A new study longitudinally investigated displayed marijuana references on Facebook among a cohort of U.S. college students. Incoming students from two U.S. universities were randomly selected to be invited to participate. Inclusion criteria were being between 17 to 19 years old at baseline, speaking English, and owning a Facebook profile. Researchers ‘friended’ participants in order to access the content on their profiles, then coded the content on these profiles. The primary coding variable was a displayed marijuana reference, which included posts, ‘likes,’ and comments that addressed attitudes, intentions, or behaviors related to marijuana. These constructs were chosen because the authors used the Theory of Reasoned Action as the theoretical underpinning of this study. Participants (n = 338) also completed interviews at baseline (before college) and once per year for the following four years. Interview variables included lifetime and past-month marijuana use and demographic characteristics. The sample was 56.1% female and 74.8% White. At the end of year four, the retention rate was 95.6%. The authors defined frequent marijuana use as three or more days of use within the past 28 days and very frequent use as 20 or more days of use within the past 28 days. Frequencies of Facebook display behaviors were compared across marijuana use groups using t-tests and Chi square analyses. The authors used generalized linear models to measure relative risks (RRs) and 95% confidence intervals (CIs) of the likelihood of displayed Facebook marijuana references associated with demographic characteristics and frequency of use. RRs to infer whether frequency of marijuana use was associated with greater likelihood of displayed Facebook marijuana references were also estimated. Results indicated 16.8% (n= 57) of the sample displayed marijuana references on Facebook at least once during the study period. Marijuana references were more common among participants who reported lifetime marijuana use than among those who did not (22% vs. 5%; p < 0.001). Among marijuana users, frequent users were more likely to have posted marijuana displays than non-frequent users (30% vs. 18%, p = 0.04). The most common type of Facebook display was ‘liking’ marijuana-related content. The likelihood of displaying marijuana references was strongly predicted by self-reported marijuana use prior to the display (RR = 3.9, 95% CI: 1.8, 8.4), adjusting for gender, race/ethnicity, and university at which participants were enrolled. Frequent marijuana users were significantly more likely to display marijuana references on Facebook than non-frequent users (RR = 1.7, 95% CI: 1.01, 2.8). Very frequent marijuana users were more than twice as likely to display marijuana-related content than non-very-frequent users (RR = 2.6, 95% CI: 1.5, 4.6). Across the study period, the frequency of all types of Facebook marijuana references decreased. The authors hypothesized this may be because participants instead posted them on other social media platforms. A limitation of this study was that, although the sample was representative of the two universities from which participants were recruited, it was likely not representative of other universities, which limits the generalizability of this study’s findings.
Take away: In this study, self-reported marijuana users were more likely to display marijuana-related references (i.e., ‘likes,’ posts) on Facebook than non-users across the five-year study period. In addition, frequency of marijuana use positively predicted likelihood of these displays.