Can nocebo effects on itch be modified by a positive expectation induction?

Completed

• Conditions: Itch; pruritus; 10014982

• Registration Number: NL-OMON40445
• Lead Sponsor: niversiteit Leiden

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Last Update Posted: 23 April 2024

Recruitment & Eligibility

• Status: Completed
• Sex: Not specified
• Target Recruitment: 99

Inclusion Criteria

Healthy human volunteers, 18 - 35 year old, fluent in Dutch language

Exclusion Criteria

Severe morbidity (e.g., multiple sclerosis, diabetes mellitus, heart or lung diseases), psychiatric disorders (e.g., depression), use of pacemaker, color-blindness, diagnose of histamine hypersensitivity, and chronic itch or pain complaints.

Study & Design

• Study Type: Observational non invasive
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
<p>The main study endpoint is the difference in the levels of itch (VAS scores)<br /><br>evoked by the electrical stimuli associated with the conditioned cues versus<br /><br>the neutral cues in the testing phase of part II of the experiment. It is<br /><br>investigated whether nocebo effects (negative expectation effects) can be<br /><br>modified by a positive expectation induction by conditioning and verbal<br /><br>suggestion (low-itch expectation induction) (group 1), resulting in lower itch<br /><br>VAS scores than a repeated negative expectation induction (high-itch<br /><br>expectation induction) (group 2), or a neutral procedure (neutral expectation<br /><br>induction) (group 3).</p><br>

Secondary Outcome Measures

Name	Time	Method
<p>The secondary study endpoints of the present experiment are: a) the itch<br /><br>related expectancy effects on scratching behavior; b) the itch related<br /><br>expectancy effects regarding itch evoked by histamine iontophoresis; c) the<br /><br>role of individual characteristics (e.g., optimism) on (the modifiability) of<br /><br>expectancy effects; and d) the role of 5-HTTLPR genotype and other genetic<br /><br>variants on (the modifiability) of expectancy effects. </p><br>