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Trial registered on ANZCTR

Registration number

ACTRN12620001080910

Ethics application status

Approved

Date submitted

20/08/2020

Date registered

20/10/2020

Date last updated

9/02/2025

Date data sharing statement initially provided

20/10/2020

Type of registration

Prospectively registered

Titles & IDs

Public title

Open-label placebo for insomnia (OPIN)

Scientific title

Open-label placebo for insomnia (OPIN): a cohort multiple randomized controlled trial in adults with moderate or severe insomnia

Secondary ID [1]

None

Universal Trial Number (UTN)

U1111-1244-9305

Trial acronym

OPIN

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Insomnia

Condition category

Condition code

Mental Health

Other mental health disorders

Neurological

Other neurological disorders

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Participants with insomnia symptoms are initially recruited to a large observational cohort to measure changes in insomnia symptoms over a 4-week period as an outcome variable. After two weeks of this observation period, participants will be randomised to one of three different arms. Participants randomized into arm 1 will receive an invite to trial open-label placebo, those in arm 2 will receive an invite to trial conventional placebo, and a third arm will receive no invite (observational control).
In both arm 1 and arm 2, the investigational product is placebo capsules (i.e. capsules containing microcrystalline cellulose). Participants are instructed to take 2 capsules (oral) per day for 2 weeks, 10-15 minutes before they go to bed.
Participants in arm 1 (open-label placebo) are informed that the capsules are placebo capsules (i.e. they contain an inert agent), but provided with a brief rationale as to how placebos may be effective.
Participants in arm 2 (conventional placebo) are informed that the capsules are a new pharmacological agent [7 digit code name] that can reduce insomnia symptoms, and provided with a brief rationale as to how this drug may be effective.
Adherence with placebo capsules will be assessed by asking participants to self-report whether and when they took their capsules each day, as part of a sleep diary. Participants will also be asked to return any unused capsules to their final study site visit.

Intervention code [1]

Treatment: Other

Comparator / control treatment

The control group is a no-treatment control.

Control group

Active

Outcomes

Primary outcome [1]

Changes in self-reported insomnia symptoms, measured using the Insomnia Severity Index (ISI).

Timepoint [1]

Screening, Baseline (Day 14) and Post-treatment (Day 28)

Secondary outcome [1]

Rate of uptake of open-label placebo relative to conventional placebo. Rate of uptake of open-label will be measured as the proportion of participants whose written consent to participate in this treatment arm is obtained, relative to the number of participants randomly allocated and invited to participate in this treatment arm. Similarly, rate of uptake to conventional placebo will be measured as the proportion of participants who consent to participate relative to the number of participants invited to participate in this treatment arm.

Timepoint [1]

Baseline (randomisation, Day 14)

Secondary outcome [2]

Changes in objective sleep parameters, calculated from sleep-wake data collected with an actigraphy watch

Timepoint [2]

Daily from Enrolment (Day 1) to Baseline (Day 14). Daily from Baseline (Day 14) to Post-treatment (Day 28)

Secondary outcome [3]

Changes in subjective sleep parameters, assessed using the Consensus Sleep Diary (CSD)

Timepoint [3]

Daily from Enrolment (Day 1) to Baseline (Day 14) Daily from Baseline (Day 14) to Post-treatment (Day 28)

Secondary outcome [4]

Changes in daytime fatigue, measured using the Fatigue Symptom Inventory (FSI)

Timepoint [4]

Baseline (Day 14) and Post-treatment (Day 28)

Secondary outcome [5]

Changes in depression, measured using the Depression, Anxiety Stress Scales - 21(DASS-21)

Timepoint [5]

Baseline (Day 14) and Post-treatment (Day 28)

Secondary outcome [6]

Changes in anxiety, measured using the Depression, Anxiety Stress Scales - 21(DASS-21)

Timepoint [6]

Baseline (Day 14) and Post-treatment (Day 28)

Secondary outcome [7]

Changes in stress, measured using the Depression, Anxiety Stress Scales - 21(DASS-21)

Timepoint [7]

Baseline (Day 14) and Post-treatment (Day 28)

Secondary outcome [8]

Changes in Expectancy, measured by purpose-built Expectancy Measure

Timepoint [8]

Baseline, post-randomisation (Day 14) and Post-treatment (Day 28)

Secondary outcome [9]

Changes in treatment satisfaction, measured using the Treatment Satisfaction Questionnaire for Medication - II (TSQM-II).

Timepoint [9]

Post-treatment (Day 28)

Secondary outcome [10]

Self-reported side effects, measured using the Generic Assessment of Side Effects (GASE). No known or possible side effects are expected given the treatment is placebo.

Timepoint [10]

Post-treatment (Day 28)

Eligibility

Key inclusion criteria

- Adults (age 18 and above)
- Reporting insomnia symptoms of moderate or greater severity (score on the ISI >= 10)
- Ability and willingness to comply with study protocol
- Proficient in English

Minimum age

18 Years

Maximum age

No limit

Sex

Both males and females

Can healthy volunteers participate?

Key exclusion criteria

- Sleep disorder other than insomnia (e.g. sleep apnoea).
- Serious medical illness requiring invasive treatment/surgery (e.g. cancer) or heavy substance use
- Severe psychiatric comorbidity (e.g. psychosis) or risk of self harm or suicidality
- Currently taking regular (i.e. >=1/week) medication for sleep (including prescription and over-the-counter medications, herbal supplements, homeopathic formulations)
- Current psychological treatment for sleep
- Currently pregnant, planning a pregnancy in the next 3 months, breastfeeding or post-partum < 1 year
- Currently undertaking regular shift work
- Intending to travel to a destination >2 hours’ time difference in the next 3 months

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)

Central randomisation by computer

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Computer-generated randomisation table

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Parallel

Other design features

Cohort multiple randomised controlled trial design(cmRCT), All participants enter 2 week observational period, followed by randomisation into one of 3 different groups/arms: open-label placebo, conventional (deceptive) placebo, or observational control.

Phase

Not Applicable

Type of endpoint/s

Efficacy

Statistical methods / analysis

To detect an effect size for open-label placebo versus conventional placebo of d=.5, 64 participants in each placebo arm is required to achieve 80% power with alpha=.05. Using an allocation of 2:2:1, a total of 160 participants is required. However, as a 2-stage consent process is employed with a cmRCT design, there is the likelihood that some participants who consent to the first stage (observation) will not accept the invitation to receive treatment (open-label or conventional placebo) in the second stage. To ensure an adequate sample size is obtained in the treatment arms, we will therefore recruit until we have at least 64 participants who accept the invitation to each of the treatment arms.

Primary, Intention-to-treat (ITT) analysis will be used to compare effects of each group (open-label, conventional, observational control) on insomnia symptoms. Primary endpoint (mean ISI scores post-treatment) will be assessed using a mutlilevel model with group and baseline ISI score inluded as factors. Sensitivity analysis, using a per-protocol approach will be implemented as a secondary analysis and include only those participants who complete the study.

Chi-squared independence test will be used to determine differences in uptake to open-label versus conventional placebo treatment.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

2/11/2020

Actual

1/04/2021

Date of last participant enrolment

Anticipated

31/05/2024

Actual

16/09/2024

Date of last data collection

Anticipated

21/06/2024

Actual

16/10/2024

Sample size

Target

192

Accrual to date

Final

235

Recruitment in Australia

Recruitment state(s)

NSW

Funding & Sponsors

Funding source category [1]

University

Name [1]

The University of Sydney

Address [1]

School of Psychology, A18 University of Sydney NSW 2006

Country [1]

Australia

Primary sponsor type

University

Name

The University of Sydney

Address

University of Sydney
NSW 2006

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

The University of Sydney Human Research Ethics Committee

Ethics committee address [1]

University of Sydney
NSW 2006

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

22/05/2019

Approval date [1]

06/09/2019

Ethics approval number [1]

2019/552

Summary

Brief summary

There has been growing interest in whether open-label placebo (i.e. placebos given honestly) can improve health outcomes. Some studies have shown that open-label placebo is effective for conditions such as depression and chronic pain. This study aims to test whether open-label placebos can improve insomnia symptoms, compared to conventional placebos and a no-treatment control condition. We are using an innovative trial design, called a multiple cohort randomized controlled trial, to overcome some of the issues with current research into open-label placebos. Using this design, we will also be able to find out how many people with insomnia would accept open-label or conventional (deceptive) placebo treatment.

Trial website

https://www.sydneysleepstudy.com

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

A/Prof Ben Colagiuri

Address

A19 - Griffith Taylor The University of Sydney NSW 2006 Australia

Country

Australia

Phone

+61 2 93514589

Fax

[email protected]

Contact person for public queries

Name

Ben Colagiuri

Address

A19 - Griffith Taylor The University of Sydney NSW 2006 Australia

Country

Australia

Phone

+61 2 93514589

Fax

[email protected]

Contact person for scientific queries

Name

Ben Colagiuri

Address

A19 - Griffith Taylor The University of Sydney NSW 2006 Australia

Country

Australia

Phone

+61 2 93514589

Fax

[email protected]

Data sharing statement

Will the study consider sharing individual participant data?

Yes

Will there be any conditions when requesting access to individual participant data?

Persons/groups eligible to request access:
• Researchers providing a methodologically and ethically sound proposal.

Conditions for requesting access:
• -

What individual participant data might be shared?

• De-identified participant data collected during the trial.

What types of analyses could be done with individual participant data?

• Any types of analyses.

When can requests for individual participant data be made (start and end dates)?

From:
Immediately following publication of study results with no end date determined.

To:
-

Where can requests to access individual participant data be made, or data be obtained directly?

• Data can be obtained by contacting the principal investigator, A/Prof Ben Colagiuri at [email protected].

Are there extra considerations when requesting access to individual participant data?

What supporting documents are/will be available?

Doc. No.	Type	Email
14130	Study protocol	[email protected]
14131	Statistical analysis plan	[email protected]
14132	Analytic code	[email protected]

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Open-label placebo for insomnia (OPIN): Study protocol for a cohort multiple randomised controlled trial.	2021	https://dx.doi.org/10.1136/bmjopen-2020-044045

N.B. These documents automatically identified may not have been verified by the study sponsor.

Trial Review

Documents added manually

Documents added automatically