Social Media Intervention for Cannabis Use in Emerging Adults
Phase: NA
Conditions: Cannabis Use
Sponsor: University of Michigan

Study Protocol 
v.7 – 11/18/2021 
 
IRBMED #: HUM00152202 
 
Study Title: Project Verdi 
 
Full Study Title: Social Media Intervention for Cannabis Use in Emerging Adults 
 
Principal Investigator: Erin E. Bonar, PhD 
 
Co-Investigators: Maureen A. Walton, MPH, PhD 
 
 
    Jason E. Goldstick, PhD 
 
NCT #: NCT04187989 
 
 

Background 
 
      
Cannabis use is prevalent among emerging adults (EAs)1, with national trends toward increasing use2 
and shifting cannabis-related attitudes.3 The National Survey on Drug Use and Health (NSDUH) data show the 
annual, monthly, and daily prevalence of cannabis use increased in 18-25 year-olds from 2002 to 2014.4 
Similarly, Monitoring the Future (MTF) data show daily cannabis use increased from 2007 to 2014 (from 3.5% 
to 5.9%) in college students and non-college EAs (5.0% to 6.9%).5 These increases are reflected in decreasing 
risk perceptions.4,6 Among EAs from 2002-2014, perceived risk of monthly and weekly cannabis used declined 
by 43% and 48%, respectively, with 75% of EAs stating cannabis is easy to obtain and decreases in perceived 
peer disapproval since 2008.5 In 2015, 23% of 18 year-olds reported having friends who use cannabis.7 These 
trends are consistent with cannabis risk factors among EAs: perceived availability, peer use, and being offered 
cannabis.8-14 Furthermore, shifting perceptions and increased prevalence are occurring in the context of 
changing cannabis policies.15 Legalization of cannabis for recreational use by adults (ages 21+) in 8 states 
(WA, NE, ME, MA, CA, OR, AK, CO) and the District of Columbia (D.C.) may impact the availability and use of 
cannabis by EAs who can purchase it legally, as well as potentially allowing diversion to those under age 21.  
The changing legal context and ongoing illegal use of cannabis highlight the urgent need for preventing 
cannabis-related problems in EAs. Early use promotes greater risk for developing substance use disorders and 
other problems in adulthood, including potentially increasing mortality risk.16 For example, early use may affect 
neuro-maturational changes to the developing brain, resulting in adverse emotional and cognitive changes.17-19 
Decision-making and inhibitory control are critical functions developing in adolescence and emerging 
adulthood, which can be compromised by cannabis use.19-21 Although cannabis use is related to long-term 
health problems (e.g., lung cancer, respiratory issues)22-24, the short-term effects of cannabis are also 
alarming.25-28 After acute use (<6 hours), cannabis can alter executive functions, such as: attention, decision-
making, inhibition/impulsivity, risk-taking, working memory, and concentration.18,29 Daily data suggest that 
cannabis is associated with increased impulsivity and hostility.30 Findings on executive functioning suggest 
increased propensity for risk behaviors, such as risky sex31,32 or impaired driving33,34; 10% of EAs reported 
past-year drugged driving1. Evidence supports adverse relationships between cannabis and psychiatric 
problems35, including emerging psychotic disorders.36,37 
There is an urgent need to reduce cannabis use among EAs, who have 
the highest prevalence. Given the role of peer influences in EAs’ drug use38, 
modifying perceived peer norms of cannabis use is a viable strategy. Thus, 
consistent with NIDA’s Strategic Plan for 2016-2020, which calls for researchers 
to “explore the potential for technology-based methods for delivering prevention 
interventions, such as…social media,” we seek to develop and test a social 
media (SM) intervention to address legal and illegal recreational cannabis use by 
EAs, delivered by peer coaches. SM provides the opportunity to intervene in EAs’ 
real-life contexts and to harness peer influences via peer-led interactions within a 
group-based intervention. The guiding framework for this intervention can be 
found in Figure 1.  
 
 
 
Objective 
 
The specific aim of this clinical trial is to:  
 
 
Aim #2: Test the preliminary efficacy of a cannabis intervention delivered by trained e-coaches (versus 
attention-placebo control; up to N=90 per group with a target enrollment of 72 per group) on primary outcomes 
of cannabis use (quantity, frequency) and hazardous use (i.e., consequences) and secondary outcomes of 
perceived risk of cannabis, peer approval/disapproval of cannabis use, cannabis impaired driving, other drug 
use, and alcohol use (quantity, frequency) 
Social Media Intervention Pilot RCT  
 
Enrollment: We will conduct a two-arm pilot RCT of the intervention compared to an attention-placebo control 
condition (n = up to 90 per group, target enrollment of 72 per group) for EAs who use cannabis at least 
3x/week. Eligible participants will complete a baseline survey, a post-test at 3-months, and a 6-month follow-
up. 
Figure 1. Guiding Conceptual Model 

 
Participants and Recruitment Procedure. Study participants will be recruited via sponsored advertisements 
appearing on social media websites (e.g., Facebook and Instagram). Advertisements will be targeted towards 
18-25 year olds in specific regions (e.g., states with legal recreational cannabis vs. not legal). When users click 
on the advertisement, they will be redirected to an online screening consent (with waiver of documentation ). 
Interested participants will be asked to provide consent in Qualtrics and answer a captcha question (for identity 
verification). Participants will have the option to print or save a copy of the informed consent before moving on 
to the online survey.   
 
Following determination of eligibility by completing a 5-minute survey, negative screens will receive a thank 
you page ending their participation in the study. This page will also include a pdf of a resource list with contact 
information for national organizations that can provide assistance in the areas of substance use and 
physical/mental health and well-being. No identifying information will be collected from participants who are not 
eligible for the study, although the IP address of the device used to complete the survey will be automatically 
recorded by Qualtrics.  
 
Eligible participants will be notified of their eligibility and asked to provide contact information for verification 
purposes and to contact them with instructions for baseline procedures completion. After completing the 
contact information form, participants will see a “Thank You” message that includes a link to the resource list.  
 
Those eligible will be invited to review an RCT consent form, directed to an online baseline survey and priority-
mailed a urine drug screen (UDS; uploading a photo of results, as in prior work137). Due to the COVID-19 
pandemic including the disruptions in work/research and participant concerns’ about receiving mailed 
packages, starting May 2020, baseline procedures will no longer include a UDS (as approved by the study’s 
NIDA Program Officer). Participants will upload a selfie with a timestamp to verify their identity; baseline 
compensation will be a $35 gift card for completing all procedures. Verified participants (e.g., captcha, verified 
survey completion time, IP address) will be randomized and join their assigned secret Facebook group 
(intervention/ control; separated by age [18-20, 21-25] and residence in states with/without legal recreational 
cannabis).  
 
Inclusion/Exclusion Criteria. Participants will be eligible for the screening survey if they are able to view and 
click on a social media ad, participants who cannot read English will be informally excluded. Participants will be 
eligible to participate in the study if they are 18-25 years old, self-report using cannabis at least 3x per week or 
more often in the past month, and have an active Facebook profile. Participants will be excluded if they fail 
identity verification based on: 1) IP addresses, 2) survey time completion, 3) repeat attempts, 4) survey 
responses, and 5) photo identification via a timestamped selfie sent to the RAs. Participants from an earlier 
intervention content development study used to determine content for this intervention will be excluded. 
 
Randomization and Consideration of Key Biological Variables.  Randomization to conditions will be 
balanced across groups based on sex and cannabis use (<daily vs. daily [~43% estimate]), using urn 
randomization. Groups will be conducted separately by age (18-20 vs. 21-25) and state residence (legal 
recreational cannabis vs. not) with 8 groups total (4 intervention; 4 control; N~20 per group). 
  
Intervention condition. Content will be posted daily in secret Facebook groups where participants are 
randomly assigned at enrollment (N~20 per group for this feasibility pilot). Secret group members are kept 
private; groups cannot be identified in a web or Facebook search and can only be joined via a personal 
Facebook invitation from study staff. Groups will be closed; with enrollment in the group within approximately 1 
month of baseline assessment. Peer e-coaches will post intervention content 6 times per day, 7 days per 
week, for 8 weeks, mostly during late afternoon and into evening/night to capture time after school or work. E-
coaches will also private message participants via other SM accounts (e.g., Twitter, Snapchat, Instagram) to 
notify them of trending posts and prompt them to visit the group. E-coaches will encourage discussion of 
content by utilizing open-ended questions and reflections, consistent with Motivational Interviewing (MI). They 
will reply to comments with MI strategies (e.g., reflection, affirmation), including managing sustain talk (e.g., 
come alongside, agree with a twist), tagging other participants’ or the original commenter to encourage 
discussion and engagement. Based on our ongoing Alcohol social media intervention on Facebook, we have 
developed an e-coach manual outlining basic MI principles, protocols for posting, risk assessment (e.g., how to 

respond if a participant posts about self-harm/suicidality), and e-coach professionalism (e.g., how to respond if 
a participant contacts the e-coach on their personal SM profile). The group process, although conducted online 
by peer e-coaches, is analogous to group therapy in a treatment setting where therapists introduce rules and 
guidelines for the group and share intervention content, eliciting feedback, and calling on group members to 
react or to share their own ideas. “Tagging” a participant on a post functions like calling on a group member. 
To harness the presence of peers, e-coaches will tag multiple participants to encourage interaction. Use of 
“likes” and reactions (e.g., “haha,” “sad,”) allow for members and coaches to provide support and affirmation. 
We have also revised the User Safety Agreement from our current alcohol-SMI RCT for use in this study which 
outlines guidelines for participation (e.g., privacy, no posting opportunities to buy or receive drugs; no racial or 
political slurs; respect and confidentiality). Participants must signify their agreement with the User Safety 
Agreement before receiving the group invitation. Groups will be monitored multiple times/day (including 
weekends, holidays) during the 8-week period by scheduled e-coaches and rotating on-call supervisors (all 
highly experienced in MI) who include the investigators, study coordinator, and our lab network of clinical post-
docs and clinical social workers, who work as a team across studies in our Center. We will note in the group 
cover photo, that we cannot monitor groups 24/7, and include crisis numbers.  
 
Attention-Control condition. Control participants will be assigned to secret Facebook groups where the e-
coaches (RAs) will post daily content (e.g., news, videos) unrelated to intervention topics for 8 weeks, using 
the same schedule as the intervention. Participants must agree to the User Safety Agreement; groups will be 
monitored.  
 
 
 
Follow-Up Procedures. Self-report data will be collected online via Qualtrics ($35 for 3-month post-test; $40 
for 6-month follow-up). Participants will be reminded to complete post-test and follow-up measures via e-mail, 
private Facebook messaging, text message, and phone calls. Participants will be mailed UDSs and return 
time-stamped photos of their results through Qualtrics, to encourage accurate reporting of cannabis use. Due 
to the COVID-19 pandemic, including the disruptions in work/research and participant concerns’ about 
receiving mailed packages, follow-up procedures will no longer include UDS starting May 2020 (as approved 
by the NIDA Program Officer).  
 
Measures. 
 
We will use reliable and valid measures from prior studies with adolescents and EAs.  
 
Screening Survey. To assess study eligibility and characterize the study sample, participants will be asked 
about their demographics41, social media involvement39,42-44, and health behaviors, including cannabis use45.  
 
Baseline and Follow-Up Assessments. Participants will be asked to self-report measures including: 
demographics; SM involvement; cannabis use, motives, consequences, and protective strategies; perceptions 
of peer approval, cannabis risk perceptions, etc. Primary dependent measures are cannabis quantity and 
frequency assessed in the Timeline Follow-back (TLFB170-172), hazardous use/consequences, risk perceptions 
and perceived peer approval. In May 2020 as approved by the study’s NIDA Program Official, all assessments 
will include questions pertaining to the impacts of the COVID-19 pandemic in order to provide important 
contextual information about substance use and psychosocial factors that may be related to study findings.  If 
there is incomplete/inconsistent timeline follow back answers study staff will contact participants by phone to 
clarify data. We will ask participants to self-administer UDSs at baseline and follow-ups, sending a 
timestamped photo of results to the study staff, since in-person UDSs are not possible in a national study. As 
described the recruitment and follow-up procedures above, as a result of the COVID-19 pandemic,  
participants will no longer receive a mailed UDS. The 3- and 6-month surveys will mirror the baseline survey 
measures with the inclusion of acceptability measures at 3-months and engagement with other group members 
measures at 3 and 6-months.  
 
 
We will use software we developed to analyze user engagement with content posted in groups, tallying 
reactions (e.g., reactions, likes) and comments on a post. Our software also uses automated linguistic coding 
for text posts to categorize content (e.g., cannabis-related); we have developed a list of drug terms, including 
slang, that will be used in this coding.  This automated process will be supplemented by RAs who will hand-
code non-text posts (e.g., videos) for topic and content.  

 
Pilot Verbal TLFB Collection 
For the final 6-month follow-up survey, starting Nov 2020, participants will be asked to indicate at the end of 
the survey if they are interested in participating in an additional follow-up interview. Of those who indicate they 
are willing to be re-contacted, we will randomly select and schedule a phone or video call with up to 20 
participants. On the call a member of the study team will complete a pilot verbal Timeline Follow Back semi-
structured interview (analogous to the Timeline Follow Back online survey measure they have completed at 
each study assessment) where participants will answer questions about their substance use in the past 30 
days. Participants will be paid $30 (online gift card) for completing this procedure. This pilot procedure is not 
part of the formal clinical trial analysis.  
 
 
Data analysis 
To assess changes in the primary dependent measures (perceptions of risk and peer approval, 
quantity/frequency of consumption, cannabis consequences) while controlling for the fact that this is an 
individually randomized group-treatment trial (IRGT), we will use we will use generalized linear mixed models 
(GLMMs). We will account for correlations between individual within the same Facebook group using random 
intercepts. To assess treatment effects at 3M and 6M outcomes, we will fit separate models for each follow-up 
that control for baseline measurement, as well as  age, sex, recreational cannabis status, and will quantify the 
treatment effect using the coefficient for the treatment/control indicator. Controlling for the baseline outcome is 
critical for guarding against regression to the mean in treatment effect estimation. We will convert the treatment 
effects to effect sizes (Cohen’s D) by dividing the mean difference by the (square root of) the total variation 
unaccounted for by the fixed effects in the model (i.e., the residual variance + the random effect variance). 
Confidence intervals for the effect sizes will be derived using estimated marginal means (averaged across sex) 
and the confidence intervals are produced from the estimated variance of the estimate, and the estimated 
residual degrees of freedom from the random effects model.  Overall, this approach is effectively the same as 
ANCOVA, but accounting for the IRGT design, and controlling for sex and the strata used in the randomization 
(age and recreational cannabis status). Our initial specification will be a linear mixed effects model (i.e. 
Gaussian error distribution) with only a random intercept to capture within-group dependence. As the need is 
ascertained through model diagnostics, we will examine other distributional choices (e.g., Poisson, Negative 
Binomial) and more complex random effects structures (e.g., autoregressive).  
 
Human Use Considerations and Protections 
 
Eligibility and study informed consent will be administered online (a waiver of documentation of consent is 
requested) as the first pages of the screening and baseline surveys, respectively. The consent document will 
include information on the general nature of the study, privacy rights, expectations for participation, the 
voluntary nature of participation, and that participation can be withdrawn at any time. Participants will also be 
assured that data will not be shared with anyone outside of the study team. Because of the sensitive nature of 
the information collected, as an added protection for subjects, this research is covered by a Certificate of 
Confidentiality from NIH. Study documents will make explicit the voluntary nature of the subjects’ participation 
as well as potential situations for breaking confidentiality (see below for more information about limitations to 
confidentiality). Participants will be informed that their answers to the screening questions will be used to 
determine their eligibility for a research study. No identifying information will be collected from those who 
complete the screen and are ineligible or choose not to participate in the study, although the IP address of the 
device used to complete the screening survey will be automatically recorded in Qualtrics.  
Since the age of majority varies across states (i.e., age 18 in most states, age 19 in Alabama and Nebraska, 
and age 21 in Mississippi), a waiver of parental consent is also requested for those participants who are in 
the study’s target age group but are under the legal age of consent in their state of residence (i.e., AL, NE, 
MS). The same consent document described previously will be used for minors and adults. According to the 
Federal regulations governing research (45 CFR 46),163 Section 116(d) allows a waiver of the parental 
permission requirement for informed consent when (a) the research involves no more than minimal risk, (b) the 
waiver would not adversely affect the rights and welfare of the participants, (c) the research could not 

practicably be carried out without a waiver, and (d) whenever appropriate, the participants will be provided with 
additional pertinent information after participation.  
a) This study involves no more than minimal risk. Every effort will be made to ensure that study 
participants are protected from risk. For screening eligibility, we will not collect any identifiers from participants 
unless they screen eligible for and are interested in enrolling in the main study. Screening data will be 
anonymous for those participants who are not eligible or interested in the main study. Participants will be 
informed in the consent document about the procedures taken to maintain and protect their confidentiality, 
including assigning unique ID, securing data on secure, password protected UM servers and that this study is 
covered by a Certificate of Confidentiality.  
b) The waiver of parental consent does not adversely affect the rights and welfare of the subjects (age 
18-20 in certain states). Screening data will be anonymous for those participants who are not eligible for the 
main Aim 1 baseline study, as well as those who are eligible but choose not to enroll in the main study. To the 
extent possible given legal requirements on information required in the informed consent, the consent form is 
written in simple terms that should be understandable to individuals of varying ages and education levels. 
Participants will be able to download a copy of the consent form which contains contact information for 
research study staff should questions arise following enrollment. Participants who are eligible for the study and 
are interested in continuing will provide contact information and can indicate the method they prefer for being 
contacted.  
c) The research could not practicably be carried out without a waiver: This research could not be 
practicably conducted without a waiver of parental consent because we would not be able to ensure 
confidentiality around the participant’s substance use if parental consent were required for participants under 
the age of majority in their state (age 18-20 in certain states). Lack of a waiver of parental consent would 
hinder recruitment, particularly of young adults engaging in high-risk behaviors, and more importantly, have the 
potential to severely limit the generalizability of the findings. Research shows lower rates of young adult 
enrollment when parental consent is required, and that participants with lower risk (less substance use) are 
disproportionally enrolled (higher risk/ greater use less likely to participate).  
d) Whenever appropriate, the participants will be provided with additional pertinent information. After 
completing the screening and baseline surveys, participants will receive a pdf of an electronic resource 
brochure with contact information for national and community resources, including suicide hotlines, mental 
health and substance use treatment, etc.  
We also request a waiver of consent for re-consent of minors (in states where the age of majority is greater 
than 18) who reach the age of majority in their state while participating in the study (between screening 
completion and baseline invitation). As described above, this study involves no more than minimal risk to 
subjects. Given the brief length of time in which a participant is part of this study, it will not be feasible to obtain 
immediate consent for any minors (age 18-20 in certain states) who reach the age of majority during the study. 
Furthermore, we anticipate that all study assessments will be completed online.    
Every effort will be made to ensure that study participants are protected from risks.  Although it is not expected 
that there will be any risks to participants because of online screening and baseline assessment procedures, 
the risk of violation of confidentiality exists because human participants are giving personal information. 
Consent documents will contain a statement explaining mandatory reporting requirements for information 
regarding child abuse and intention to harm self or others. We do not expect that participants will disclose such 
information in the context of this study, since our assessments do not inquire about these behaviors. However, 
we will notify participants when/if we must make any mandatory reports based on information they disclose and 
we will only disclose the minimum information necessary.  Participants will be informed in the consent about 
the procedures taken to maintain and protect their confidentiality.  

To minimize the risk of violating confidentiality, RAs will make every effort to ensure that study data are always 
kept confidential. Staff training procedures will include information about the importance of confidentiality and 
techniques to maintain confidentiality of all information reported by research participants. Staff will maintain 
human subjects and confidentiality certifications through the U-M Program for Education and Evaluation in 
Responsible Research and Scholarship system.  
Unique identification numbers will be assigned to participants. All computerized databases with survey data will 
identify participants by this number and will be saved on a secure, encrypted, password-protected server. For 
participant tracking, one electronic document will be maintained linking participants’ ID numbers to their 
names. This document will be kept in a restricted-access folder on a password-protected computer within a 
secure research server.  This document will be deleted as soon as the study is completed. All data will be 
collected specifically for use on this project.  
For the online surveys, participants will be reminded that they may refuse to answer any questions that make 
them uncomfortable and that they may terminate the assessment at any time.  As described above, all 
participants will also receive substance use and mental health resources after completing the screening and 
baseline surveys. Participants’ confidentiality will be breached by the research study only to protect the safety 
and welfare of research participants and only in accordance with state and federal law. 
Potential Benefits of the Proposed Research to Human Subjects and Others 
Participation in this study may not directly benefit participants. However, in previous studies conducted by our 
team, participants have expressed that they enjoy being a part of research that will directly help other young 
adults around their age. The assessments themselves could also benefit participants by asking them to review 
their substance use. Furthermore, all participants will receive a resource list with referral information including 
the suicide hotline and text line, substance use, and mental health treatment.   
Rationale for Including Special Vulnerable Populations. Although our participants are aged 18-25 and are not 
children per NIH definitions, this research will involve individuals considered children ages 18-20 in states 
where the age of majority is greater than 18. This age range is critical for this research because rates of 
cannabis use reach peak prevalence during this developmental period, and interventions targeting this age 
group can potentially prevent future escalation and consequences associated with use, which could have 
enormous public health impact.  It is important to include this vulnerable population because their feedback can 
enhance the acceptability of our intervention to other young adults between the ages of 18-20. All ethnicities 
and races will be included in the proposed studies, to the extent that they agree to participate in screening and 
meet eligibility criteria.  
Importance of the Knowledge to be Gained 
Given that cannabis use behaviors often peak in emerging adulthood, as well as the correlation with other 
substance use, the individual and societal cost of these behaviors, and the fact that many emerging adults are 
not in settings where they may receive traditional preventive services, the development of effective targeted 
prevention programs are clearly needed. Given the current penetration of social media into the lives of young 
people, the potential reach for interventions using this medium, and the ability to harness peer influences to 
create behavior change within a social network, the knowledge to be gained from this research is significant.  
The risks to participants are reasonable in relation to the importance of this knowledge to be gained and 
potential public health impact of developing an effective program to reduce the use of and consequences 
associated with cannabis use among emerging adults. 
 
 
 

 
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