Table 4 Between-group comparisons in outcomes clustered by research design

[35] (2011)

RCT

[Excellent]

Motivational Enhancement Treatment (MET) + PT: (n = 38) included proxy efficacy, treatment expectancy, therapeutic alliance, and empathy, combined with physical therapy

PT (n = 38): 30-min physical therapy (PT) sessions for 8 weeks, including 15 min of interferential therapy and a tailored back exercise programme. Dummy MET included general communication (non-counselling) skills

MET + PT

Post: M = 3.3 (± 2.1)

1-month: M = 3.1 (± 2.1)

PT only:

Post: M = 3.6 (± 2.4)

1-month: M = 3.9 (± 2.5)

MET + PT ~ PT

(p = .50)

95% C.I. [− 1.09 to 0.54]

MET + PT larger reduction in pain intensity than PT-alone but non-significant

MET + PT

Post: M = 6.3 (± 4.8)

1-month: M = 5.6 (± 4.5)

PT only

M = 7.2 (± 5.6)

1-month: M = 7.6 (± 6.4)

MET + PT ~ PT

(p = .424)

95% C.I. [− 2.83 to 1.44]

MET + PT larger reduction in physical disability than PT-alone but non-significant

[36] (2013)

RCT

[Excellent]

Cognitive Functional Therapy (CFT) (n = 51): focuses on reframing back pain in a person-centred manner along with altering maladaptive/unhelpful behaviours to normalise movement

MT-EX (n = 43): consisted of manual therapy and exercise which included joint mobilisation or manipulation applied to the spine or pelvis; most patients (82.5%) were given exercises or a home exercise programme

CFT

Post: M = 1.7 (± 1.7)

1-year: M = 2.3 (± 2.0)

MT-EX

Post: M = 3.8 (± 1.9)

1-year: M = 3.8 (± 2.1)

CFT > MT-EX

Post: (p < .001)

M_Diff = − 2.1

95% C.I. [− 2.7 to − 1.4]

1-year: (p < .001)

M_Diff = − 1.3

95% C.I. [− 2.1 to − 0.5]

Effect size unreported

CFT

Post: M = 7.6 (± 6.7)

1-year: M = 9.9 (± 9.8)

MT-EX

Post: M = 18.5 (± 8.1)

1-year:M = 19.7 (± 11.7)

CFT > MT-EX

Post: (p < .001)

M_Diff = − 9.7

95% C.I. [− 12.7 to − 6.7]

1-year: (p < .001)

M_Diff = − 8.2

95% C.I. [− 12.6 to − 3.8]

Effect size unreported

[37] (2014)

RCT (2 × 2)

[Excellent]

Enhanced versus limited therapeutic alliance (TA) following active or sham interferential current therapy (IFC)

Variation of CFs:

Enhanced TA ( E ):

AE: Active IFC (n = 29)

SE: Sham IFC (n = 29)

Limited TA ( L ):

AL: Active IFC (n = 30)

SL: Sham IFC (n = 29)

Significant differences between the SL and the AL, AE & SE groups

Compared to SL (Sham IFC/Limited TA) mean differences were:

AE: MΔ = 2.3

SE: MΔ = 1.19

AL: MΔ = 0.8

( p  < .01)

Dose response

AE > SL: d = 2.51

Enhanced > Limited TA

SE > SL: d = 1.73

AE > AL: d = 1.36

Active > Sham IFC

AE > SE: d = 1.0

AL > SL: d = 0.89

Not applicable

Not applicable

[38] (2022)

RCT

[Excellent]

PRT (n = 50): Pain Reprocessing Therapy (PRT) aims to shift patients’ beliefs about the causes and threat value of pain

TAU (n = 50): Treatment as usual; Participants were given no additional treatment and agreed to continue their ongoing care as usual and not start new treatments before the post-treatment assessment

PRT

Post: M = 1.18 (± 1.24)

1-year: M = 1.51 (± 1.59)

TAU

Post: M = 3.13 (± 1.45)

1-year: M = 3.0 (± 1.77)

PRT > TAU

Post: (p < .001)

g (SE) =  − 1.75 (0.24)

1-year: (p < .001)

g (SE) =  − 1.05 (0.24)

PRT

Post: M = 10.14 (± 10.6)

1-year: M = 11.16 (± 13.1)

TAU

Post: M = 20.68 (± 10.7)

1-year: M = 18.78 (± 12.6)

PRT > TAU

Post: (p < .001)

g (SE) =  − 1.70 (0.26)

1-year: (p < .001)

g (SE) =  − 0.83 (0.24)

[39] (2019)

RCT

[Excellent]

OLP (n = 63): Open-label placebo pills, social learning with TAU

TAU (n = 59): Treatment as usual (TAU) patients received no intervention (no further description provided)

OLP + TAU:

Post: MΔ = –0.62

(± SE = 0.23)

TAU:

Post: MΔ = 0.11

(± SE = 0.17)

OLP + TAU > TAU

Post: (p = .001)

d = –0.44

OLP + TAU:

Post: MΔ = 23.21

(SE ± 1.59)

TAU:

Post: MΔ = 0.65

(± SE = 1.15)

OLP + TAU > TAU

Post: (p = .02)

d = –0.45

[40] (2016)

RCT

[Excellent]

OLP (n = 41): Open-label placebo pills, verbal suggestions, social learning with TAU

TAU (n = 42): Treatment as usual in an outpatient pain unit of a general public hospital (no further description of treatment provided)

OLP + TAU:

MΔ = 1.49 (± 1.68)

TAU:

MΔ = 0.24 (± 1.61)

OLP + TAU > TAU

Post: (p < .001)

g = 0.76

OLP + TAU:

MΔ = 2.86 (± 3.91)

TAU:

MΔ = 0.02 (± 3.73)

OLP + TAU > TAU

Post: (p < .001)

g = 0.74

[41] (2017)

RCT (Cluster)

[Excellent]

Communication Style and Exercise Compliance in Physiotherapy (CONNECT) (n = 108): Enhancing physiotherapists’ communication skills to alter unhelpful patient beliefs and improve motivation

TAU (n = 99): Treatment as usual; publicly funded physiotherapy with no restrictions on the number of sessions or the type of treatment the physiotherapist administered

CONNECT

Post:

MΔ = − 1.53 (± 2.71)

24 weeks:

MΔ = − 1.53 (± 2.78)

TAU

Post:

MΔ = − 1.31 (± 2.36)

24 weeks:

MΔ = − 1.18 (± 3.19)

CONNECT ~ TAU

(p = .75)

M_Diff = − 0.10

95% C.I. [− 0.71 to 0.51]

d = − 0.04

CONNECT

Post:

MΔ = − 3.48 (± 5.72)

24 weeks:

MΔ = − 4.87 (± 5.86)

TAU

Post:

MΔ = − 2.82 (± 5.77)

24 weeks:

MΔ = − 4.09 (± 5.95)

CONNECT ^a  ~ TAU

(p = .60)

M_Diff = − 0.36

95% C.I. [− 1.68–0.96]

d = − 0.08

[42] (2010)

RCT

[Good]

ED (n = 18): Pain biology education for the management of cLBP

Variation of CFs:

ED-EX (n = 20): Pain biology education plus six weekly exercise sessions (in a group format)

ED

Post: MΔ = − 30.9

ED-EX

Post: MΔ = − 4.2

ED > ED-EX

(p = .025)

ED

Post: MΔ = − 7.5

ED-EX

Post: MΔ = − 3.8

ED ~ ED-EX

(p = .127)

[43] (2020)

RCT

[Good]

OLP (n = 26): Open-label placebo pills, verbal suggestions, with TAU (advice, education, reassurance, self-management)

TAU (n = 26): Treatment as usual included advice to remain active, along with education and reassurance in addition to a psychological education self-management strategy to improve pain-related disabilities

OLP + TAU:

Post:

MΔ = –0.9 (± 1.8)

12-weeks:

MΔ = –1.1 (± 1.9)

TAU:

Post:

MΔ = –0.2 (± 1.8)

12-weeks:

MΔ = –0.8 (± 1.9)

OLP + TAU ~ TAU

Post: (p = .19)

d = 0.38

12-weeks: (p = .18)

η_p² = 0.04

OLP + TAU:

RMDQ: MΔ = –2.2 (± 2 .9) TUG: MΔ = –0.7 (± 1.0)

12-weeks:

RMDQ: MΔ = –3.3 (± 3.2)

TUG: MΔ = –0.62 (± 1.5)

TAU:

RMDQ: MΔ = –1.4 (± 3.6)

TUG: MΔ = –0.7 (± 1.5)

12-weeks:

RMDQ: MΔ = –2.3 (± 3.2)

TUG: MΔ = –1.1 (± 1.1)

OLP + TAU ~ TAU

RMDQ: (p = .40)

d = 0.24

TUG: (p = .98)

d = 0.01

12-weeks

RMDQ: (p = .37)

η_p² = 0.02

TUG: (p = .28)

η_p² = 0.03

[44] (2021)

RCT

[Good]

ED + TA (n = 74): Patient education (ED) relating to return to daily activities, advice on coping with pain, a clear explanation of signs and symptoms with an emphasis on increasing empathy and therapeutic alliance (TA)

Variation of CFs:

ED only (n = 74): the same structured patient education sessions (ED) but with no emphasis on enhancing the patient-practitioner relationship

No ED (n = 74): Patients received no-education and were advised not to seek treatment in the first month after randomisation

ED + TA vs ED only

Post: M_Diff = 0.09

6-mo: M_Diff = 0.61

1-year: M_Diff = − 0.02

ED + TA vs No ED

Post: M_Diff = 0.06

6-mo: M_Diff = − 0.05

1-year: M_Diff = 1.40

ED only vs No ED:

Post: M_Diff = 0.15

6-mo: M_Diff = 0.55

1-year: M_Diff = 1.37

ED + TA ~ ED only

ns: (p-values unreported)

ED + TA > No ED

1-year: (p < .05)

Post & 6-months: ns

ED only > No ED

1-year: (p < .05)

Post & 6-months: ns

Effect sizes unreported

M _Diff PSFS/ODI

ED + TA vs ED only

Post: M_Diff = 0.46/1.90

6-mo:M_Diff = 0.52/1.27

1-yr: M_Diff = 0.40/2.26

ED + TA vs No ED

Post: M_Diff = − 1.41/4.39

6-mo:M_Diff = − 1.21/5.30

1-yr: M_Diff = − 1.69/9.26

ED only vs No ED

Post: M_Diff = − 0.95/2.48

6-mo:M_Diff = − 0.68/4.02

1-yr: M_Diff = − 1.29/7.00

ED + TA ~ ED only

ns: (p-values unreported)

ED + TA > No ED

PSFS: ( p  < .05)

Post, 6-months, 1-year

ODI: ( p  < .05)

6-months, 1-year

ED only > No ED

PSFS: ( p  < .05)

Post, 1-year

ODI: ( p  < .05)

1-year

Effect sizes unreported

[45] (2017)

RCT

(2 × 2)

[Good]

Manipulating patient’s pain expectations using an inert solution/labelling, verbal instructions, and classical conditioning (CC)

Variation of CFs:

Opioid Instruction (OI) (Deceptive/Hidden)

With CC: (n = 12)

No CC: (n = 12)

Placebo Instruction (PI)

(Truthful/Open-Label)

With CC: (n = 12)

No CC: (n = 12)

Post: (Day 1)

Opioid Instruction

With CC:

M = 1.92 (± 1.73)

No CC:

M = 3.00 (± 2.73)

Placebo Instruction:

With CC:

M = 4.58 (± 2.31)

No CC:

M = 5.83 (± 1.95)

Deception > Truth

( p  =  < .01)*

Dose–response:

Deception (OI)

With CC: d = 1.83*

No CC: d = 0.83*

Truthful (PI)

With CC: d = 0.32; ns

No CC: d = − 0.64*

(nocebo effect)

Post: (Day 1)

Opioid Instruction

With CC:

M = 77.22 (± 15.43)

No CC:

M = 67.78 (± 29.24)

Placebo Instruction:

With CC:

M = 53.89 (± 24.03)

No CC:

M = 44.44 (± 15.66)

Deception > Truth

( p  =  < .01)*

Dose–response:

Deceptive: (OI)

With CC: d = − 0.92*

No CC: d = − 0.59*

Truthful: (PI)

With CC: d = − 0.17

No CC: d = 0.43

[46] (2019)

RCT

(2 × 2)

[Good]

Manipulating patient’s pain expectations using an inert drain dressing infusion with mirrors/labelling, verbal instructions, and either placebo or nocebo conditioning (PC or NC)

Variation of CFs:

Sham “Opioid” Infusion:

Placebo Conditioning (PC): (n = 17)

Sham only (SO): (n = 21)

Nocebo Conditioning (NC): (n = 21)

Natural History (NH): (n = 14) no sham infusion (waiting only) nor any classical conditioning

Post infusion: (Day 1)

PC: M = 3.24 (± 2.48)

SO: M = 2.43 (± 1.88)

NC: M = 3.57 (± 2.27)

NH: M = 5.00 (± 2.35)

Post infusion: (Day 8)

PC: M = 3.41 (± 2.52)

SO: M = 2.57 (± 2.22)

NC: M = 3.48 (± 2.18)

NH: M = 5.36 (± 1.98)

Sham Infusion > NH

PC & SO ( p  =  < .001)

NC ( p  =  < .01)

PC: η² = 0.38

SO: η² = 0.56

NC: η² = 0.21

NH: ( p  = .92)

NH: η² = 0.01

Post infusion: (Day 1)

PC: M = 72.54 (± 29.2)

SO: M = 77.46 (± 21.4)

NC: M = 73.33 (± 23.2)

NH: M = 54.76 (± 23.7)

Post infusion: (Day 8)

PC: M = 76.86 (± 29.2)

SO: M = 78.73 (± 22.5)

NC: M = 78.73 (± 18.0)

NH: M = 53.86 (± 23.0)

Sham Infusion > NH

SO ( p  =  < .01)

PC & NC ( p  =  < .05)

PC: η² = 0.15

SO: η² = 0.27

NC: η² = 0.20

NH: ( p  = .63)

NH: η² = 0.03

[47] (2017)

CCT

[Excellent]

Enhanced Transtheoretical Model Intervention (ETMI) (n = 94): focusing on therapists’ communication skills; improving TA using empathy, active listening; addressing low motivation, self-efficacy, and addressing maladaptive beliefs/behaviours

Conventional physical therapy (PT (n = 95)) treatments: mobilisation, manipulation, back exercises, postural training, back school, electrical stimulation, shortwave diathermy, cooling, and stretching

Average Pain

Post: MΔ = 0.6

95% C.I. [− 0.2 to 1.4]

Follow-up: MΔ = 0.9

95% C.I. [− 0.03 to 1.8]

Worst Pain

Post: MΔ = 0.10

95% C.I. [− 0.8 to 1.2]

Follow-up: MΔ = 1.2

95% C.I. [0.05 to 2.3]

ETMI ~ PT

Post: (p = .10)

Follow-up: (p = .06)

Worst pain

ETMI > PT

Post: (p = .70)

Follow-up: (p = .04)

Effect size unreported

Post: MΔ = 1.3,

95% C.I. [− 0.3 to 3.0]

Follow-up: MΔ = 2.7

95% C.I. [0.9 to 4.5]

ETMI ~ PT

Post: (p = .10)

ETMI > PT

Follow-up: (p = .004)

d = 0.54

[48] (2012)

CCT

[Good]

Intervention (n = 93) focused on patient’s illness and treatment beliefs and their information needs

TAU (n = 95): Treatment as usual; inpatient musculoskeletal rehabilitation which is typically multimodal and multidisciplinary

Intervention

M = 42.91 (± 21.50)

TAU

M = 42.26 (± 20.77)

Intervention ~ TAU

(p = .319)

Intervention

M = 30.98 (± 15.70)

Control

M = 31.46 (± 16.19)

Intervention ~ TAU

(p = .412)

[49] (2018)

CCT

[Fair]

Adding one weekly group-based physical therapy session in a rehabilitation setting compared to home treatment alone

Variation of CFs:

Rehab (n = 13): Weekly group-based physical therapy session involving exercises

Home (n = 17): No physical therapy supervision

Post-treatment

M_Diff = − 0.9

95% C.I. [− 2.3 to 0.5]

Rehab ~ Home

(p = .655)

Post-treatment

M_Diff = − 0.2

95% C.I. [− 3.8 to 3.3]

Rehab ~ Home

(p > 0.999)