Condition category
Mental and Behavioural Disorders
Date applied
15/04/2013
Date assigned
23/04/2013
Last edited
16/10/2015
Prospective/Retrospective
Prospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Cannabis is the most widely used illegal drug in Switzerland, other Western European countries, Australia and the USA. Most users consume cannabis for recreational purposes, only from time to time or on special occasions. However, some users smoke cannabis more frequently and in higher quantities. These users risk adverse physical and mental health effects. Moreover, there is a certain risk of addiction that can have various psycho-social consequences (like e.g. problems with partner, parents, at work etc.)
in Switzerland and its neighboring countries, treatment for cannabis use disorders like cannabis dependence is mainly provided by outpatient addiction treatment services. For many users these services are difficult to access. Some users also hesitate to get into face-to-face contact as they worry that this could have negative consequences such as stigmatization. In order to improve anonymous treatment and to provide free access to treatment access we have developed the Cannabis Control program.

Who can participate?
Cannabis users aged 18 and above, either sex, and who have smoked cannabis at least once per week in the past 30 days prior to enrolment in the study.

What does the study involve?
Participants will be randomly allocated to one of three groups:
Group 1: Participants will have three individual chat-counseling sessions based on motivational interviewing and cognitive-behavioral therapy approaches in combination with the web-based self-help intervention from Group 2.
Group 2: The web-based self-help intervention is based on classical cognitive behavioral therapy approaches for cannabis addiction, motivational interviewing approaches, and principles of self control.
Group 3: Classical waiting list.
For Group 1 and Group 2, there will be weekly reminder emails to login and fill out a consumption diary. Counseling sessions in Group 1 are provided by trained addiction counselors. Moreover, 8 specific modules to work through in a fixed order but time independent manner will be offered to Group 1 and Group 2. Participants allocated to Group 3 will have the opportunity to participate in the web-based self-help intervention after the follow-up assessment. Follow-up measures will be assessed online and/or by telephone calls three months after enrolment.

What are the possible benefits and risks of participating?
Within the 6 week web-based Cannabis Control program, participants can learn to reduce and control their cannabis use.
Cannabis abstinence or possibly also strong reduction of the frequency and quantity of cannabis may cause withdrawal symptoms or adverse events. In case of serious withdrawal symptoms or adverse events, additional telephone contacts to professionals are provided. Additional costs resulting from these personal contacts are to be covered by the general health insurance that is compulsory for everybody in Switzerland.

Where is the study run from?
The Cannabis Control study has been set up by the Swiss Research Institute for Public Health and Addiction, a World Health Organization Collaborating Center for Substance Abuse, associated institute to Zurich University, Switzerland. The study will be conducted in close collaboration with ARUD, the leading outpatient addiction counseling organization in the Canton of Zurich, Switzerland.

When is the study starting and how long is it expected to run for?
Recruitment in expected to start mid-2013. Participants will be enrolled for a period of two years.

Who is funding the study?
The Swiss Office for the Coordination of Addiction Facilities – infodrog (Switzerland).

Who is the main contact?
Dr Michael Schaub
michael.schaub@isgf.uzh.ch

Trial website

Contact information

Type

Scientific

Primary contact

Dr Michael Schaub

ORCID ID

Contact details

Swiss Research Institute for Public Health and Addiction (ISGF)
Konradstrasse 32
Postfach
Zurich
8031
Switzerland

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

N/A

Study information

Scientific title

Chat-Counseling and Web-Based Self-Help versus Web-Based Self-Help Intervention versus Waiting List to Control Cannabis Use in Problematic Cannabis Users: A Randomized Controlled Trial

Acronym

Cannabis Control

Study hypothesis

It is hypothesized, that web-based interventions which are more interactive are more effective in reducing cannabis use in problematic cannabis users. Therefore we will test the following detailed study hypotheses:
1. Chat-based counseling in combination with web-based self-help for the reduction of cannabis use is more effective than the waiting list control condition.
2. Web-based self-help for the reduction of cannabis use is more effective than the waiting list control condition.
3. Chat-based counseling in addition to web-based self-help for the reduction of cannabis use is more effective than web-based self-help alone.

Ethics approval

Ethics Committee of the Canton of Zurich, Switzerland, 11th April 2013, ref: KEK-StV-Nr. 15/13.

Study design

Three arm randomized controlled web-based trial

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Other

Trial type

Treatment

Patient information sheet

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

Condition

Cannabis misuse and cannabis abuse

Intervention

This is a three arm randomized controlled trial. The intervention in the first arm consists of three individual chat-counseling sessions based on motivational interviewing and cognitive-behavioral therapy approaches in combination with the web-based self-help intervention from study arm two. The web-based self-help intervention from study arm two is based on classical cognitive behavioral therapy approaches for cannabis addiction, motivational interviewing approaches, and principles of self control. The third study arm consists of a classical waiting list.

Study arms 1-2 involve weekly reminder e-Mails to login and fill out a consumption diary. Counseling sessions in study arm one are provided by trained addiction counselors. Moreover, 8 specific modules to work through in a fixed order but time independent manner will be offered in study arms 1-2. Participants randomized to the waiting list will have the opportunity to participate in the web-based self-help intervention after the follow-up assessment. Follow-up measures will be assessed online and/or by telephone calls 3 months past registration.

Intervention type

Other

Phase

Not Applicable

Drug names

Primary outcome measures

The primary outcome is the quantity of weekly cannabis use (measured in number of predefined average standard joints per week according to a consumption diary).

Secondary outcome measures

1. Number of cannabis use days per week
2. Severity of cannabis use (CUDIT)
3. Severity of cannabis dependence (SDS)
4. Cannabis withdrawal symptoms (CWS)
5. Cannabis craving symptoms (CCS-7)
6. Other psychoactive substance use
7. Brief Symptom Inventory (BSI-18)
8. Health status (EQ-5D-L)
9. Treatment retention
10. Treatment satisfaction

Overall trial start date

31/08/2013

Overall trial end date

31/08/2015

Reason abandoned

Eligibility

Participant inclusion criteria

1. Minimal age 18, either sex
2. At least once a week cannabis use in the past 30 days prior to study entry

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

267

Participant exclusion criteria

1. Current serious psychiatric illness or history of psychosis, schizophrenia, bipolar type I disorder or significant current suicidal or homicidal thoughts
2. No other pharmacological or psycho-social treatment for cannabis use disorders at study entry
3. Inability to read or write in German
4. For women: pregnancy or breastfeeding

Recruitment start date

31/08/2013

Recruitment end date

31/08/2015

Locations

Countries of recruitment

Switzerland

Trial participating centre

Swiss Research Institute for Public Health and Addiction (ISGF)
Zurich
8031
Switzerland

Sponsor information

Organisation

Swiss Office for the Coordination of Addiction Facilities - infodrog (Switzerland)

Sponsor details

c/o Alwin Bachmann
Eigerplatz 5
Postfach 460
Bern 14
3000
Switzerland

Sponsor type

Government

Website

http://www.infodrog.ch

Funders

Funder type

Government

Funder name

Swiss Office for the Coordination of Addiction Facilities - infodrog (Switzerland)

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

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: http://www.ncbi.nlm.nih.gov/pubmed/24228630
2015 results in http://www.ncbi.nlm.nih.gov/pubmed/26462848

Publication citations

  1. Protocol

    Schaub MP, Haug S, Wenger A, Berg O, Sullivan R, Beck T, Stark L, Can reduce--the effects of chat-counseling and web-based self-help, web-based self-help alone and a waiting list control program on cannabis use in problematic cannabis users: a randomized controlled trial., BMC Psychiatry, 2013, 13, 305, doi: 10.1186/1471-244X-13-305.

Additional files

Editorial Notes

16/10/2015: Publication reference added.