What are the effects of an open-label placebo?

Examining side effects in healthy adults who have been administered an open-label placebo.

Status

Completed

Phases

Unknown

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12622001570774

Enrollment

Registered

2022-12-20

Start date

2023-02-22

Completion date

2023-03-15

Last updated

2023-12-12

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 study aims to determine whether participants report side effects after receiving an open-label placebo and whether side effects are attributed to the open-label placebo. It also determines which demographic and psychological characteristics are associated with the reporting of side effects. It is hypothesized that participants who receive an open-label placebo will report more side effects and decreased mood, compared to those who do not receive an open-label placebo. It is expected that these effects will remain at both 15 minutes and 24 hours follow-up. It is also hypothesized that demographic (i.e., female gender) and psychological characteristics at baseline (i.e., higher anxiety, perceived sensitivity to medicines and modern health worries) will be associated with increased reporting of side effects after taking an open-label placebo. This study will contribute to existing literature on open-label placebos by investigating their impact on side effects. Findings may also help to identify which patients are more vulnerable to developing nocebo responses to future treatments.

Interventions

There will be one 45-minute face-to-face session for the participants with the researcher. After completing the baseline questionnaire, all participants will receive a standardised explanation verbally about open-label placebos by the researcher. They will be informed about the effects a placebo might have and that they can either improve health outcomes or induce side effects. Participants will then be randomised into the experimental or control group. Participants in the experimental group will be asked to take a placebo pill consisting of microcrystalline cellulose. The researcher will supervise participants taking the placebo. In both conditions, participants will be asked to fill out two follow-up questionnaires, one 15 minutes after the intervention and the other one 24 hours after the intervention.

Study design

Allocation

Randomised controlled trial

Intervention model

Parallel

Primary purpose

Treatment

Masking

Open (masking not used)

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Healthy volunteers

Yes

Inclusion criteria

Participants are eligible to take part in this study if they are aged 18 years or older, able to fill out the questionnaires, willing to participate and fluent in the English language.

Exclusion criteria

None.

Outcome results