However, many cannabis users are interested in receiving self-help materials to help them evaluate their own cannabis use without formal treatment . It is possible then, that this emerging health issue could be partially addressed through the development, evaluation and dissemination of scalable interventions that can be self-administered by people who engage in risky cannabis use. Several researchers have successfully evaluated face-to-face interventions for cannabis users, including brief interventions targeting risky use . Further, there are a limited number of single and multi-session Internet-based interventions that have demonstrated small but significant impacts on cannabis use . One type of brief online intervention incorporates personalized normative feedback, outdoor cannabis grow having as its central component the comparison of participant’s consumption to others of the same age and gender, and has largely been studied within college settings.
Additionally, such interventions can also include feedback about the personal risks and consequences of using cannabis as well as other educational information . Four trials employed versions of the same intervention and found promising corrections of normative misperceptions and an impact of the intervention on the amount of time spent ‘high’ or the experience of negative consequences related to cannabis use . Employing a different personalized normative feedback intervention, but again in college students, Lee and colleagues found no impact of the intervention on cannabis use . Finally, one trial did employ a non-college adult population and compared a brief versus an extended personalized feedback intervention for cannabis use, finding no evidence of a differential impact of the two interventions . Given this limited research base, particularly in non-college samples, more research is needed to determine the efficacy of personalized normative feedback interventions for risky cannabis use. Further, it is possible that the deregulation of cannabis as an illegal substance might impact on people’s normative perceptions, making it important to examine the effects of normative feedback interventions in regions where use of cannabis is legal.
Current cannabis users from across Canada were recruited using Facebook and Kijiji advertisements asking for people who were concerned about their cannabis use and who were interested in participating in a study to find ways to help people who were worried about their cannabis use. Potential participants who responded to the advertisement by clicking on the link to the study website were first provided a brief description of the study. Those who were interested clicked on a link which took them to an eligibility screener. Eligible participants were 18 years or older. Eligibility criterion for risky cannabis use was defined as a Involvement Screening Test ,cannabis grow equipment developed by the World Health Organization . A score of four or more on the ASSIST is indicative of moderate risk associated with cannabis use and is the level at which a brief intervention is recommended when encountered in a primary care setting. Indeed, sensitivity analyses recommend that a criterion of four be used to identify individuals “at-risk” in clinical settings . Failure to meet inclusion criteria comprised the exclusion criteria for this trial. Those found eligible were asked to provide informed consent after the eligibility screener had been completed. They were further asked to provide an email address as well as telephone number and mailing address as additional contact information. All participants were asked to provide permission for study staff to contact them via phone or mail for follow-up surveys if correspondence by email was unsuccessful.
Participants who completed the consent form and provided a real postal address were emailed a link to complete a baseline survey. A real postal address ensured that participants were not recruited in duplicate, and that the survey was completed by a person and not an Internet bot. An automated set of checks was programmed into the baseline survey to confirm the consistency in participants’ responses between the eligibility screener and the baseline survey . Briefly, participants were screened out if, on the baseline survey: 1) they reported no cannabis use; 2) their cannabis subscale ASSIST score totaled less than four; 3) ASSIST total score changed by more than 10 points from the eligibility screener; or 4) ASSIST item responses changed to “never” . Those who were not consistent in their responses were thanked for their participation but were excluded from the randomized trial. It is important to note that the time between the two surveys was on average less than 3 days . Those who completed the baseline survey were provided with a gift certificate of $10 from Amazon.ca in order to promote retention at this point in the trial.