ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12617001544369

Ethics application status

Approved

Date submitted

27/10/2017

Date registered

7/11/2017

Date last updated

11/10/2018

Type of registration

Prospectively registered

Titles & IDs

Public title

Pharmaceutical enhancement of complex problem-solving in healthy adults

Scientific title

Effect of pharmaceutical dopaminergic enhancement on performance in a complex optimisation task in healthy adults

Secondary ID [1]

CT-2017-CTN-04278-1 (Therapeutic Goods Administration, Australia)

Universal Trial Number (UTN)

U1111-1204-3404

Trial acronym

PECO

Linked study record

Health condition

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

Cognitive enhancement

Condition category

Condition code

Mental Health

Studies of normal psychology, cognitive function and behaviour

Neurological

Studies of the normal brain and nervous system

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

A single oral dose of a capsule containing 15 milligrams dextroamphetamine, 30 milligrams of methylphenidate, 200 milligrams of modafinil or placebo prior to cognitive testing in a repeated-measures full crossover double-blinded design in healthy volunteers. A washout period of at least seven days will be observed between testing sessions. Cognitive testing commences 90 minutes after dosage, and includes solving complex optimisation problems, spatial working memory tests, motor inhibition tests, reaction time and spatial problem solving. Cognitive testing will take between 60 and 90 minutes, depending on the speed of the individual participant.

Intervention code [1]

Treatment: Drugs

Comparator / control treatment

This is a placebo-controlled, double-blinded full-crossover repeated-measures design. Placebo will be microcellulose (Avicel) capsule.

Control group

Placebo

Outcomes

Primary outcome [1]

Performance in complex optimisation task as measured by accuracy scores. That is, are the items selected by the participant included in the optimal solution. This is also referred to as "computational perfomance".

Timepoint [1]

Tasks will be administered 90 minutes after drug administration, and completed by 180 minutes after drug administration. This outcome will be assessed for each drug administration.

Secondary outcome [1]

Network analysis of the steps taken to solve the complex optimisation tasks. That is, analysis of which items are selected and deselected as the participant attempts to maximise ("optimise") the solution to the problem. This sequence of selection and deselection of items can be visualised in "decision space" and the number of steps taken to achieve a solution can be analysed.

Timepoint [1]

Tasks will be administered 90 minutes after drug administration, and completed by 180 minutes after drug administration. This outcome will be assessed for each drug administration.

Secondary outcome [2]

"Economic performance" of the complex optimisation task, that is, how close the submitted solution is to the known optimal solution.

Timepoint [2]

Tasks will be administered 90 minutes after drug administration, and completed by 180 minutes after drug administration. This outcome will be assessed for each drug administration.

Secondary outcome [3]

Spatial working memory performance, as measured by error rate on the CANTAB spatial working memory task.

Timepoint [3]

Tasks will be administered 90 minutes after drug administration, and completed by 180 minutes after drug administration. This outcome will be assessed for each drug administration.

Secondary outcome [4]

Motor inhibition, as measured by error rate on the CANTAB stop-signal task.

Timepoint [4]

Tasks will be administered 90 minutes after drug administration, and completed by 180 minutes after drug administration. This outcome will be assessed for each drug administration.

Secondary outcome [5]

Reaction time, as measured on the CANTAB reaction time task.

Timepoint [5]

Tasks will be administered 90 minutes after drug administration, and completed by 180 minutes after drug administration. This outcome will be assessed for each drug administration.

Secondary outcome [6]

Spatial problem solving, as measured by accuracy rate on the CANTAB stockings of Cambridge task.

Timepoint [6]

Tasks will be administered 90 minutes after drug administration, and completed by 180 minutes after drug administration. This outcome will be assessed for each drug administration.

Eligibility

Key inclusion criteria

Healthy volunteers aged between 18 and 35 years old.

Minimum age

18 Years

Maximum age

35 Years

Sex

Both males and females

Can healthy volunteers participate?

Yes

Key exclusion criteria

History of psychiatric or neurological illness including epilepsy, head injury, previous use of psychotropic medication, history of significant drug use, heart conditions (including high blood pressure, defined as above 140 mm/Hg systolic and/or 90 mm/Hg diastolic pressure as measured at the initial assessment session) pregnancy, or glaucoma. Any family history of sudden death of a first degree relative through cardiac or unknown causes before the age of 50 years old will also exclude the participant.

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)

Sealed opaque envelopes

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Simple randomisation using a randomisation table created by
computer software.

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

Crossover

Other design features

Phase

Phase 4

Type of endpoint/s

Efficacy

Statistical methods / analysis

Power calculations performed with G*Power found that for a repeated-measures within-factors ANOVA with one group and four measurements, an estimated within-participants correlation of 0.5 and an eta squared of 0.2 (equivalent effect size 0.5) the calculated total minimum sample size is 10 and the critical F score is 2.69. For a within-between interaction, the minimum sample size would be 12, and critical F score 2.92. If the correlation is changed to 0.1 the total minimum sample size is 17, and the critical F score is 2.798. For a within-between interaction, the minimum sample size would be 18, and critical F score 2.798. When the alpha error probability is reduced from 0.05 to 0.0167 to allow for the repeated
comparisons between the three medication conditions and placebo, the corresponding total sample sizes are 13, 14, 21 and 22 participants. This project proposes a total sample size of 32 participants.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

24/11/2017

Actual

24/11/2017

Date of last participant enrolment

Anticipated

31/01/2018

Actual

30/07/2018

Date of last data collection

Anticipated

30/04/2018

Actual

14/09/2018

Sample size

Target

32

Accrual to date

Final

42

Recruitment in Australia

Recruitment state(s)

VIC

Funding & Sponsors

Funding source category [1]

University

Name [1]

The University of Melbourne

Address [1]

The University of Melbourne
Victoria 3010

Country [1]

Australia

Primary sponsor type

University

Name

The University of Melbourne

Address

The University of Melbourne
Victoria 3010

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

University of Melbourne Health Sciences Human Ethics Sub-Committee

Ethics committee address [1]

Research Ethics & Integrity
Level 1, 21 Bedford St, North Melbourne
The University of Melbourne
VIC 3051

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

15/08/2017

Approval date [1]

22/09/2017

Ethics approval number [1]

1749142

Summary

Brief summary

A) Aims and Objectives
This project aims to investigate the role of the neurotransmitter dopamine in complex decision making, and how three prescription stimulant medications that modulate dopamine levels in the brain in slightly different ways can affect the quality of complex decision making. These medications (dextroamphetamine, methylphenidate and modafinil) are increasingly used by healthy people for non-medical, cognitive enhancement purposes, however their effects on basic cognition are often found to be inconsistent, and their effects on more naturalistic, complex optimisation behaviours are not known.
B) Key Question(s)
Do stimulant medications, that increase dopamine in the brain, enhance, or have a deleterious effect, on the completion of a complex decision making task. More specifically do they;
* Affect the amount of time taken to solve a problem? 
* Increase or decrease the likelihood that a participant will find the correct solution to the problem (the computational performance)?
* Increase or decrease the computational distance between the participant’s solution and the correct solution (the economic performance)?
* Affect the variety of search paths that participants take through the space of possible solutions?

C) Research Design
This study will utilize a double-blinded placebo-controlled crossover design. We will recruit 32 healthy participants with no history of neurological, psychiatric or heart conditions. Each one will participate in an initial assessment session and four testing sessions, each at least one week apart to allow for pharmaceutical washout. At each session, the participant will receive either a single dose of the three pharmaceuticals or the placebo. After a 90-minute waiting period, during which the participant fills out number of demographic and personality surveys, the participant will complete a series of computerised complex optimisation tasks and basic cognition tasks. Data collected includes the sequence and timing of the selection of items for each task solution, key variables from the more basic cognitive tasks and the answers to the survey questions.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Prof David Coghill

Address

Departments of Paediatrics and Psychiatry
The University of Melbourne
Professor of Child and Adolescent Psychiatry,
The Royal Children’s Hospital,
50 Flemington Road,
Parkville, Victoria, 3052

Country

Australia

Phone

+61 3 9345 6856

Fax

Email

david.coghill@unimelb.edu.au

Contact person for public queries

Name

Elizabeth Bowman

Address

Brain, Mind and Markets Laboratory
Department of Finance
The University of Melbourne
Victoria, 3010

Country

Australia

Phone

+61 3 9035 9950

Fax

+61 3 8344 6914

Email

eabowman@unimelb.edu.au

Contact person for scientific queries

Name

Elizabeth Bowman

Address

Brain, Mind and Markets Laboratory
Department of Finance
The University of Melbourne
Victoria, 3010

Country

Australia

Phone

+61 3 9035 9950

Fax

+61 3 8344 6914

Email

eabowman@unimelb.edu.au

No information has been provided regarding IPD availability

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

No additional documents have been identified.