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What are the effects of an open-label placebo on pain?

What are the effects of an open-label placebo on pain? A three-arm parallel randomised controlled trial on healthy adults.

Status
Not yet recruiting
Phases
Unknown
Study type
Interventional
Source
ANZCTR
Registry ID
ACTRN12623000801617
Enrollment
42
Registered
2023-07-26
Start date
2023-07-31
Completion date
2023-09-11
Last updated
2023-08-02

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

This research aims to investigate whether a participant's openness to treatment can enhance the pain-reducing effects of an open-label placebo (OLP). An OLP is a placebo where participants know they're receiving a non-active treatment, removing the deception involved in traditional placebos. Our study hypothesises that individuals receiving OLP will experience less experimental pain, measured via a cold pressor task, compared to a control group. Further, we expect that participants who receive an openness-enhancing rationale along with the OLP will report even less pain. This study contributes to ongoing research on open-label placebos, aiming to understand and potentially enhance their beneficial effects. Findings could help optimise OLP use in pain management, maintaining ethical standards and patient trust.

Interventions

There will be one 45-minute session for the participants with the researcher. After completing the baseline questionnaire, participants will be randomised to three conditions. Arm 1: Control group, receives no placebo pills and no explanation about placebos. Arm 2: Experimental group, will be asked to take two placebo pills containing microcrystalline cellulose while supervised by the researcher. A standard verbal explanation about open-label placebos will be given by the researcher, explain

There will be one 45-minute session for the participants with the researcher. After completing the baseline questionnaire, participants will be randomised to three conditions. Arm 1: Control group, receives no placebo pills and no explanation about placebos. Arm 2: Experimental group, will be asked to take two placebo pills containing microcrystalline cellulose while supervised by the researcher. A standard verbal explanation about open-label placebos will be given by the researcher, explaining the effects a placebo might have in reducing their pain. This explanation will take approximately 15 minutes. Arm 3: Experimental group, will be asked to take two placebo pills containing microcrystalline cellulose while supervised by the researcher. A standard verbal explanation about open-label placebos will be given by the researcher, explaining the effects a placebo might have in reducing their pain. In addition to this, they have a short additional explanation suggesting them to keep an open mind about the treatment. This explanation will take approximately 15 minutes, with the additional explanation by the researcher suggesting the participant keep an open mind taking approximately 30 seconds. After being randomised and undergoing their conditions, all participants will be asked to fill out a post-allocation questionnaire. After this, all participants will undergo a cold pressor pain test which involves placing one of their hands into water cooled to 3 degrees. During the test they will be assessed for pain intensity, pain tolerance (how long they keep their hand in), whether they remove their hand before the maximum time, and pain threshold (time until first feel pain).

Sponsors

The University of Auckland
Lead SponsorUniversity

Study design

Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Caregiver)

Eligibility

Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

To be eligible for the study, participants must be English-speaking adults aged 18 or over, who are willing to undergo an experimentally induced pain paradigm.

Exclusion criteria

Participants will be excluded if they have chronic pain conditions, cognitive impairment, lack of sensation in hands, open sores, amputations, health issues that may be exacerbated by cold-exposure, or who are currently taking pain medication.

Outcome results

None listed

Source: ANZCTR · Data processed: Feb 4, 2026