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Trial registered on ANZCTR


Registration number
ACTRN12616000125426
Ethics application status
Approved
Date submitted
27/11/2015
Date registered
3/02/2016
Date last updated
11/10/2017
Type of registration
Prospectively registered

Titles & IDs
Public title
A natural environment versus medication in children with ADHD.
Scientific title
Replacing a dose of medication with nature: Executive function performance in children
with ADHD after exposure to a natural environment.
Secondary ID [1] 288019 0
None
Universal Trial Number (UTN)
U111111752153
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Attention Deficit/Hyperactivity Disorder 296890 0
Condition category
Condition code
Mental Health 297118 297118 0 0
Other mental health disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
1. Stimulant medication - methylphenidate, 5mg, oral tablet, taken daily, dose and adherence supervised by registered psychiatrist from the Department of Medicine, University of Otago. Overencapsulated in size 0 opaque gelatin capsules. Control = placebo made from 4 grains of Orzo pasta encapsulated in size 0 opaque gelatin capsules.
2. Walk in a natural environment - 30 minutes, once daily, adherence supervised by two research assistants. Control = Walk in a built environment.
3. Each participant will recieve a total of four combinations of the two interventions and their controls, described above. Namely, 1) methylphenidate + walk in natural environment; 2) methylphenidate + walk in built environment (Control) ; 3) placebo (Control) + walk in natural environment; 4) placebo (Control) + walk in built environment (Control)
4. Wash out period: 7 days
- Duration for each of the four arms: 7 days per condition.
Intervention code [1] 293346 0
Treatment: Drugs
Intervention code [2] 293347 0
Lifestyle
Comparator / control treatment
1. Control for methylphenidate intervention (Arm One) = 4 grains of Orzo pasta encapsulated in size 0 opaque gelatin capsules.

2. Control for walk in natural environment (Arm Two) = Walk in a built environment (quiet neighbourhood
Control group
Placebo

Outcomes
Primary outcome [1] 296738 0
Executive attention measured by a child-version of the Attention Network task (Fan et al., 2002).
Timepoint [1] 296738 0
Immediately prior to- and immediately following intervention (pre-test, post-test). Post-test assessment will take place approximately one hour after administration of the stimulant or placebo.
Secondary outcome [1] 319217 0
Orienting (non-executive) attention measured by the child-version of the Attention Network Task (Fan et al., 2002).
Timepoint [1] 319217 0
Immediately prior to- and immediately following intervention (pre-test, post-test). Post-test assessment will take place approximately one hour after administration of the stimulant or placebo.
Secondary outcome [2] 320081 0
Alerting (non-executive) attention measured by the child-version of the Attention Network Task (Fan et al. 2002)
Timepoint [2] 320081 0
Immediately prior to- and immediately following intervention (pre-test, post-test). Post-test assessment will take place approximately one hour after administration of the stimulant or placebo.

Eligibility
Key inclusion criteria
Participants must have a current diagnosis of Attention Deficit/Hyperactivity Disorder
Minimum age
6 Years
Maximum age
16 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Participants must not have a sub-diagnosis of ADHD-predominantly hyperactive subtype. Further, participants must not have any co-morbid diagnoses of cognitive impairment.,

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using computer software, obtained by the psychiatrist associated with the study.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other
Other design features
Participants will be blinded to medication type (stimulant medication vs. placebo), however environment (natural vs. built) can not be blinded.

Each participant will recieve a total of four combinations of the two interventions and their controls, described above. Namely, 1) methylphenidate + walk in natural environment; 2) methylphenidate + walk in built environment (Control) ; 3) placebo (Control) + walk in natural environment; 4) placebo (Control) + walk in built environment (Control). Thus, each participant acts as their own control. The order in which participants recieve the intervention combinations will be randomised by computer.
Phase
Phase 2
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Differences (after walk minus before walk) will be analysed with a linear mixed model with fixed effects of medication-type, environment, session, order of environment, age, gender, and random effect of child. The treatment factor has a 2 x 2 structure (combination of environment and medication). The main effects of environment and medication as well as their interaction are of primary interest, whereas the other variables are included in order to reduce residual variability.
The proposed study is quite unique, however, power calculations were completed by a professor of applied statistics from the Department of Mathematics at the University of Copenhagen for a related study investigating performance on the Attention Network Task after a walk in a natural environment. Previous studies suggest a decrease of 20 in RT scores for the Executive Attention component after exposure to a natural environment, with no change after exposure to a built environment. With these values, 40 children are required to get a power of 90% (when the test is carried out with significance level 5%). The current study will allow for more accurate measures for childrens performance in such conditions.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment outside Australia
Country [1] 7380 0
New Zealand
State/province [1] 7380 0
Otago

Funding & Sponsors
Funding source category [1] 292469 0
Charities/Societies/Foundations
Name [1] 292469 0
Trygfonden
Address [1] 292469 0
Hummeltoftevej 49
DK-2830 Virum

Country [1] 292469 0
Denmark
Funding source category [2] 292470 0
University
Name [2] 292470 0
University of Copenhagen
Address [2] 292470 0
Noedebovej 77 A
3480 Fredensborg
Denmark
Country [2] 292470 0
Denmark
Primary sponsor type
University
Name
University of Copenhagen
Address
Noedebovej 77 A
3480 Fredensborg
Denmark
Country
Denmark
Secondary sponsor category [1] 291169 0
University
Name [1] 291169 0
University of Otago
Address [1] 291169 0
362 Leith Street
North Dunedin
Dunedin 9016
Country [1] 291169 0
New Zealand

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 293934 0
Health and Disabilities Ethics Committee (HDEC)
Ethics committee address [1] 293934 0
Ministry of Health
Ethics Department
Reception - Ground Floor
20 Aitken Street
Thorndon
WELLINGTON
Ethics committee country [1] 293934 0
New Zealand
Date submitted for ethics approval [1] 293934 0
08/10/2015
Approval date [1] 293934 0
11/11/2015
Ethics approval number [1] 293934 0
15/NTB/206

Summary
Brief summary
Past research has shown that performance on executive function tasks can be improved after a walk in a natural environment. This has been found across a number of participant groups, including children with ADHD. Taylor and Kuo (2009) reported improvements in working memory in children with ADHD with a statistical effect size that was comparable to those seen with two formulations of pharmacological treatment (methylphenidate). We aim to investigate whether natural environments can improve executive function performance in children with ADHD, and whether this is affected by medication status. Specifically, we ask whether performance after walking in a natural environment and taking a placebo is better than performance after walking in a built environment and taking a dose of psychostimulant medication. Further, we ask whether exposure to a natural environment can enhance the effect of psychostimulant medication to improve executive function performance. We aim to provide evidence for the suggestion that such an intervention may be pursued as a supplementary strategy for managing the disorder. We extend the current research by including medication status as a withinsubject
factor to answer the questions: 1) Do the treatment combinations of "natural
environment + placebo" and "built environment + psychostimulant medication" both improve cognitive performance in children with ADHD? and 2) Does the treatment combination of "natural environment + psychostimulant medication" improve cognitive performance to a higher degree than either treatment alone? Based on previous studies, we predict both treatment combinations ("natural environment + placebo" and "built
environment + medication") will improve cognitive performance (executive attention score) in children with ADHD. Further, we predict that the treatment combination of "natural environment + medication" will be associated with greater a cognitive improvement (executive attention score) than the other three treatment combinations (natural environment + placebo, built environment + medication, and built environment + placebo).
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 61850 0
Dr Dione Healey
Address 61850 0
University of Otago
Department of Psychology
P.O. Box 56
Dunedin 9054
Country 61850 0
New Zealand
Phone 61850 0
+64 3 479 7620
Fax 61850 0
Email 61850 0
dionehealey@psy.otago.ac.nz
Contact person for public queries
Name 61851 0
Mr Matt Stevenson
Address 61851 0
Department of Geoscience and Natural Resource Management (Skovskolen)
University of Copenhagen
Noedebovej 77A
Fredensborg 3408
Country 61851 0
Denmark
Phone 61851 0
+45 93565277
Fax 61851 0
Email 61851 0
mps@ign.ku.dk
Contact person for scientific queries
Name 61852 0
Mr Matt Stevenson
Address 61852 0
Department of Geoscience and Natural Resource Management (Skovskolen)
University of Copenhagen
Noedebovej 77A
Fredensborg 3408
Country 61852 0
Denmark
Phone 61852 0
+45 93565277
Fax 61852 0
Email 61852 0
mps@ign.ku.dk

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary