Randomised-Controlled Trial of an Online Brief Advice Intervention for Heavy Cannabis Users (RECALIBRATE)

This project will evaluate whether a brief online intervention focused on cannabis withdrawal can increase awareness and insight about cannabis use disorder among daily cannabis users. The study will employ a randomised controlled trial design comparing an intervention consisting of a short educational video on cannabis withdrawal and personalised feedback on the Cannabis Withdrawal Scale, against a control condition of a relaxation video and mood questionnaire.

The investigators will aim to recruit at least 100 daily cannabis users (minimum 25 days of cannabis use /month and minimum 3.5g cannabis/week [low-medium daily use]) through Prolific, an online research participant platform. Potential participants will complete a brief screening questionnaire (1 minute) to confirm that participants meet inclusion criteria, before randomisation. The experiment will last 10-15 minutes and will include baseline demographic and substance use measures, the intervention or control condition, and outcome measures.

The primary outcome will be cannabis use awareness and insight as measured by the Substance Use Awareness and Insight Scale (SAS). Secondary outcomes will include intention to change cannabis use. This study aims to determine whether a short online intervention can increase awareness about cannabis withdrawal among heavy users. If successful, subsequent studies will be designed to assess these outcomes over the longer-term.