a structured programme of increasing contact with potentially antidepressant environmental reinforcers through scheduling and reducing the frequency of negatively reinforced avoidance behaviours. Specific techniques incorporated in the 12-session protocol were self-monitoring, identifying 'depressed behaviours', developing alternative goal-orientated behaviours and scheduling. In addition, the role of avoidance and rumination was addressed through functional analysis, and alternative responses developed. Participants received twelve 1-hour individual face-to-face sessions over a 3-month period

Therapists:  BA was provided by two qualified mental health nurses with no previous formal psychotherapeutic training or experience. Both had worked in a range of services in inpatient and community settings with 3 and 6 years' experience since qualification. Therapists received 5 days of training in BA and 1 hour of clinical supervision fortnightly from the PI

Usual care (UC)

Participants were followed up by their GP or primary care mental health worker and were offered interventions deemed appropriate for their condition as per normal practice


OutcomesBDI-II

Work and Social Adjustment Scale (WSAS)

Client Satisfaction Questionnaire (CSQ-8)


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskNot described

Allocation concealment (selection bias)Unclear riskParticipants randomly assigned to two arms through an allocation concealment process independent of the study team (page 67, col 1, para 2)—no further information provided

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

Blinding of outcome assessment (detection bias)
All outcomes
High riskAll outcomes self-report—not possible to blind participants in a psychological therapy trial

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskAppropriate statistical methods used to take account of missing data; however, differential dropout rates between the two arms (16% in BA arm vs 5% in UC arm) and no reasons for dropout provided

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

Researcher allegiance and other conflicts of interest (financial or other)High risk12-Session protocol followed for sessions (treatment manual available from author—page 67, col 1, para 5) based on two behavioural approaches developed in previous research (Martell 2001 and Hopko 2003a)

Therapist allegiance and other conflicts of interest (financial or other)Low riskNo previous training in psychotherapy for therapists

Therapist qualificationsHigh riskNo previous therapy training for therapists; relatively recently qualified, employed at the base level of registered psychiatric nurses (page 71, col 1, para 5) with only 5 days of training in BA

Treatment fidelityLow riskAll treatment sessions audiotaped and 20% randomly selected by a research assistant masked to session content. Recordings assessed by independent accredited CBT therapists with extensive experience in both CBT and BA (page 67, col 2, para 3). All sessions classed 1 as an example of BA and 0 when other therapy modes were prominent (page 69, col 1, para 2)

Other biasUnclear riskInsufficient information provided

Ekkers 2011

MethodsDesign: RCT, parallel design, single centre

Study duration: 7 weeks

Follow-up: none


ParticipantsSample size: 93 individuals eligible and agreed to participate    

Recruitment: referred by therapists working in four older age outpatient departments of psychiatric institute

Inclusion criteriadiagnostic classification criteria: clinically established diagnosis of MDD based on DSM-IV-TR criteria, obtained through multidisciplinary team meeting between psychiatrist, clinical psychologist and nurse

Inclusion criteriarating scales: 11 or more on Geriatric Depression Scale

Included disorders: major depressive disorder

Gender: 67% of sample women

Mean age: 72.7 years

Country/Ethnicity: conducted in Netherlands: no information on ethnicity

Pharmacotherapy during the study: naturalistic prescribing of antidepressants to 79% of participants (75% in COMET arm and 83% in treatment as usual arm)


InterventionsCompetitive Memory Training (COMET)

Intervention:  COMET for depressive rumination targets underlying cognitive processes instead of the content of dysfunctional cognitions. Its aim is not to change the negative emotions and thoughts themselves but rather the amount of involvement the individual has with these thoughts and emotions. Using counter themes of being indifferent or adopting an attitude of acceptance, clients are trained to become more emotionally salient. COMET conducted in groups of 6 to 8 participants in 7 manualised sessions of 90 minutes each. Participants also received ongoing treatment as usual (see description below)

Therapists:  all sessions administered by two trained therapists. At least one of the therapists was a registered cognitive-behavioural therapist. All therapists trained and supervised by the first two authors. Training consisted of 8 hours' training in the theory and practice of the COMET protocol. All therapists met once a month for 1 hour with the first author to discuss progress/deal with treatment issues

Treatment as usual (TAU)

Consisted mainly of pharmacotherapy prescribed by a psychiatrist, with or without psychotherapy conducted by a psychologist, or supportive and structured treatment conducted by nurses who specialised in psychosocial and psychiatric care


OutcomesQuick Inventory of Depressive Symptomatology–Self Report (QIDS-SR)

Geriatric Depression Scale (GDS)

Ruminative Response Scale (RRS)

Rumination on Sadness Scale (RSS)


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskTherapists at each of the four locations received 38 closed envelopes containing an equal number of allocations to both conditions (page 591, col 1, para 1). No information on how envelopes were selected

Allocation concealment (selection bias)Low riskPreparation of envelopes and randomisation procedures carried out by independent assistants with no involvement at all of the researchers (page 591, col 1, para 1)

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

Blinding of outcome assessment (detection bias)
All outcomes
High riskOutcomes all self-report—not possible to blind participants in a psychological therapy trial

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskAppropriate statistical methods used to take account of missing data; however, very high dropout rate of 50% in TAU arm, incomplete figures provided on reasons for dropout and authors report that some people in TAU arm were disappointed not to be randomly assigned into the COMET group (page 592, col 1, para 1)

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

Researcher allegiance and other conflicts of interest (financial or other)High riskSecond author developed the COMET intervention (page 589, col 1, para 2)

Therapist allegiance and other conflicts of interest (financial or other)Unclear riskGroup sessions of COMET administered by two trained therapists; at least one of the therapists was a registered cognitive-behavioural therapist (page 590, col 1, para 4); however, authors do not state in which approach remaining therapists had been trained

Therapist qualificationsUnclear riskNo information provided on therapist qualifications or experience, except that some were registered cognitive-behavioural therapists. Eight hours' training in theory and practice of COMET provided (page 590, col 1, para 4)

Treatment fidelityUnclear riskSample of the COMET sessions observed by an independent rater, who assessed deliverance of the manualised steps for each session by ticking a list of treatment elements and elements not included in the manual (page 591, col 1, para 1). 90% of elements of the protocol delivered (page 592, col 2, para 3). However, no information provided on method used for observing sessions, number of sessions assessed or status of raters

Other biasUnclear riskInsufficient information provided

Gawrysiak 2009

MethodsDesign: RCT, parallel design, single centre

Study duration: 2 weeks

Follow-up: none


ParticipantsSample size: 30 individuals eligible and agreed to participate    

Recruitment: volunteer psychology students based at a public university

Inclusion criteriadiagnostic classification criteria: none

Inclusion criteriarating scales: score of 14 or higher on BDI-II

Included disorders: depression

Gender: 80% of sample women

Mean age: 18.4 years (SD 0.81)

Country/Ethnicity: conducted in USA: 70% Caucasian, 13% African American, 7% Latino, 7% Asian American, 3% other

Pharmacotherapy during the study: participants required not to be receiving pharmacological treatment


InterventionsBehavioural Activation Treatment for Depression (BATD)

Intervention:  based on premise that increased activity and resulting experience of environmental reinforcement are sufficient for reduction of depressive symptoms/corresponding increase in positive thoughts and feelings. Emphasis on engaging in value-based activities that elicit a sense of pleasure and accomplishment. Treatment protocol for current study represented major modification to original BATD intervention in that it was reduced to a single session. Treatment consisted of a single individual 90-minute face-to-face session

Therapists:  Two male doctoral students in clinical psychology who were trained in BATD administered the intervention. No other information provided on training, qualifications, experience and supervision

No treatment control

Control group participants completed questionnaires, were provided with a brief explanation of the study and were told to engage in their lives as usual


OutcomesBDI-II

Environmental Reward Observation Scale (EROS)

Beck Anxiety Inventory (BAI)

Multidimensional Scale of Perceived Social Support (MSPSS)


NotesPotential participants were offered credit for taking part in the study


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskNot described

Allocation concealment (selection bias)Unclear riskNot described

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

Blinding of outcome assessment (detection bias)
All outcomes
High riskAll outcomes self-report—not possible to blind participants in a psychological therapy trial

Incomplete outcome data (attrition bias)
All outcomes
Low risk0% attrition in both BATD and control conditions at 2-week follow-up (page 471, col 2, para 3)

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

Researcher allegiance and other conflicts of interest (financial or other)High riskLast author, DR Hopko, developed BATD and this modified version of BATD and is the contact author for the study 

Therapist allegiance and other conflicts of interest (financial or other)Unclear riskNo information provided on therapists' previous training or preferred psychological therapy approach

Therapist qualificationsUnclear riskTherapists were non-qualified doctoral students in clinical psychology (page 471, col 1, para 5). No information provided on their level of experience. No information provided on training in BATD and supervision

Treatment fidelityHigh riskTreatment fidelity measured by therapists' checking off/initialing a list of therapy components in treatment protocol (page 471, col 1, para 3). No audiotaping/videotaping, no independent assessments; therefore no evidence that treatment was delivered as specified

Other biasUnclear riskInsufficient information provided

Pellowe 2006

MethodsDesign: RCT, parallel design, single centre

Study duration: 4 weeks

Follow-up: none


ParticipantsSample size: 54 individuals eligible and agreed to participate    

Recruitment: volunteer psychology students

Inclusion criteriadiagnostic classification criteria: none

Inclusion criteriarating scales: score of 10 to 29 on BDI-II

Included disorders: mild to moderate depression

Gender: 70% of sample women

Mean age: 20.4 years (SD 4.73)

Country/Ethnicity: conducted in USA: 92% of participants Caucasian, 6% Hispanic and 3% African American

Pharmacotherapy during the study: naturalistic prescribing allowed—4 participants in ACT group and no participants in supportive therapy group taking medication for a psychological condition


InterventionsAcceptance and commitment therapy (ACT)

Intervention:  Session 1 focused on a discussion of value-directed living and typical means of coping with private events associated with depression. Session 2 covered ineffective use of control strategies and introduction to cognitive defusing. Session 3 introduced the concept of mindfulness. Session 4 reviewed core concepts of ACT and discussed how to maintain valued life direction

Therapists:  groups led by 1 or 2 advanced clinical psychology graduate students trained in the respective therapy protocols. Author facilitated most sessions

Supportive group therapy (SGT)

Intervention: SGT was intended to provide a clinically relevant comparison treatment for ACT but was regarded as a placebo control condition, consisting of relatively unstructured group discussion prompted by facilitators, with avoidance of CBT and ACT techniques

Therapists: groups led by one or two advanced clinical psychology graduate students trained in the respective therapy protocols. Author facilitated most sessions


OutcomesAcceptance and Action Questionnaire (ACT)

BDI-II

Dysfunctional Attitude Scale (DAS)

Final Session Questionnaire (satisfaction scale)


NotesSGT categorised as psychological placebo as participants are likely to have believed that they were receiving an active treatment, although the author regarded it as a placebo control


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskNot described

Allocation concealment (selection bias)Unclear riskNot described

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

Blinding of outcome assessment (detection bias)
All outcomes
High riskAll outcomes self-report—not possible to blind participants in a psychological therapy trial

Incomplete outcome data (attrition bias)
All outcomes
Low riskDropout very low in both groups (2 in ACT group) and reasons for dropout provided (page 43, para 2). Appropriate statistical methods used to take account of missing data

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

Researcher allegiance and other conflicts of interest (financial or other)High riskResearcher states that 'the current study ulitized an attention control group rather than an active treatment such as CBT' (page 34, para 1), indicating an allegiance towards ACT

Therapist allegiance and other conflicts of interest (financial or other)High riskResearcher facilitated most sessions in both treatment conditions (page 41, para 1)

Therapist qualificationsUnclear riskTwo advanced clinical psychology graduate students trained in respective therapy protocols. No information provided on level of experience (page 41, para 1)

Treatment fidelityLow riskAll sessions videotaped and random selection of 15 tapes reviewed by a trained independent judge, who was familiar with manuals but blind to condition (page 41, para 1). Judge used checklist for 8 ACT sessions reviewed—all exercises included (page 41, para 2)

Other biasUnclear riskInsufficient information provided

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Bohlmeijer 2011A defined depression scale cut-off not applied by researchers

Dimidjian 2004Comparator condition of active treatment

Folke 2012Not an acute depression population—participants with chronic depression (mean of 351 days' consecutive sick leave)

Hopko 2003aInpatient population

Kaviani 2012Not an acute depression population—participants with subclinical depression

Korrelboom 2012Participants already in treatment for depression; high proportion of sample in partial remission

Pinniger 2012Mixed population with self-reported stress, anxiety and/or depression; no defined depression scale cut-off

Reynolds 2011Participants' mean depression score in the normal range

Snarski 2011Inpatient participants who had mild to moderate cognitive impairment

Zettle 1984Comparator condition of active treatment

Zettle 1989Comparator condition of active treatment

 
Characteristics of studies awaiting assessment [ordered by study ID]
Armento 2012

MethodsRandomised controlled trial

ParticipantsMild to moderately depressed undergraduate students

Interventions
  • Religious action in behavioural activation (PRA-BA): individualised one-session intervention of 60 minutes, followed by 2-week activation interval
  • No treatment 'support' condition: individualised one-session intervention of 60 minutes, providing a supportive environment, followed by 2-week interval of life as usual

OutcomesBDI-II

Environmental Reward Observation Scale

State-Trait Anxiety Inventory

BAI

Quality of Life Inventory

Religious Background and Behaviour Scale

Spiritual Well-being Scale

Ways of Religious Coping Scale

NotesTrial used the same one-session extended BA protocol as Gawrysiak 2009, revised to focus on religious behaviours

Azargoon 2010

MethodsRandomised controlled trial

ParticipantsDepressed students

InterventionsMindfulness training versus no treatment control. Mindfulness training consisting of 8 weekly two-hour sessions

OutcomesDAS Inventory and ATQ Questionnaire

NotesPaper written in Farsi—translation required

 
Characteristics of ongoing studies [ordered by study ID]
NCT01441258

Trial name or titleAdaptation of Dialectical Behavior Therapy Skills-Groups for Individuals With Suicidal Ideation and Depression

MethodsRandomised controlled trial

ParticipantsAdult participants with MDD who also report current suicidal ideation

Interventions
  • Dialectical behaviour therapy skills (DBT-S): weekly group DBT-S (1.5-hour sessions) in groups of 8 participants, for 18 weeks
  • Waiting list: participants to be seen by their standard treaters for 18 weeks as usual and given the opportunity to participate in a DBT skills group after 18-week wait period has ended

OutcomesPrimary outcome: Beck Scale for Suicidal Ideation

Starting dateOctober 2011

Contact informationKate A Hails: khails@partners.org

NotesEstimated completion date—May 2013

 
Comparison 1. Third wave CBT versus TAU

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

 1 Clinical response at post-treatment3170Risk Ratio (M-H, Random, 95% CI)0.51 [0.27, 0.95]

    1.1 Behavioural activation vs TAU
277Risk Ratio (M-H, Random, 95% CI)0.29 [0.05, 1.56]

    1.2 Others (COMET) vs TAU
193Risk Ratio (M-H, Random, 95% CI)0.65 [0.52, 0.83]

 2 Treatment acceptability (dropout) at post-treatment4224Risk Ratio (M-H, Random, 95% CI)1.01 [0.08, 12.30]

    2.1 Behavioural activation vs TAU
277Risk Ratio (M-H, Random, 95% CI)3.65 [0.85, 15.78]

    2.2 ACT vs TAU
154Risk Ratio (M-H, Random, 95% CI)3.0 [0.13, 70.53]

    2.3 Others (COMET) vs TAU
193Risk Ratio (M-H, Random, 95% CI)0.15 [0.06, 0.41]

 3 Clinical remission at post-treatment2140Risk Ratio (M-H, Random, 95% CI)0.77 [0.67, 0.88]

    3.1 Behavioural activation vs TAU
147Risk Ratio (M-H, Random, 95% CI)0.70 [0.48, 1.00]

    3.2 Others (COMET) vs TAU
193Risk Ratio (M-H, Random, 95% CI)0.78 [0.67, 0.90]

 4 Depression levels at post-treatment4211Std. Mean Difference (IV, Random, 95% CI)-1.12 [-1.53, -0.71]

    4.1 Behavioural activation vs TAU
268Std. Mean Difference (IV, Random, 95% CI)-1.36 [-1.90, -0.82]

    4.2 ACT vs TAU
152Std. Mean Difference (IV, Random, 95% CI)-0.60 [-1.16, -0.04]

    4.3 Others (COMET) vs TAU
191Std. Mean Difference (IV, Random, 95% CI)-1.27 [-1.73, -0.82]

 5 Anxiety levels at post-treatment1Mean Difference (IV, Random, 95% CI)Totals not selected

    5.1 Behavioural activation vs TAU
1Mean Difference (IV, Random, 95% CI)0.0 [0.0, 0.0]

 6 Social adjustment levels at post-treatment1Mean Difference (IV, Random, 95% CI)Totals not selected

    6.1 Behavioural activation vs TAU
1Mean Difference (IV, Random, 95% CI)0.0 [0.0, 0.0]

 
Comparison 2. Third wave CBT vs types of control condition

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

 1 Clinical response at post-treatment3Risk Ratio (M-H, Random, 95% CI)Subtotals only

    1.1 Third wave CBT vs TAU/usual care/no treatment
3170Risk Ratio (M-H, Random, 95% CI)0.51 [0.27, 0.95]

 2 Treatment acceptability (dropout) at post-treatment4224Risk Ratio (M-H, Random, 95% CI)1.01 [0.08, 12.30]

    2.1 Third wave CBT vs TAU/usual care/no treatment
3170Risk Ratio (M-H, Random, 95% CI)0.71 [0.03, 16.07]

    2.2 Third wave CBT vs psychological placebo
154Risk Ratio (M-H, Random, 95% CI)3.0 [0.13, 70.53]

 
Summary of findings for the main comparison. Third wave CBT versus TAU for depression

Third wave CBT versus TAU for depression

Patient or population: depression
Settings: primary, secondary and community care
Intervention: third wave CBT

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

Assumed riskCorresponding risk

ControlThird wave CBT

Clinical non-response at post-treatmentStudy populationRR 0.51
(0.27 to 0.95)
170
(3 studies)
⊕⊝⊝⊝
very lowa,b,c

800 per 1000408 per 1000
(216 to 760)

Moderate

688 per 1000351 per 1000
(186 to 654)

Treatment acceptability (dropout) at post-treatmentStudy populationRR 1.01
(0.08 to 12.3)
224
(4 studies)
⊕⊝⊝⊝
very lowa,b,d,e,f

206 per 1000208 per 1000
(16 to 1000)

Moderate

42 per 100042 per 1000
(3 to 517)

Clinical non-remission at post-treatmentStudy populationRR 0.77
(0.67 to 0.88)
140
(2 studies)
⊕⊝⊝⊝
very lowa,c,d,f

953 per 1000734 per 1000
(639 to 839)

Moderate

938 per 1000722 per 1000
(628 to 825)

Depression levels at post-treatmentMean depression levels at post-treatment in the intervention groups were
1.12 standard deviations lower
(1.53 to 0.71 lower)
211
(4 studies)
⊕⊝⊝⊝
very lowa,d,f,g
SMD -1.12 (-1.53 to -0.71)

Anxiety levels at post-treatment—behavioural activation vs TAU

Beck Anxiety Inventory (BAI)
Mean anxiety levels at post-treatment—behavioural activation vs tau in the intervention groups was
5.5 lower
(10.01 to 0.99 lower)
30
(1 study)
⊕⊝⊝⊝
very lowa,f,h

Social adjustment levels at post-treatment— behavioural activation vs TAU

Work and Social Ajustment Scale (WSAS)
Mean social adjustment levels at post-treatment—behavioural activation vs tau in the intervention groups was
11.56 lower
(17.89 to 5.23 lower)
38
(1 study)
⊕⊝⊝⊝
very lowa,b,d,f

*The basis for the assumed risk (eg, 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.

 aMethod of sequence generation/allocation concealment unclear. 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 therapist qualifications.
bSubstantial statistical heterogeneity indicated. Diverse study settings and participants (use of student population vs older age population). Treatment length varied from a single session to 12 sessions over 3 months.
cOnly two third wave CBT approaches included.
dHigh proportion of participants prescribed antidepressants naturalistically.
eOne study used a single-session intervention; therefore no dropouts from treatment. One study had 50% dropout rate in TAU group vs 8% in third wave CBT group.
fSmall to very small sample sizes with wide confidence intervals.
gModerate statistical heterogeneity indicated. Treatment length varied from a single session to 12 sessions over 3 months.
hOne study limited to single-session intervention with college students reporting mild depression.