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Trial registered on ANZCTR


Registration number
ACTRN12619000726156
Ethics application status
Approved
Date submitted
29/03/2019
Date registered
14/05/2019
Date last updated
21/06/2022
Date data sharing statement initially provided
14/05/2019
Type of registration
Retrospectively registered

Titles & IDs
Public title
An experimental study of the influence of choice (versus no choice) of placebo treatment on reported side effects (nocebo effects) in healthy participants
Scientific title
An experimental study of the influence of choice (versus no choice) of placebo treatment on reported side effects (nocebo effects) in healthy participants
Secondary ID [1] 297833 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Anxiety 312203 0
Condition category
Condition code
Mental Health 310748 310748 0 0
Anxiety

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
There are 2 exposures in this study. First exposure to a placebo treatment described as a benzodiazepine (actually containing only lactose), compared to no exposure i.e. no treatment. Second, exposure to 1 of 3 treatment choice conditions (no choice of placebo treatments, choice of 2 placebo treatments, choice of 10 placebo treatments). Thus, participants will be randomly assigned to 1 of 4 conditions: 1) No treatment control, 2) No choice of placebo treatment, 3) Choice between two placebo treatments, 4) Choice between ten placebo treatments. All participants will be asked to complete an experimental anxiety induction (straw breathing task) in order to ostensibly assess the impact of the benzodiazepine (actually placebo) on anxiety. The intervention will be delivered by a university research student, in the research rooms of the UNSW Psychology Clinic.
Intervention code [1] 314070 0
Treatment: Other
Comparator / control treatment
The comparator is a no treatment control group. This group will undergo all other study procedures (questionnaires, brief anxiety-induction task, blood pressure and heart rate measurement), but will not be given a placebo treatment to take.

In addition, in order to assess the effect of choice on the nocebo effect, the no choice of placebo treatment group will form a second comparator condition. These participants will be randomly assigned a placebo treatment to take, and will complete all study procedures.
Control group
Active

Outcomes
Primary outcome [1] 319596 0
Nocebo effect - assessed via self-reported physical symptoms using the Generic Assessment of Side Effects Scale (1). This scale was designed to assess general drug side effects in clinical trials.

1. Rief W, Barsky AJ, Glombiewski JA, Nestoriuc Y, Glaesmer H, Braehler E. Assessing general side effects in clinical trials: reference data from the general population. Pharmacoepidemiol Drug Saf. 2011;20:405–15.
Timepoint [1] 319596 0
Primary time point: 30 minutes post-placebo administration (or equivalent time-point in the no treatment control condition)

Secondary time point: at 24-hour follow-up
Secondary outcome [1] 368830 0
Placebo effect - assessed via self-reported anxiety using the state version of the Speilberger State Trait Anxiety Inventory, as well as a single-item measure developed for this study asking participants "How anxious are you feeling right now"? This item is rated on a visual analogue scale from 0 (not anxious at all) to 10 (extremely anxious)
Timepoint [1] 368830 0
30 minutes post-placebo administration (or equivalent time-point in the no treatment control condition)
Secondary outcome [2] 370318 0
Heart rate measured using an Omron HEM-7130 Blood Pressure and Heart Rate Monitor
Timepoint [2] 370318 0
30 minutes post-placebo administration (or equivalent time-point in the no treatment control condition)
Secondary outcome [3] 370319 0
Blood pressure measured using an Omron HEM-7130 Blood Pressure and Heart Rate Monitor
Timepoint [3] 370319 0
30 minutes post-placebo administration (or equivalent time-point in the no treatment control condition)

Eligibility
Key inclusion criteria
Able to ingest ingredients of placebo capsules (lactose, gelatin). In line with cover story of a benzodiazepine treatment, participants must also not have any contraindications for benzodiazepine use or previous adverse reaction.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Unable to consume gelatine or lactose. Self-reported anxiety assessed as severe or extremely severe by DASS-21 anxiety subscale.

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)
Allocation concealment will be achieved using sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by the random number generator function in Microsoft Excel
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?


The people assessing the outcomes
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
In order to detect a medium-to-large effect size in the nocebo effect (f=.32; from Bartley et al., 2016), with an alpha level of 0.05 and power of 80%, an estimated 28 participants will be required per group, 112 participants in total.

Planned comparisons will be used to assess nocebo and placebo effect outcomes. To assess the overall presence of nocebo and placebo effects, the no treatment control condition will be compared to the placebo-treated groups. To assess the effect of choice, the no choice group will be compared to 1) the 2-choice group, and 2) the 10-choice group. To assess the effect of number of options, the 2-choice group will be compared to the 10-choice group.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
27/03/2019
Date of last participant enrolment
Anticipated
13/09/2019
Actual
13/08/2019
Date of last data collection
Anticipated
15/09/2019
Actual
14/08/2019
Sample size
Target
112
Accrual to date
Final
120
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 302355 0
Government body
Name [1] 302355 0
Australian Research Council
Country [1] 302355 0
Australia
Primary sponsor type
Individual
Name
Dr Kate Faasse
Address
School of Psychology
University of New South Wales
UNSW Sydney 2052
Country
Australia
Secondary sponsor category [1] 302251 0
None
Name [1] 302251 0
Address [1] 302251 0
Country [1] 302251 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 303029 0
The University of New South Wales Human Research Ethics Committee
Ethics committee address [1] 303029 0
Ethics committee country [1] 303029 0
Australia
Date submitted for ethics approval [1] 303029 0
27/10/2016
Approval date [1] 303029 0
22/11/2016
Ethics approval number [1] 303029 0
HC16864

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 92226 0
Dr Kate Faasse
Address 92226 0
School of Psychology
University of New South Wales
UNSW Sydney 2052
Country 92226 0
Australia
Phone 92226 0
+61 293850364
Fax 92226 0
Email 92226 0
[email protected]
Contact person for public queries
Name 92227 0
Kate Faasse
Address 92227 0
School of Psychology
University of New South Wales
UNSW Sydney 2052
Country 92227 0
Australia
Phone 92227 0
+61 293850364
Fax 92227 0
Email 92227 0
[email protected]
Contact person for scientific queries
Name 92228 0
Kate Faasse
Address 92228 0
School of Psychology
University of New South Wales
UNSW Sydney 2052
Country 92228 0
Australia
Phone 92228 0
+61 293850364
Fax 92228 0
Email 92228 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Participant-level data will not be made publicly available for this experimental study.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.