CANreduce 2.0 - comparing two differently optimized versions of a web-based self-help program to reduce cannabis use with each other and a waiting list

• Register: ISRCTN
• Last refreshed on: 2 May 2022
• Main ID: ISRCTN11086185
• Date of registration: 18/08/2016
• Prospective Registration: No
• Primary sponsor: Research Institute for Public Health and Addiction (ISGF)
• Public title: CANreduce 2.0 - comparing two differently optimized versions of a web-based self-help program to reduce cannabis use with each other and a waiting list
• Scientific title: CANreduce 2.0 - the effects of an adherence-focused guidance enhanced web-based self-help program, an unenhanced web-based self-help program and a waiting list control on cannabis use in problematic cannabis users: a randomized controlled trial
• Date of first enrolment: 02/08/2016
• Target sample size: 597
• Recruitment status: Completed
• URL: https://www.isrctn.com/ISRCTN11086185
• Study type: Interventional
• Study design: Randomised controlled trial (Treatment)
• Phase: Not Applicable

Countries of recruitment

Austria, Germany, Switzerland

Contacts

• Name: Manuel Amann

Key inclusion & exclusion criteria

Inclusion criteria:
1. Cannabis use of at least once a week 30 days prior to study entry
2. At least 18 years old
3. At least weekly internet access and a valid email address

Exclusion criteria:
1. Current pharmacological psychiatric disease or history of psychosis, schizophrenia, bipolar type I disorder or significant current suicidal or homicidal thoughts
2. Use of other pharmacological and psycho-social treatments for cannabis use disorders
3. Inability to read or write in German


Age minimum:
Age maximum:
Gender: Both

Health Condition(s) or Problem(s) studied

Problematic cannabis use
Mental and Behavioural Disorders

Intervention(s)

Participants are randomly allocated to one of three arms:
1. Intervention group: Adherence-focused guidance enhanced web-based self-help program
2. Active control group: Unenhanced web-based self-help program
3. Waiting control group: Waiting list

CANreduce is an automated web-based self-help tool based on classical CBT approaches for treating cannabis dependence. It will consist of a consumption diary, eight modules designed to reduce cannabis use based on the principles of motivational interviewing, self-control practices, and methods of cognitive behavioural therapy ( strategies for goal achievement, Identifying risk situations, Dealing with cannabis craving, Dealing with relapses, Working on needs, Saying “no” to foster refusal skills, Dealing with burdens, Preserving achievements). Participants can study all modules at their own pace and order, though a specific order will be advised.

The control condition is a waiting list. After 3 months their study phase is finished and they will be given the opportunity to start the self-help program. Furthermore, there will be an active control group which works with the unenhanced version of the self-help tool.

The masking technique will be single-blind, i.e. participants will not know if they work with the enhanced or unenhanced version (however, they will know if they have been assigned to the waiting list).

Once participants have completed their baseline assessment, they will be randomized by a computer program in a 1:1:1 ratio to 1 of 3 “parallel” groups, and this assignment will be automatically registered in the background database. As participants will see if they have been assigned to th

Primary Outcome(s)

Quantity and the number of days per week of cannabis use. Participants enter their cannabis consumption quantity and frequency into their consumption diary every week.

Timepoints of measures will be initial assessment, after 6 weeks and at 3 months follow-up.

Secondary Outcome(s)

1. Severity of cannabis dependence (SDS)
2. The use of alcohol, tobacco, and other non-cannabis illicit drugs (FDA)
3. Changes in depression, anxiety and attention deficit symptoms (CES-D, GAD-7 and ASRS-V1.1)
4. Post traumatic Stress Disorder (Short Screening Scale for DSM-IV)
5. Client satisfaction (ZUF-8)

Severity of cannabis dependence and the use of alcohol, tobacco, and other non-cannabis illicit drugs will be measured at initial assessment, after 6 weeks and at 3 months follow-up.

Changes in depression, anxiety, attention deficit symptoms and the Short Screening Scale for DSM-IV Post traumatic Stress Disorder will be measured at initial assessment and at 3 months follow-up.

Client satisfaction will be measured after 6 weeks.

Secondary ID(s)

2016-00264

Source(s) of Monetary Support

Research Institute for Public Health and Addiction (ISGF)

Ethics review

Status:
Approval date:
Contact:

Kantonale Ethikkommission Zürich (Ethics board of the canton Zurich), 04/07/2016, ref: BASEC-Nr. 2016-00264

Results

• Results available: Yes
• Date Completed: 01/12/2017