Condition category
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Contact information



Primary contact

Prof Ronan O'Carroll


Contact details

University of Stirling
Division of Psychology
School of Natural Sciences
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

A randomised controlled trial of a brief psychological intervention to increase the uptake of colorectal cancer screening in adults aged 50-74 years in Scotland



Study hypothesis

In this large-scale, questionnaire-based study we will test whether asking people whether they would later regret not returning their Faecal Occult Blood Test (FOBT) screening kit for colorectal cancer increases FOBT returns.

Research questions:
1. Does a brief, theory-based anticipated regret (AR) intervention lead to a significant increase in the uptake of FOBT colorectal cancer screening in Scotland?
2. Is the effect observed equally across genders and social deprivation levels?
3. Is the effect a general consequence of the 'mere measurement effect' (i.e. completing a questionnaire about the topic in question may increase response) or is it a specific consequence of AR?
4. Is uptake influenced by participants' health beliefs, in particular anticipated regret, disgust, intention, perceived benefit and health locus of control?

Ethics approval

Not provided at time of registration

Study design

Three-armed prospective randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Colorectal bowel cancer screening


We will adopt a simple, between-groups, three-arm prospective randomised controlled trial design:
1. Control: no questionnaire
2. HLOC: Health Locus of Control questionnaire
3. AR: Anticipated regret questionnaire
Participants who are allocated to the questionnaire arms (2 & 3) will be told that we are studying the effects of attitudes towards screening, and how they influence FOBT returns.

Control arm
Participants in the control arm will be sent the standard pre-notification letter, according to current practice.

HLOC Intervention
Those randomly allocated to the HLOC group will also be sent the pre-notification letter plus the 18-item Health Locus of Control scale. HLOC participants will also be asked to rate their perceived disgust (ick factor) and perceived benefit of returning their FOBT using modified versions of the ick-factor scale and perceived benefit scales from our previous research with organ donation, as well as rating their intention of returning the FOBT test, all using simple scales. Participants will be asked to return this brief questionnaire in a stamped addressed envelope that will be provided. We predict that high scores on chance HLOC will predict lower return rates, as this taps a fatalistic view of health and health outcomes.

AR Intervention
Those allocated to the AR group will also be sent the pre-notification letter and will be asked to complete the same HLOC/ick/perceived benefit questionnaire as the HLOC group with 2 additional AR questions. The first of these additional questions will be placed as the very first question of the survey ('If I did not complete and return my test kit I would later feel regret') and the second will be placed immediately preceding the final question measuring intention to return the kit ('If I did not complete and return my test kit, I would later wish I had'). In order to make the two questionnaires identical in length, the HLOC questionnaire will have 2 filler questions added in the same location as the AR questions.

Intervention type



Not Applicable

Drug names

Primary outcome measures

Return of the completed FOBT test kit to the central laboratory at the Scottish Bowel Screening Centre, within 6 months of the kit being sent out.

Secondary outcome measures

1. Health Locus of Control Scale
2. Perceived disgust (ick factor)
3. Perceived benefit of returning the FOBT kit
4. Intention to return the FOBT test

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Members of the Scottish general public who are invited to participate in the national colorectal cancer screening programme
2. Aged between 50 and 74 years

Participant type


Age group




Target number of participants

60,000 individuals, randomised to 3 arms (20,000 in each arm)

Participant exclusion criteria

Does not meet inclusion criteria

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

University of Stirling
United Kingdom

Sponsor information


University of Stirling (UK)

Sponsor details

c/o Carol Johnstone
Research and Enterprise Office
United Kingdom

Sponsor type




Funder type


Funder name

Chief Scientist Office of the Scottish Executive Health Department (UK) ref: CZH/4/793

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

2013 protocol in:
2015 results in:

Publication citations

  1. Protocol

    O'Carroll RE, Steele RJ, Libby G, Brownlee L, Chambers JA, Anticipated regret to increase uptake of colorectal cancer screening in Scotland (ARTICS): study protocol for a randomised controlled trial., BMC Public Health, 2013, 13, 849, doi: 10.1186/1471-2458-13-849.

  2. Results

    O'Carroll RE, Chambers JA, Brownlee L, Libby G, Steele RJ, Anticipated regret to increase uptake of colorectal cancer screening (ARTICS): A randomised controlled trial, Soc Sci Med, 2015 , 142, 118-127, doi: 10.1016/j.socscimed.2015.07.026.

Additional files

Editorial Notes