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Completed

NCT Number: NCT03845842

Using Implementation Intentions to Reduce Cannabis Use

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.

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Key information

Conditions

Cannabis Use Behavior Chemically-Induced Disorders Marijuana Abuse Mental Disorders Risk Reduction Behavior Substance-Related Disorders

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

The University of Manchester

Manchester, M13 9PL, United Kingdom

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Frequent cannabis user (at least fortnightly)

Exclusion criteria

  • Younger than 18 years of age
  • Infrequent / no cannabis use (less than fortnightly)

Treatment and study plan

Volitional help sheet

Behavioral

Participants are asked to choose from a list of strategies for avoiding cannabis use.

Primary outcomes

  1. Cannabis use reduction (amount)

    Time frame: 1 month

    Self-reported cannabis use -amount of cannabis (weight)

  2. Cannabis use reduction (frequency)

    Time frame: 1 month

    Self-reported cannabis use - frequency of use (days per week)

Secondary outcomes

  1. Self reported habit as measured by the automaticity subscale of the Self-Report Habit Index.

    Time frame: 1 month

    Self-reported habit (e.g., "Using cannabis is something I do automatically: strongly agree - strongly disagree).

  2. Self reported action control as measured by the scale developed by Sniehotta et al (2011)

    Time frame: 1 month

    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")

  3. Self reported craving as measured by items from the mood and physical symptoms scale (MPSS)

    Time frame: 1 month

    self reported craving

Sponsors and collaborators

Lead sponsor

University of Manchester

Other

Registry information

Official study title

Randomized Controlled Trial of a Volitional Help Sheet in Cannabis Users

Important dates

Study start
2019
Primary completion
2020
Study completion
2020
First posted
Feb 19, 2019
Registry last updated
Nov 8, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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