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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Are pills enough? The influence of information on open-label placebo effects in healthy volunteers
Scientific title
Open-label placebo administration, treatment information, and wellbeing in healthy participants
Secondary ID [1] 292520 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Negative emotional state 304161 0
Positive mental wellbeing 304162 0
Physical symptoms 304163 0
Sleep quality 304164 0
Condition category
Condition code
Alternative and Complementary Medicine 303491 303491 0 0
Other alternative and complementary medicine
Mental Health 303492 303492 0 0
Studies of normal psychology, cognitive function and behaviour

Study type
Description of intervention(s) / exposure
Open-label placebo administration (1 placebo pill per day, with either standard RCT placebo information versus enhanced open-label placebo information) for 5 days compared to a no treatment control condition. Adherence will be assessed via self-report at follow-up after completion of the course of placebo pills (day 6).

Enhanced information will follow the talking points outlined by Kaptchuk and colleagues (2010) - namely that placebos are powerful, can produce an automatic healing response, that positive expectations are not necessary but keeping an open mind is important, and that taking pills faithfully (i.e. adherence) is critical.

Standard RCT information is similar to that typically provided in RCT studies involving a placebo control condition. Namely, placebos will be described as typically being used as a control treatment, with the capsules containing inert ingredients that have no active physiological effect.

Information will be provided verbally to both groups during an initial half hour face-to-face research session. Information provision will take 5 to 10 minutes. At the end of this session, participants will be given lactose-filled vegetarian gelatin placebo capsules to take for the next 5 days.
Intervention code [1] 298704 0
Other interventions
Comparator / control treatment
No treatment control condition - control participants will not take placebo pills and will be observed only through completion of study questionnaires
Control group

Primary outcome [1] 302867 0
Negative emotional state: depression, anxiety, and stress symptoms (DASS-21; Lovibond & Lovibond, 1995)
Timepoint [1] 302867 0
Follow-up 6 days post-randomisation (at completion of the 5-day course of placebo pills)
Primary outcome [2] 302868 0
Physical symptoms (SHC; Eriksen, Ihlebaek & Ursin, 1999)
Timepoint [2] 302868 0
6 days post-randomisation (at completion of the 5-day course of placebo pills)
Primary outcome [3] 302869 0
Sleep quality (ISI, Morin, Belleville, Belanger, & Ivers, 2011)
Timepoint [3] 302869 0
6 days post-randomisation (at completion of the 5-day course of placebo pills)
Secondary outcome [1] 337269 0
Adherence to placebo treatment - assessed using brief self-report measures (number of pills missed, visual analog scale). On the VAS scale, participants will be asked to indicate how well they have adhered to the instructions to take one placebo pill per day, with response recorded on a VAS from 0 (not at all) to 10 (perfect adherence).
Timepoint [1] 337269 0
6 days post-randomisation (at completion of the 5-day course of placebo pills)
Secondary outcome [2] 337350 0
Positive mental wellbeing (WEMWBS; Tennant et al., 2007) - this is a fourth primary outcome.
Timepoint [2] 337350 0
6 days post-randomisation (at completion of the 5-day course of placebo pills)

Key inclusion criteria
Participants will be healthy undergraduate students
Minimum age
16 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Lactose intolerance

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation concealment via sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation table created by computer software (Excel)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
3-way ANCOVA assessing primary outcomes across groups, controlling for baseline

Regression analyses assessing the influence of expectations about and adherence to placebo treatment on primary outcomes, controlling for baseline

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 16715 0
2052 - Unsw Sydney

Funding & Sponsors
Funding source category [1] 297089 0
Name [1] 297089 0
University of New South Wales
Address [1] 297089 0
School of Psychology
UNSW Sydney
NSW 2052
Country [1] 297089 0
Primary sponsor type
Dr Kate Faasse
School of Psychology
UNSW Sydney
NSW 2052
Secondary sponsor category [1] 296097 0
Name [1] 296097 0
Address [1] 296097 0
Country [1] 296097 0

Ethics approval
Ethics application status
Ethics committee name [1] 298267 0
Ethics committee address [1] 298267 0
School of Psychology
UNSW Sydney
NSW 2052
Ethics committee country [1] 298267 0
Date submitted for ethics approval [1] 298267 0
Approval date [1] 298267 0
Ethics approval number [1] 298267 0
File 2770 (modification)

Brief summary
This study will investigate the role of information provision in open-label placebo administration. Recent studies have found that open-label placebo treatments are effective in improving symptoms of IBS, depression, ADHD, and low-back and migraine pain. These findings suggest the possibility of generating a placebo effect without deception. Participants will be recruited to take part in a study investigating the effect of open-label placebo administration on wellbeing and randomly assigned to one of three conditions: no-treatment control, standard RCT placebo information, or enhanced open-label placebo information.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 76530 0
Dr Kate Faasse
Address 76530 0
School of Psychology
UNSW Sydney
NSW 2052
Country 76530 0
Phone 76530 0
Fax 76530 0
Email 76530 0
Contact person for public queries
Name 76531 0
Dr Kate Faasse
Address 76531 0
School of Psychology
UNSW Sydney
NSW 2052
Country 76531 0
Phone 76531 0
Fax 76531 0
Email 76531 0
Contact person for scientific queries
Name 76532 0
Dr Kate Faasse
Address 76532 0
School of Psychology
UNSW Sydney
NSW 2052
Country 76532 0
Phone 76532 0
Fax 76532 0
Email 76532 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary