Using Implementation Intentions to Reduce Cannabis Use

Study Overview
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Brief Summary
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The study will recruit frequent users of cannabis (defined at least fortnightly use) and randomize them either to: (1) form implementation intentions by linking situations in which they are tempted to use cannabis with strategies to avoid using cannabis in those situations by using a volitional help sheet, or (2) to consider the situations in which they are tempted to use cannabis alongside possible strategies to avoid using it as presented in the volitional help sheet but not to form implementation intentions. The effects on self-reported cannabis use will be assessed 1 month post-intervention. Predictors of cannabis reduction will also be examined.

Detailed Description
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Design: This study will use questionnaires to assess participants cannabis habits (frequency and amount of use) and then employ planning strategies to help them quit. Follow up questionnaires will be used to ascertain the success of planning on reduction in cannabis use. Sample Size: We plan to recruit a minimum of 60 participants in each condition (120 total) but aim to collect data from as many participants as possible. Recruitment: To participate in this study a person must be over the age of 18 and a frequent user of cannabis. The study will be advertised online on social media platforms. Procedure: Potential participants will follow an online link to a briefing sheet that provides information about the study. The sheet will also inform participants that they do not have to complete the questionnaire and that they can withdraw from the study at any time without giving a reason. Once they have read the briefing sheet and generated their personal identity code, as instructed, they will complete the questionnaire online. A month after the participants have completed the initial questionnaire they will receive a link to a follow-up questionnaire via email. Email addresses will be stored separately to study data and will be destroyed once the follow up phase has completed and their involvement in the study ends. Outcomes and Analysis: The main purpose of this study is to explore the role of planning in encouraging people to reduce cannabis use. Quantitative analysis will be conducted to assess the effects of planning on cannabis use reduction. The investigators expect to find that planning is effective in helping people reduce their use.

Official Title
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Randomized Controlled Trial of a Volitional Help Sheet in Cannabis Users

Conditions
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Cannabis Use

Intervention / Treatment
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* Behavioral: Volitional help sheet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Frequent cannabis user (at least fortnightly) Exclusion Criteria: Younger than 18 years of age Infrequent / no cannabis use (less than fortnightly)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Control (volitional help sheet)<br>Participants read a brief statement designed to encourage them to reduce their cannabis use (We want you to plan to reduce your cannabis use). Participants are presented with a table with two columns and twenty rows. Twenty 'high risk' situations (temptations) are presented in the left hand column and 20 appropriate responses (processes of change) are presented in the right hand column (see Armitage, 2008). Participants are told that identifying situations in which they were tempted to use cannabis and identifying ways to overcome those temptations had been shown to help people change their behaviour and are asked to tick critical situations/appropriate responses that might be useful to them. | Behavioral: Volitional help sheet<br>* Participants are asked to choose from a list of strategies for avoiding cannabis use.<br>|
| Experimental: Intervention (volitional help sheet)<br>Participants read a brief statement designed to encourage them to reduce their cannabis use (We want you to plan to reduce your cannabis use). Participants are presented with a table with two columns and twenty rows. Twenty 'high risk' situations (temptations) are presented in the left hand column and 20 appropriate responses (processes of change) are presented in the right hand column (see Armitage, 2008). Participants are told that identifying situations in which they were tempted to use cannabis and identifying ways to overcome those temptations had been shown to help people change their behaviour. Implementation intentions are formed by linking critical situations with appropriate responses by choosing an appropriate response from a drop down menu for each critical situation. | Behavioral: Volitional help sheet<br>* Participants are asked to choose from a list of strategies for avoiding cannabis use.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cannabis use reduction (amount) | Self-reported cannabis use -amount of cannabis (weight) | 1 month | 
| Cannabis use reduction (frequency) | Self-reported cannabis use - frequency of use (days per week) | 1 month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Self reported habit as measured by the automaticity subscale of the Self-Report Habit Index. | Self-reported habit (e.g., Using cannabis is something I do automatically: strongly agree - strongly disagree). | 1 month | 
| Self reported action control as measured by the scale developed by Sniehotta et al (2011) | Self-reported action control (e.g., During the last week I often had my intention to reduce my cannabis use on my mind: strongly disagree-strongly agree) | 1 month | 
| Self reported craving as measured by items from the mood and physical symptoms scale (MPSS) | self reported craving | 1 month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cannabis, Risk reduction