Condition category
Mental and Behavioural Disorders
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Cannabis use increases the problems that people with severe mental health problems face. For example, young people with psychosis who use cannabis are more likely than those who do not to have difficulty recovering from their initial symptoms of psychosis, to relapse once they have recovered, to commit crimes, and less likely to work. Their need to rely on welfare benefits and frequent use of expensive services such as hospital has implications for society as a whole. Early intervention services (EISs) are a type of mental health team now available throughout England, They aim to improve prognosis for young people with early psychosis, reducing the likelihood that they will relapse and helping them achieve their goals, which may include getting back to work or education. Almost half the young people on EIS caseloads use cannabis, so that it is an important obstacle to recovery. Many young people who have developed a psychotic illness have some motivation for reducing their cannabis use. However, we do not have a really effective treatment available for helping them to do so. It has proved difficult to design treatments that work for drug use among people who have psychotic illnesses. Our aim is to try out a new approach called Contingency Management that is increasingly used in drug services but has not been studied a lot among people with psychosis.

Who can participate?
The participants in our study will be people aged between 18 and 39 who are currently under the care of an early intervention service for psychosis, and who have used cannabis in the past 6 months. They will be men and women.

What does the study involve?
The study will compare two approaches to helping people reduce their cannabis use. Group A will receive both a new approach called Contingency Management and a short educational package. Contingency Management involves receiving voucher rewards, to be spent in local shops, on condition of attending appointments and providing urine samples free from cannabis. Rewards increase with increasing weeks of abstinence over a 3 month period. The educational package is intended to help people to decide whether or not they wish to carry on using cannabis. Group B will receive the educational package only.
We will then compare Group A and Group B, assessing over an 18 month period which group is more likely to relapse, to use cannabis, to have more severe symptoms of psychosis, and to be in work or education.

What are the possible benefits and risks of participating?
The main benefit to participants will be if the study treatments, especially that received by Group A, turns out to help people to reduce their cannabis use. This may have significant benefits for their health and progress towards their goals in life. The participants in Group A will also benefit from receiving voucher rewards if they can avoid using cannabis. There are few significant risks: the vouchers will not be exchangeable for alcohol, but it is possible that some participants may find ways of informally trading them for money to purchase substances.

Where is the study run from?
The lead centre is the Mental Health Sciences Unit at University College London. There will be n initial study in three London Boroughs – Camden, Islington and Hackney – and in Coventry and Warwickshire NHS Foundation Trust, linked to the University of Warwick. If this goes well, we will add further teams to a full-scale study, based around UCL, the University of Warwick, the University of East Anglia and King’s College London.

When is the study starting and how long is it expected to run for?
We expect the study to start in January 2012. Over the first 18 months, we will carry out an initial study to test whether we can recruit participants and whether the study treatments are acceptable to patients and staff. If it goes well, more centres will be added to make it a full study. The total study period will be four and a half years, ending in July 2016.

Who is funding the study?
The study is funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme

Who is the main contact?
Prof. Sonia Johnson

Trial website

Contact information



Primary contact

Prof Sonia Johnson


Contact details

Mental Health Sciences Unit
University College London
Charles Bell House
67-73 Riding House Street
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number

HTA 09/144/50

Study information

Scientific title

Randomised controlled trial of the clinical and cost-effectiveness of a contingency management intervention for reduction of cannabis use and of relapse in early psychosis



Study hypothesis

Time to relapse will be significantly greater in a group of early intervention service users who receive psychoeducation combined with contingency management (voucher rewards for evidence of abstinence) than in a group who receive the psychoeducation only.

More details can be found at:
Protocol can be found at:

Ethics approval

Not provided at time of registration

Study design

Feasibility pilot individually randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

GP practices

Trial type

Quality of life

Patient information sheet

See additional files


Psychotic illnesses including schizophrenia, schizo-affective disorder and bipolar disorder with psychotic symptoms


Experimental group: Contingency management involving voucher rewards for abstinence demonstrated by urinalysis together with psychoeducation delivered by care coordinators.

Control group: Psychoeducation only

Intervention type



Not Applicable

Drug names

Primary outcome measure

Time to relapse is assessed as admission to acute mental health care over 18 months

Secondary outcome measures

1. Presence of cannabis on urinalysis at 3 months and at 18 months of follow up
2. Positive symptom severity measured by Positive and Negative Syndrome Scale (PANSS) at 3 months and 18 months
3. Engagement in work or study is assessed by participant self report at 3 months and 18 months

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Under the care of an early intervention service for psychosis
2. Diagnostic criteria for EIS entry require a first psychotic episode significantly impairing functioning and lasting more than a week
3. Problematic cannabis use is operationalised as having used cannabis at least once in at least 12 of the previous 24 weeks
4. Aged 18-39, male and female participants

Participant type


Age group




Target number of participants

544 including 68 participants in feasibility pilot study

Total final enrolment


Participant exclusion criteria

Insufficient English to complete the study assessments

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

University College London
United Kingdom

Sponsor information


University College London (UK)

Sponsor details

c/o Dr Nick McNally
Director of Research Support
Joint University College London Hospitals/ University College London/ Royal Free Hospital Biomedical Research Unit
25 Grafton Way
United Kingdom

Sponsor type




Funder type


Funder name

Health Technology Assessment Programme

Alternative name(s)

NIHR Health Technology Assessment Programme, HTA

Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

Planned publication of study results in a peer reviewed journal. Submission of a report to funders in November 2017.

IPD Sharing plan:
The current data sharing plans for the current study are unknown and will be made available at a later date.

Intention to publish date


Participant level data

To be made available at a later date

Basic results (scientific)

Publication list

2016 protocol in:
2019 results in: (added 16/08/2019)
2019 report in: (added 29/08/2019)

Publication citations

Additional files

Editorial Notes

29/08/2019: Publication reference added. 16/08/2019: Publication reference and total final enrolment number added. 05/01/2017: The methods of measurement have been added to the secondary outcome measures. In addition, the participant information sheet, participant level data availability and publication and dissemination plan have been added. 04/01/2017: The overall trial dates have been updated from 01/01/2011 - 30/06/2016 to 01/09/2010 - 31/10/2017 and the recruitment dates have been updated from 01/01/2011 - 30/06/2016 to 01/06/2012 - 31/03/2016. 25/10/2016: Publication reference added.