|- candidate number||27392|
|- NTR Number||NTR6530|
|- ISRCTN||ISRCTN no longer applicable|
|- Date ISRCTN created|
|- date ISRCTN requested|
|- Date Registered NTR||14-jun-2017|
|- Secondary IDs||NL58792.058.16 METC LUMC|
|- Public Title||Open and closed label nocebo and placebo|
|- Scientific Title||Effects of open and closed label nocebo and placebo verbal suggestions on itch|
|- ACRONYM||Open and closed label nocebo and placebo|
|- hypothesis||The primary objective of the study is to investigate whether negative and positive outcome expectations, induced by verbal suggestions under both open-label and closed-label conditions, can influence self-reported itch during a short-term validated histamine test. It is expected that negative outcome expectations will result in higher self-reported itch, whereas positive outcome expectations will result in lower self-reported itch. To investigate whether open-label verbal suggestions and closed-label verbal suggestions are separately able to induce outcome expectations and influence self-reported itch, separate analyses will be conducted for each labelled type of verbal suggestions. |
As a secondary objective, the effects of open- versus closed-label verbal suggestions both combined and separately on other outcome parameters (e.g., physical skin condition and self-reported skin condition) and the role of psychological parameters will be explored.
|- Healt Condition(s) or Problem(s) studied||Itch|
|- Inclusion criteria||1. Between 18 and 35 years old.|
2. Good understanding of written and spoken Dutch.
|- Exclusion criteria||1. Refusal to provide written informed consent.|
2. Severe somatic or psychological morbidity (e.g. heart and lung diseases or DSM-IV psychiatric disorders) that would adversely affect participantís safety or that might interfere with the study protocol.
3. Current chronic itch or pain complaints.
4. Recent use of analgesics, anti-inflammatory drugs, antihistamines, antibiotics or recent vaccinations.
|- mec approval received||yes|
|- multicenter trial||no|
|- Type||2 or more arms, randomized|
|- planned startdate ||20-okt-2016|
|- planned closingdate||31-jul-2017|
|- Target number of participants||92|
|- Interventions||Positive outcome expectations will be induced by verbal suggestions in the open- and closed-label positive verbal suggestions groups. Negative outcome expectations will be induced in the open- and closed-label negative verbal suggestions groups. |
Participants will be told that they will experience either less or more itch (the nature of the instructions varies depending on group allocation) during a short-term validated histamine test than during a previously conducted baseline session, as a result of a tonic that is applied to the skin prior to the test.
When verbal suggestions are given under open-label conditions, participants will receive additional information regarding the effects of expectations and verbal suggestions on itch. For example, they will be told about either the nocebo or placebo effect, depending on group allocation, and that verbal suggestions can influence experienced itch. When verbal suggestions are given under closed-label conditions, participants will be given verbal suggestions only; they will not receive further information regarding the effects of expectations on itch.
|- Primary outcome||The primary study outcome is the difference in self-reported itch rating during a short-term validated histamine test (histamine iontophoresis) between the combined open- and closed-label positive verbal suggestion group and the combined open- and closed-label negative verbal suggestion group. |
|- Secondary outcome||Secondary analyses will be conducted to examine the difference in self-reported itch between the negative and positive verbal suggestion groups separately for the open-label condition, and the closed-label condition. Negative and positive VS groups will additionally be compared on secondary outcome measures (e.g. self-reported skin condition). These analyses will be conducted for the open-label VS and closed-label VS groups combined as well as separately. In addition, the possible influence of psychological parameters on outcomes will be explored.|
|- Timepoints||The study consists of an online screening questionnaire, followed by two sessions. In the first week, a baseline session will be conducted. During the second week, an experimental session will be conducted in which participants receive verbal suggestions.|
|- Trial web site||n/a|
|- status||stopped: trial finished|
|- CONTACT FOR PUBLIC QUERIES||Prof. Dr. A.W.M. Evers|
|- CONTACT for SCIENTIFIC QUERIES||Prof. Dr. A.W.M. Evers|
|- Sponsor/Initiator ||Leiden University|
(Source(s) of Monetary or Material Support)
|European Research Council Consolidator Grant|
|- Brief summary||In the present study, the effects of negative and positive outcome expectations, induced by verbal suggestions under both open-label and closed-label conditions, on self-reported itch are studied. In a randomized controlled trial, participants will be screened by filling out an online questionnaire, and following inclusion, will be allocated to one of four study groups: 1) an open-label negative verbal suggestions group; 2) a closed-label negative verbal suggestions group; 3) an open-label positive verbal suggestions group; or 4) a closed-label positive verbal suggestions group. Participants will first take part in a baseline session, during which baseline measurements are conducted. In the next week, an experimental session will take place, during which participants will receive verbal suggestions. It is expected that both combined and separate closed- and open-label verbal suggestions will lead to either negative or positive outcome expectations that induce an increase or decrease (depending on group allocation) in self-reported itch following a short-term validated histamine test. Secondary outcomes include self-reported skin condition and physical skin condition (e.g. wheal size following histamine).|
|- Main changes (audit trail)|
|- RECORD||14-jun-2017 - 2-mei-2018|