Clinical Trial Results:
The effect of dopamine on reading motivation and achievement.
|
Summary
|
|
EudraCT number |
2014-001352-36 |
Trial protocol |
NL |
Global end of trial date |
17 Jul 2017
|
|
Results information
|
|
Results version number |
v1(current) |
This version publication date |
14 Jan 2022
|
First version publication date |
14 Jan 2022
|
Other versions |
|
Summary report(s) |
Swart & Sikkema-de Jong (2021) - Current Psychology |
Trial Information
Subject Disposition
Baseline Characteristics
End Points
Adverse Events
More Information
Subject Disposition
Baseline Characteristics
End Points
Adverse Events
More Information
|
|||
|
Trial identification
|
|||
Sponsor protocol code |
DOPAREAD1
|
||
|
Additional study identifiers
|
|||
ISRCTN number |
- | ||
US NCT number |
- | ||
WHO universal trial number (UTN) |
- | ||
|
Sponsors
|
|||
Sponsor organisation name |
Leiden University
|
||
Sponsor organisation address |
Wassenaarseweg 52, Leiden, Netherlands, 2333AK
|
||
Public contact |
Dr. E.K. Swart, Leiden University, e.k.swart@fsw.leidenuniv.nl
|
||
Scientific contact |
Dr. E.K. Swart, Leiden University, e.k.swart@fsw.leidenuniv.nl
|
||
|
Paediatric regulatory details
|
|||
Is trial part of an agreed paediatric investigation plan (PIP) |
No
|
||
Does article 45 of REGULATION (EC) No 1901/2006 apply to this trial? |
No
|
||
Does article 46 of REGULATION (EC) No 1901/2006 apply to this trial? |
No
|
||
|
Results analysis stage
|
|||
Analysis stage |
Final
|
||
Date of interim/final analysis |
11 Dec 2018
|
||
Is this the analysis of the primary completion data? |
Yes
|
||
Primary completion date |
17 Jul 2017
|
||
Global end of trial reached? |
Yes
|
||
Global end of trial date |
17 Jul 2017
|
||
Was the trial ended prematurely? |
No
|
||
|
General information about the trial
|
|||
Main objective of the trial |
The main goal of the study is to investigate if small amounts of dopamine could influence engagement during reading, comprehension of the story and vocabulary learning and to investigate if the effect of dopamine is different for carriers of the long or short variant of the DRD4 gene. Additionally, the effect of dopamine on how participants value reading is investigated.
|
||
Protection of trial subjects |
Students with dyslexia, medical illnesses indicating a risk in using haloperidol (e.g. cardiac illness, depression, thyroid disorders, or glaucoma), or known drug allergies were excluded from participation in the study. Also students were excluded if they were using medication (other than contraceptives) or drugs in the two weeks prior to the experiment or if they were pregnant or lactating during the experiment.
During study sessions participants were constantly accompanied by a researcher. Participants were informed beforehand that side-effects of the one-time administration of the drug were unlikely to occur, but that they should tell the researcher immediately if they thought they would possibly suffer from side-effects.
|
||
Background therapy |
- | ||
Evidence for comparator |
- | ||
Actual start date of recruitment |
01 Nov 2014
|
||
Long term follow-up planned |
No
|
||
Independent data monitoring committee (IDMC) involvement? |
No
|
||
|
Population of trial subjects
|
|||
Number of subjects enrolled per country |
|||
Country: Number of subjects enrolled |
Netherlands: 80
|
||
Worldwide total number of subjects |
80
|
||
EEA total number of subjects |
80
|
||
Number of subjects enrolled per age group |
|||
In utero |
0
|
||
Preterm newborn - gestational age < 37 wk |
0
|
||
Newborns (0-27 days) |
0
|
||
Infants and toddlers (28 days-23 months) |
0
|
||
Children (2-11 years) |
0
|
||
Adolescents (12-17 years) |
0
|
||
Adults (18-64 years) |
80
|
||
From 65 to 84 years |
0
|
||
85 years and over |
0
|
||
|
||||||||||
|
Recruitment
|
||||||||||
Recruitment details |
A total number of 200 undergraduate students from universities in the Netherlands signed up for participation in our study. After genotyping, 80 students (40 carriers of the DRD4-7r allele, and 40 participants who did not) were selected to participate in the experimental sessions. Recruitment took place between in 2015 and 2016. | |||||||||
|
Pre-assignment
|
||||||||||
Screening details |
Inclusion criteria: Women, 18 years or older, right-handed. Exclusion criteria: Dyslexia, medical illnesses indicating a risk in using haloperidol (e.g. cardiac illness, depression, thyroid disorders, or glaucoma), known drug allergies, using medication or drugs in the two weeks prior, pregnancy or lactating during the experiment | |||||||||
|
Period 1
|
||||||||||
Period 1 title |
Experimental sessions (overall period)
|
|||||||||
Is this the baseline period? |
Yes | |||||||||
Allocation method |
Randomised - controlled
|
|||||||||
Blinding used |
Double blind | |||||||||
Roles blinded |
Subject, Investigator | |||||||||
Blinding implementation details |
To ensure that the study design was double-blind, randomization of the order of treatments (Sinemet125 or placebo) and the order of texts that were read in both experimental sessions (text A and text B) was carried out by the university hospital pharmacy, resulting in four different combinations of the order of treatment condition and text.
|
|||||||||
|
Arms
|
||||||||||
Are arms mutually exclusive |
No
|
|||||||||
|
Arm title
|
Dopamine-condition | |||||||||
Arm description |
The study had a randomized, double-blind placebo-controlled within-subjects experimental design. A total of 80 participants were submitted to both experimental conditions (dopamine and placebo) at two separate lab sessions. | |||||||||
Arm type |
Experimental | |||||||||
Investigational medicinal product name |
SINEMET 125
|
|||||||||
Investigational medicinal product code |
RVG 08740
|
|||||||||
Other name |
||||||||||
Pharmaceutical forms |
Capsule
|
|||||||||
Routes of administration |
Oral use
|
|||||||||
Dosage and administration details |
At the beginning of the lab sessions, participants received capsules containing Sinemet125 and took the capsules orally.
|
|||||||||
|
Arm title
|
Placebo-condition | |||||||||
Arm description |
A total of 80 participants were submitted to both experimental conditions (dopamine and placebo) at two separate lab sessions. | |||||||||
Arm type |
Placebo | |||||||||
Investigational medicinal product name |
Placebo
|
|||||||||
Investigational medicinal product code |
||||||||||
Other name |
||||||||||
Pharmaceutical forms |
Capsule
|
|||||||||
Routes of administration |
Oral use
|
|||||||||
Dosage and administration details |
Lactose monohydrate with 1 % magnesium stearate (125mg)
|
|||||||||
|
||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Baseline characteristics reporting groups
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Reporting group title |
Experimental sessions
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Reporting group description |
80 students (mean age 21.38 years, SD = 1,84; 40 participants carrying the DRD4-7R allele, and 40 participants who did not) were selected to participate in the experimental sessions (both the dopamine and placebo condition). Students in the two groups (DRD4-7R+ and DRD4-7R-) did not differ in age, reading motivation, language skills, executive functioning in daily life, attentional control in daily life, or baseline reading speed. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Subject analysis sets
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subject analysis set title |
DRD4 7R+
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subject analysis set type |
Sub-group analysis | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subject analysis set description |
The final sample consisted of 40 students with the DRD4 7R+ genotype and 40 students with the DRD4 7R- genotype.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subject analysis set title |
DRD4 7R-
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subject analysis set type |
Sub-group analysis | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subject analysis set description |
The final sample consisted of 40 students with the DRD4 7R+ genotype and 40 students with the DRD4 7R- genotype.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||
|
End points reporting groups
|
|||
Reporting group title |
Dopamine-condition
|
||
Reporting group description |
The study had a randomized, double-blind placebo-controlled within-subjects experimental design. A total of 80 participants were submitted to both experimental conditions (dopamine and placebo) at two separate lab sessions. | ||
Reporting group title |
Placebo-condition
|
||
Reporting group description |
A total of 80 participants were submitted to both experimental conditions (dopamine and placebo) at two separate lab sessions. | ||
Subject analysis set title |
DRD4 7R+
|
||
Subject analysis set type |
Sub-group analysis | ||
Subject analysis set description |
The final sample consisted of 40 students with the DRD4 7R+ genotype and 40 students with the DRD4 7R- genotype.
|
||
Subject analysis set title |
DRD4 7R-
|
||
Subject analysis set type |
Sub-group analysis | ||
Subject analysis set description |
The final sample consisted of 40 students with the DRD4 7R+ genotype and 40 students with the DRD4 7R- genotype.
|
||
|
|||||||||||||
End point title |
Attentional control - average frontal TBR [1] | ||||||||||||
End point description |
|||||||||||||
End point type |
Primary
|
||||||||||||
End point timeframe |
during reading
|
||||||||||||
| Notes [1] - No statistical analyses have been specified for this primary end point. It is expected there is at least one statistical analysis for each primary end point. Justification: A repeated measures ANOVA with condition (dopamine vs. placebo) and type of attentional control measure (frontal TBR during reading, SD in frontal TBR during reading and self-reports of attentional control during reading) as within-subjects factors showed no main effect of condition (F(1,75) = 1.48, p = 0.23). Attentional control during reading did not differ between the levodopa condition and the placebo condition. |
|||||||||||||
|
|||||||||||||
| No statistical analyses for this end point | |||||||||||||
|
|||||||||||||
End point title |
Attentional control - SD in frontal TBR [2] | ||||||||||||
End point description |
|||||||||||||
End point type |
Primary
|
||||||||||||
End point timeframe |
during reading
|
||||||||||||
| Notes [2] - No statistical analyses have been specified for this primary end point. It is expected there is at least one statistical analysis for each primary end point. Justification: A repeated measures ANOVA with condition (dopamine vs. placebo) and type of attentional control measure (frontal TBR during reading, SD in frontal TBR during reading and self-reports of attentional control during reading) as within-subjects factors showed no main effect of condition (F(1,75) = 1.48, p = 0.23). Attentional control during reading did not differ between the levodopa condition and the placebo condition. |
|||||||||||||
|
|||||||||||||
| No statistical analyses for this end point | |||||||||||||
|
|||||||||||||
End point title |
Attentional control - self-reports [3] | ||||||||||||
End point description |
|||||||||||||
End point type |
Primary
|
||||||||||||
End point timeframe |
during reading
|
||||||||||||
| Notes [3] - No statistical analyses have been specified for this primary end point. It is expected there is at least one statistical analysis for each primary end point. Justification: A repeated measures ANOVA with condition (dopamine vs. placebo) and type of attentional control measure (frontal TBR during reading, SD in frontal TBR during reading and self-reports of attentional control during reading) as within-subjects factors showed no main effect of condition (F(1,75) = 1.48, p = 0.23). Attentional control during reading did not differ between the levodopa condition and the placebo condition. |
|||||||||||||
|
|||||||||||||
| No statistical analyses for this end point | |||||||||||||
|
|||||||||||||
End point title |
Summary task [4] | ||||||||||||
End point description |
|||||||||||||
End point type |
Primary
|
||||||||||||
End point timeframe |
post-test
|
||||||||||||
| Notes [4] - No statistical analyses have been specified for this primary end point. It is expected there is at least one statistical analysis for each primary end point. Justification: A repeated measures ANOVA was performed with condition (dopamine vs. placebo) and type of reading comprehension measure (summary task, text-level comprehension questions, spelling questions, open word meaning questions, and MC word meaning questions) as within-subjects factors. There was a significant main effect of condition on reading comprehension (F(1,79) = 11.55, p = 0.001). Participants performed worse on reading comprehension in the levodopa condition than in the placebo condition. |
|||||||||||||
|
|||||||||||||
| No statistical analyses for this end point | |||||||||||||
|
|||||||||||||
End point title |
Text-level comprehension questions [5] | ||||||||||||
End point description |
|||||||||||||
End point type |
Primary
|
||||||||||||
End point timeframe |
post-test
|
||||||||||||
| Notes [5] - No statistical analyses have been specified for this primary end point. It is expected there is at least one statistical analysis for each primary end point. Justification: A repeated measures ANOVA was performed with condition (dopamine vs. placebo) and type of reading comprehension measure (summary task, text-level comprehension questions, spelling questions, open word meaning questions, and MC word meaning questions) as within-subjects factors. There was a significant main effect of condition on reading comprehension (F(1,79) = 11.55, p = 0.001). Participants performed worse on reading comprehension in the levodopa condition than in the placebo condition. |
|||||||||||||
|
|||||||||||||
| No statistical analyses for this end point | |||||||||||||
|
|||||||||||||
End point title |
MC word meaning questions [6] | ||||||||||||
End point description |
|||||||||||||
End point type |
Primary
|
||||||||||||
End point timeframe |
post-test
|
||||||||||||
| Notes [6] - No statistical analyses have been specified for this primary end point. It is expected there is at least one statistical analysis for each primary end point. Justification: A repeated measures ANOVA was performed with condition (dopamine vs. placebo) and type of reading comprehension measure (summary task, text-level comprehension questions, spelling questions, open word meaning questions, and MC word meaning questions) as within-subjects factors. There was a significant main effect of condition on reading comprehension (F(1,79) = 11.55, p = 0.001). Participants performed worse on reading comprehension in the levodopa condition than in the placebo condition. |
|||||||||||||
|
|||||||||||||
| No statistical analyses for this end point | |||||||||||||
|
|||||||||||||
End point title |
Open word meaning questions [7] | ||||||||||||
End point description |
|||||||||||||
End point type |
Primary
|
||||||||||||
End point timeframe |
post-test
|
||||||||||||
| Notes [7] - No statistical analyses have been specified for this primary end point. It is expected there is at least one statistical analysis for each primary end point. Justification: A repeated measures ANOVA was performed with condition (dopamine vs. placebo) and type of reading comprehension measure (summary task, text-level comprehension questions, spelling questions, open word meaning questions, and MC word meaning questions) as within-subjects factors. There was a significant main effect of condition on reading comprehension (F(1,79) = 11.55, p = 0.001). Participants performed worse on reading comprehension in the levodopa condition than in the placebo condition. |
|||||||||||||
|
|||||||||||||
| No statistical analyses for this end point | |||||||||||||
|
|||||||||||||
End point title |
Spelling questions [8] | ||||||||||||
End point description |
|||||||||||||
End point type |
Primary
|
||||||||||||
End point timeframe |
post-test
|
||||||||||||
| Notes [8] - No statistical analyses have been specified for this primary end point. It is expected there is at least one statistical analysis for each primary end point. Justification: A repeated measures ANOVA was performed with condition (dopamine vs. placebo) and type of reading comprehension measure (summary task, text-level comprehension questions, spelling questions, open word meaning questions, and MC word meaning questions) as within-subjects factors. There was a significant main effect of condition on reading comprehension (F(1,79) = 11.55, p = 0.001). Participants performed worse on reading comprehension in the levodopa condition than in the placebo condition. |
|||||||||||||
|
|||||||||||||
| No statistical analyses for this end point | |||||||||||||
|
||||||||||||||||||||||
|
Adverse events information
|
||||||||||||||||||||||
Timeframe for reporting adverse events |
Experimental sessions
|
|||||||||||||||||||||
Adverse event reporting additional description |
None of the participants suffered from serious adverse events during or after our study related to the intake of Sinemet125 or the placebo treatment. Except for one participant reporting nausea in the placebo condition, no side effects of the medication were reported by the participants.
|
|||||||||||||||||||||
Assessment type |
Non-systematic | |||||||||||||||||||||
|
Dictionary used for adverse event reporting
|
||||||||||||||||||||||
Dictionary name |
N.A. | |||||||||||||||||||||
Dictionary version |
N.A.
|
|||||||||||||||||||||
|
Reporting groups
|
||||||||||||||||||||||
Reporting group title |
Dopamine condition
|
|||||||||||||||||||||
Reporting group description |
- | |||||||||||||||||||||
Reporting group title |
Placebo condition
|
|||||||||||||||||||||
Reporting group description |
- | |||||||||||||||||||||
|
||||||||||||||||||||||
| Frequency threshold for reporting non-serious adverse events: 1% | ||||||||||||||||||||||
|
||||||||||||||||||||||
|
|||
Substantial protocol amendments (globally) |
|||
| Were there any global substantial amendments to the protocol? No | |||
Interruptions (globally) |
|||
| Were there any global interruptions to the trial? No | |||
Limitations and caveats |
|||
| Limitations of the trial such as small numbers of subjects analysed or technical problems leading to unreliable data. | |||
| N.A. | |||
