The influence of open-label placebos on cognitive performance

The influence of open-label placebos on cognitive performance - OLP CoPe

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

DRKS

Registry ID

DRKS00019203

Enrollment

200

Registered

2019-10-30

Start date

2019-11-04

Completion date

Unknown

Last updated

2025-04-07

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

Conditions

Healthy volunteers

Interventions

Group 1: The subjects receive no intervention after randomization but a 3-week observation (Control group). Group 2: The subjects receive a 3-weeks self administered Placebo-application in form of ora

Eligibility

Sex/Gender

All

Age

18 Years to 60 Years

Inclusion criteria

Inclusion criteria: Volunteers, informed consent to study participation

Exclusion criteria

Exclusion criteria: 1) Severe medical conditions (in particular, diagnosed psychiatric comorbidities); 2) Dyschromatopsia; 3) Harmful substance abuse (including alcohol, cannabinoids, cocaine, amphetamines) in the last 4 weeks prior to inclusion or persistence; 4) alcohol consumption on the day prior to T0 or T1; 5) Known allergy or intolerance to any of the ingredients of the placebo; 6) Parallel participation in a study using investigational medicinal products; 7) pregnancy, breastfeading

Design outcomes

Primary

Measure	Time frame
Primary outcome variables are measures of cognitive performance prior to and after a 3 week intake of placebo (OLP-group) or no intervention (control group) as assessed with different computerized, well-established cognitive tests: (I) Instrumental learning: Two symbols will be presented on a computer screen. One symbol is associated with gaining or losing money, while the other symbol is associated with no loss/gain of money. Participants are asked to maximize their gain of money by learning the correct associations of symbols and their outcome. Dependent variable is the increase of correct decisions per condition (gain/loss) assessed over the course of the experiment (i.e. learning curve). (II) Stroop task: Participants are asked to indicate the font color of a color word. Dependent variables are reaction time differences between congruent and incongruent trials (= stroop effect), indicative of the subjective color-word-interference susceptibility. (III) N-Back task: Here, a stream of letters will be presented on a computer screen. Participants are asked to press a button as fast as possible whenever a letter (target) is in accordance with the second to the last letter. Dependent variables are the number of correctly detected targets as well as mean reaction times of correctly detected targets. (IV) Divided attention: Participants are asked to pay attention to visual and auditory stimuli at the same time and to detect specific visual patterns and sequences of sounds (targets). Dependent variables are the number of correctly detected targets in each category (visual, auditory) as well as mean reaction times of correctly detected targets. In addition to these objective cognitive parameters we will assess subjective changes in cognitive performance on T1 using visual analogue scales.	—

Measure

Time frame

Primary outcome variables are measures of cognitive performance prior to and after a 3 week intake of placebo (OLP-group) or no intervention (control group) as assessed with different computerized, well-established cognitive tests: (I) Instrumental learning: Two symbols will be presented on a computer screen. One symbol is associated with gaining or losing money, while the other symbol is associated with no loss/gain of money. Participants are asked to maximize their gain of money by learning the correct associations of symbols and their outcome. Dependent variable is the increase of correct decisions per condition (gain/loss) assessed over the course of the experiment (i.e. learning curve). (II) Stroop task: Participants are asked to indicate the font color of a color word. Dependent variables are reaction time differences between congruent and incongruent trials (= stroop effect), indicative of the subjective color-word-interference susceptibility. (III) N-Back task: Here, a stream of letters will be presented on a computer screen. Participants are asked to press a button as fast as possible whenever a letter (target) is in accordance with the second to the last letter. Dependent variables are the number of correctly detected targets as well as mean reaction times of correctly detected targets. (IV) Divided attention: Participants are asked to pay attention to visual and auditory stimuli at the same time and to detect specific visual patterns and sequences of sounds (targets). Dependent variables are the number of correctly detected targets in each category (visual, auditory) as well as mean reaction times of correctly detected targets. In addition to these objective cognitive parameters we will assess subjective changes in cognitive performance on T1 using visual analogue scales.

—

Secondary

Measure	Time frame
Secondary outcome parameters will be assessed, in particular psychophysiological parameters such as stress, sleep quality and mood using standardized questionnaires (GASE, PSQI, STADI, PSQ20, POMS).	—

Countries

Germany

Contacts

Public ContactJohanna Albers

Universitätsklinik Essen AöR Klinik für Neurologie

johanna.albers@uk-essen.de+49 201 723 83744

Outcome results

None listed

Source: DRKS (via WHO ICTRP) · Data processed: Feb 4, 2026