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Trial registered on ANZCTR


Registration number
ACTRN12618001175268
Ethics application status
Approved
Date submitted
11/07/2018
Date registered
16/07/2018
Date last updated
29/03/2019
Date data sharing statement initially provided
29/03/2019
Date results information initially provided
29/03/2019
Type of registration
Retrospectively registered

Titles & IDs
Public title
Mechanisms of Mindfulness Meditation for Experimental Pain
Scientific title
A randomized controlled trial comparing the effects of mindfulness vs sham mindfulness on experimental pain intensity and unpleasantness in healthy adults
Secondary ID [1] 295521 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Pain 308785 0
Condition category
Condition code
Musculoskeletal 307722 307722 0 0
Other muscular and skeletal disorders
Alternative and Complementary Medicine 307723 307723 0 0
Other alternative and complementary medicine
Anaesthesiology 307762 307762 0 0
Pain management

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Six, 20-minute guided-audio-delivered mindfulness meditation training sessions (over a 7-10 day period) of either:

(1) mindfulness meditation – “focussed attention” mindfulness meditation technique taught as means to reduce pain intensity and unpleasantness.

or

(2) sham (placebo) mindfulness meditation – all features of the training sessions match the real mindfulness meditation intervention but lack the proposed “active ingredient” of the training (the practice does not provide an anchor for attention or instructions on how to relate mindfully to present moment experience). Delivered as a means to elicit placebo-mediated (but not mindfulness-mediated) reductions in pain intensity and unpleasantness.

or

(3) natural history control group – this group completes no training. They listen to a podcast about meditation and society (abridged to 20-minutes) at baseline (This American Life - Psychic Buddha; https://www.thisamericanlife.org/212/the-other-man/act-one-0) and post-test (ABC Radio National - Who Owns Mindfulness?; http://www.abc.net.au/radionational/programs/earshot/who-owns-mindfulness/9024864) to maintain experimenter blinding only. So as not to manipulate participant expectancy, these podcasts do not discuss any benefits of mindfulness.

Each participant receives 2 training sessions in-lab at baseline and post-test, and is asked to complete 4 training sessions at home in between experimental sessions. Home guided-audio training is delivered via online survey software and adherence is monitored. All guided-training sessions are delivered by a qualified mindfulness instructor with 4+ years’ experience.
Intervention code [1] 301832 0
Treatment: Other
Comparator / control treatment
sham mindfulness meditation; no-treatment control group
Control group
Placebo

Outcomes
Primary outcome [1] 306706 0
Pain intensity, assessed via a numerical rating scale
Timepoint [1] 306706 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)
Primary outcome [2] 306707 0
Pain unpleasantness, assessed via a numerical rating scale
Timepoint [2] 306707 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)
Secondary outcome [1] 349307 0
Pain threshold, assessed using pain threshold test (Pathway CHEPS, Medoc, Israel).
Timepoint [1] 349307 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)
Secondary outcome [2] 349308 0
Pain tolerance, assessed using pain tolerance test (Pathway CHEPS, Medoc, Israel).
Timepoint [2] 349308 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)
Secondary outcome [3] 349309 0
Mindfulness, assessed via the FFMQ
Timepoint [3] 349309 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)
Secondary outcome [4] 349310 0
Depression, assessed via the DASS-21
Timepoint [4] 349310 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)
Secondary outcome [5] 349311 0
Anxiety, assessed via the DASS-21
Timepoint [5] 349311 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)
Secondary outcome [6] 349312 0
Stress, assessed via the DASS-21
Timepoint [6] 349312 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)
Secondary outcome [7] 349313 0
Pain related cognitive processes, assessed via the PCPQ
Timepoint [7] 349313 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)
Secondary outcome [8] 349314 0
Expectancy, assessed via self-report questions
Timepoint [8] 349314 0
Pre to post-treatment, i.e., baseline and after 6 sessions of training (1 week)

Eligibility
Key inclusion criteria
(1) at least 18 years of age; (2) pain-free (defined as 3/10 or lower on NRS); (3) not currently taking analgesic or psychotropic medications; (4) be able to read, speak and understand English; and (5) be able to attend two experimental sessions over 2 consecutive weeks and four sessions of home-practice.
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
(1) currently taking analgesic or psychotropic medications; (2) current pain higher than 3/10 on NRS; (3) pregnant or breastfeeding; (4) current mindfulness or meditation practice (average >20 min/week in last six months); (5) previously completed a mindfulness course (e.g. MBSR, Vipassana); and (6) practicing a meditation-based religion (e.g. Hinduism, Buddhism, contemplative Christianity);

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computerised random sequence generation (https://www.randomizer.org/) with numbers generated using a complex algorithm seeded by the computer's clock.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
SAMPLE SIZE CALCULATIONS
Power analyses were based on the effect sizes for mindfulness versus either sham mindfulness or natural history control from six recent studies on experimentally-induced pain (Kingston, Chadwick, Meron, & Skinner, 2007; Liu, Wang, Chang, Chen, & Si, 2013; MacCoon et al., 2012; Zeidan, 2016; Zeidan et al., 2011, 2015). These studies had a mean effect size of d=0.899 for pain unpleasantness and d=0.514 for pain intensity. To be conservative, we used the smaller of these (i.e. d=0.514) to calculate sample size. This indicated that 28 participants per group would be required to have 90% power to detect a significant effect of mindfulness versus sham mindfulness of this magnitude. We therefore aim to recruit 30 participants per group to allow for 5-10% attrition.

BASELINE CHARACTERISTICS
Chi-squared tests and independent samples t-tests will be used to compare baseline characteristics across the three groups.

PRIMARY AND SECONDARY OUTCOMES
Changes in primary and secondary outcome measures between the pre and post-treatment phases will be analysed using 3 (mindfulness, sham mindfulness, natural history control) x 2 (baseline, post-treatment) mixed model ANCOVAs, followed by pairwise comparisons of the three groups. Baseline characteristics that have a p-value of <0.1 when comparing the three groups will be included as covariates in these analyses.

EXPLORATORY MEDIATOR ANALYSIS
Where any significant differences are found between the three groups on primary (pain) outcomes, we will conduct exploratory mediator analysis to determine whether mindfulness, depression, anxiety, stress, pain related cognitive processes or expectancy mediate the effect of the intervention on those primary outcomes. This will be implemented via Preacher and Hayes/PROCESS Model.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment postcode(s) [1] 23339 0
2006 - The University Of Sydney

Funding & Sponsors
Funding source category [1] 300023 0
University
Name [1] 300023 0
The University of Sydney
Address [1] 300023 0
The University of Sydney
Camperdown NSW 2006
Country [1] 300023 0
Australia
Primary sponsor type
University
Name
The University of Sydney
Address
The University of Sydney
Camperdown NSW 2006
Country
Australia
Secondary sponsor category [1] 299503 0
None
Name [1] 299503 0
Address [1] 299503 0
Country [1] 299503 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 300874 0
University of Sydney Human Research Ethics Committee
Ethics committee address [1] 300874 0
Human Ethics Office
Margaret Telfer Building (K07)
University of Sydney
Camperdown NSW 2006
Ethics committee country [1] 300874 0
Australia
Date submitted for ethics approval [1] 300874 0
10/07/2017
Approval date [1] 300874 0
08/09/2017
Ethics approval number [1] 300874 0
2017/640

Summary
Brief summary
As many as 1 in 4 Australians experience chronic pain. There is a critical need for the development and evaluation of fast-acting non-pharmaceutical treatments that have the capacity to target the multidimensional nature of chronic pain. This study will compare the effects and mechanisms of mindfulness meditation against placebo and no-treatment control groups. Results will ultimately lead to targeted interventions that more effectively engage cognitive mechanisms associated with pain attenuation.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 85118 0
Mr Jonathan Davies
Address 85118 0
TSB241 Top South Badham Building (A16)
School of Psychology
The University of Sydney
Camperdown NSW 2006
Country 85118 0
Australia
Phone 85118 0
+61 2 9351 7950
Fax 85118 0
Email 85118 0
j.davies@sydney.edu.au
Contact person for public queries
Name 85119 0
Mr Jonathan Davies
Address 85119 0
TSB241 Top South Badham Building (A16)
School of Psychology
The University of Sydney
Camperdown NSW 2006
Country 85119 0
Australia
Phone 85119 0
+61 2 9351 7950
Fax 85119 0
Email 85119 0
j.davies@sydney.edu.au
Contact person for scientific queries
Name 85120 0
Mr Jonathan Davies
Address 85120 0
TSB241 Top South Badham Building (A16)
School of Psychology
The University of Sydney
Camperdown NSW 2006
Country 85120 0
Australia
Phone 85120 0
+61 2 9351 7950
Fax 85120 0
Email 85120 0
j.davies@sydney.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
We do not have ethics approval to share data. We are seeking a modification to share IPD and will update at that time.
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
No
Other publications
Have study results been made publicly available in another format?
No
Results – basic reporting
Results – plain English summary