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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]

None

Universal Trial Number (UTN)

U111111752153

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Attention Deficit/Hyperactivity Disorder

Condition category

Condition code

Mental Health

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]

Treatment: Drugs

Intervention code [2]

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]

Executive attention measured by a child-version of the Attention Network task (Fan et al., 2002).

Timepoint [1]

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]

Orienting (non-executive) attention measured by the child-version of the Attention Network Task (Fan et al., 2002).

Timepoint [1]

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]

Alerting (non-executive) attention measured by the child-version of the Attention Network Task (Fan et al. 2002)

Timepoint [2]

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

Sex

Both males and females

Can healthy volunteers participate?

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

15/02/2016

Actual

15/02/2016

Date of last participant enrolment

Anticipated

Actual

14/07/2017

Date of last data collection

Anticipated

Actual

20/08/2017

Sample size

Target

Accrual to date

Final

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Otago

Funding & Sponsors

Funding source category [1]

Charities/Societies/Foundations

Name [1]

Trygfonden

Address [1]

Hummeltoftevej 49
DK-2830 Virum

Country [1]

Denmark

Funding source category [2]

University

Name [2]

University of Copenhagen

Address [2]

Noedebovej 77 A
3480 Fredensborg
Denmark

Country [2]

Denmark

Primary sponsor type

University

Name

University of Copenhagen

Address

Noedebovej 77 A
3480 Fredensborg
Denmark

Country

Denmark

Secondary sponsor category [1]

University

Name [1]

University of Otago

Address [1]

362 Leith Street
North Dunedin
Dunedin 9016

Country [1]

New Zealand

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Health and Disabilities Ethics Committee (HDEC)

Ethics committee address [1]

Ministry of Health
Ethics Department
Reception - Ground Floor
20 Aitken Street
Thorndon
WELLINGTON

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

08/10/2015

Approval date [1]

11/11/2015

Ethics approval number [1]

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

Dr Dione Healey

Address

University of Otago
Department of Psychology
P.O. Box 56
Dunedin 9054

Country

New Zealand

Phone

+64 3 479 7620

Fax

dionehealey@psy.otago.ac.nz

Contact person for public queries

Name

Matt Stevenson

Address

Department of Geoscience and Natural Resource Management (Skovskolen)
University of Copenhagen
Noedebovej 77A
Fredensborg 3408

Country

Denmark

Phone

+45 93565277

Fax

mps@ign.ku.dk

Contact person for scientific queries

Name

Matt Stevenson

Address

Department of Geoscience and Natural Resource Management (Skovskolen)
University of Copenhagen
Noedebovej 77A
Fredensborg 3408

Country

Denmark

Phone

+45 93565277

Fax

mps@ign.ku.dk

No information has been provided regarding IPD availability

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No Supporting Document Provided

Results publications and other study-related documents

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