Examining effects of medical cannabis narratives on beliefs, attitudes, and intentions related to recreational cannabis: A web-based randomized experiment

Accepted Manuscript Title: Examining effects of medical cannabis narratives on beliefs, attitudes, and intentions related to recreational cannabis: A web-based randomized experiment Authors: Sharon R. Sznitman, Nehama Lewis PII: DOI: Reference:

S0376-8716(18)30020-6 https://doi.org/10.1016/j.drugalcdep.2017.11.028 DAD 6773

To appear in:

Drug and Alcohol Dependence

Received date: Revised date: Accepted date:

18-8-2017 19-11-2017 20-11-2017

Please cite this article as: Sznitman, Sharon R., Lewis, Nehama, Examining effects of medical cannabis narratives on beliefs, attitudes, and intentions related to recreational cannabis: A web-based randomized experiment.Drug and Alcohol Dependence https://doi.org/10.1016/j.drugalcdep.2017.11.028 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Examining effects of medical cannabis narratives on beliefs, attitudes, and intentions related to recreational cannabis: A web-based randomized experiment*

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Sharon R. Sznitman a, [email protected] Nehama Lewis b, [email protected]

School of Public Health, University of Haifa, Eshkol Tower, Mt. Carmel, 3190501, Haifa, Israel

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Communication Department, University of Haifa, Rabin Complex 8032, Mt. Carmel, 3190501,

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Haifa, Israel

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Correspondence: Sharon R. Sznitman

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School of Public Health, University of Haifa

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Eshkol Tower, Mt. Carmel, 3190501 Haifa, Israel

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Phone: 972-4-828-8604

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[email protected]

Highlights

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 MC testimonials indirectly increase positive attitudes about recreational cannabis  Attribution of responsibility for disease moderates the indirect effect.  Cannabis prevention should address the role of media in shaping public opinion. Abstract

Background: This experimental study tests effects of exposure to video narratives about successful symptom relief with Medical Cannabis (MC) on attitudes, beliefs, and intentions related to recreational cannabis use.

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Methods: Patient video testimonials were modeled after those found in extant media coverage. Israeli participants (N = 396) recruited through an online survey company were randomly assigned to view a narrative or a non-narrative video containing equivalent information about MC. Video content was further manipulated based on whether the protagonist had a stigmatized disease or not, and whether attribution of responsibility for his disease was internal or external.

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Results: Exposure to patient testimonials indirectly increased positive attitudes, beliefs and

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intentions related to recreational cannabis use through changing attitudes, beliefs and intentions

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related to MC. Furthermore, exposure to narratives in which the patient was presented as not to

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blame for contracting his illness (external attribution) was associated with more positive attitudes, beliefs and intentions toward MC, a factor that was significantly associated with more positive

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attitudes, beliefs and intentions related to recreational cannabis use.

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Conclusions: These results suggest that narrative news media coverage of MC may influence

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public attitudes toward recreational cannabis. Because such media stories continue to be commonplace, it is important to examine potential spillover effects of this coverage on public

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perceptions of recreational cannabis. Cannabis prevention programs should address the role of media coverage in shaping public opinion and address the distinction between medical and

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recreational cannabis use.

Keywords: Medical cannabis legalization; Recreational cannabis use; Narrative; Stigma; Attribution; Attitudes

1. Introduction Increasingly more jurisdictions around the world have legalized Medical Cannabis (MC)

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for various indications (Sznitman and Zolotov, 2015). Israel has been running a MC program since the late 1990s (recreational cannabis use remains illegal). With the exception of 14 oncologists who have the authority to directly issue MC licenses, the MC recommendations of specialist physicians are referred to the MC unit of the Ministry of Health for license authorization. Licenses are only granted for specific conditions/symptoms and only following the exhaustion of other

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“conventional” therapeutic options.

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MC policies in Israel and elsewhere have generated scientific and political debate regarding

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possible unintended spillover effects. A central question is whether MC legalization makes

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recreational cannabis use more socially acceptable and thus leads to increased recreational use (Sznitman and Zolotov, 2015). Although most people who use cannabis will not experience

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clinical or social problems (Eisen et al., 2002; von Sydow et al., 2001; Wagner and Anthony,

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2002), cannabis consumption carries some risk of adverse consequences, including accidents and

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poor psychosocial outcomes (Hall, 2009; Hall, 2015). If a greater percentage of the general population consumes cannabis, even a small risk of adverse effects may have significant

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deleterious consequences for the health of the population (Rose, 1992). Despite concerns that MC legalization may lead to increased acceptance and use of

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recreational cannabis, extant research has not provided compelling evidence for a direct association (Schmidt et al., 2016). Instead, the literature suggests that MC commercialization and exposure to MC advertisements, rather than MC legalization per se, may influence use of and attitudes toward recreational cannabis (Schuermeyer et al., 2014; Sznitman and Zolotov, 2015).

Studies have found that perceived harmfulness of cannabis declined after MC commercialization in Colorado, while several indicators of problematic use increased (Davis et al., 2015; Schuermeyer et al., 2014). Another study found that a growing number of Californian students

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reported seeing MC advertisements, and ad exposure was associated with greater intention to use cannabis and a higher likelihood of recreational use one year later (D'Amico et al., 2015).

While exposure to advertisements is one mechanism through which MC legalization may influence recreational cannabis use, non-commercial MC media coverage is another plausible source of influence. However, to our knowledge no study has investigated such effects. This is

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problematic, as MC legalization has received widespread media coverage in the past few years

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(Kaiser, 2011; McGinty et al., 2016; Robledo and Jankovic, 2017; Sznitman and Lewis, 2015).

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The purpose of this study was to test the effects of videotaped patient testimonials about positive

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MC experiences (such as those found in actual media coverage) on attitudes towards recreational cannabis use.

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1.1 Media effects: Narratives vs. informational format

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A substantial proportion of Israeli media coverage about MC is in the format of patient

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narrative testimonials, e.g., patients telling their stories about how MC helped relieve symptoms of their medical conditions (Lewis et al., 2015). Similar narrative media stories are commonplace

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in Canada and the U.S. (ACLU, 2017; Gupta, S., 2013; Robledo and Jankovic, 2017). The prevalence of this format is important because patient narratives may exert a particularly strong

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influence on public opinion, as they offer a personal and emotional perspective (De Graaf et al., 2016). A growing number of studies have compared the persuasive effects of narrative and nonnarrative messages (Shen et al., 2015; Zebregs et al., 2015). A previously published study (based on the same research protocol and sample as the current study) experimentally tested the effects

of patient narratives about MC compared with informationally equivalent non-narrative (informational) messages. The study showed that exposure to narratives led to significantly more positive attitudes toward MC than informational messages. These effects were mediated through

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participants becoming emotionally and cognitively involved in the story and identifying with the patient telling the story (Lewis and Sznitman, 2017), which is consistent with research on narrative persuasion (Green and Brock, 2000; Slater and Rouner, 2002).

The current study tests the mechanisms by which MC media content may affect audience attitudes, beliefs and intentions towards recreational cannabis use. We propose that, compared to

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exposure to information in a non-narrative (informational) format, information about the

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effectiveness of MC for reducing painful symptoms that is presented in narrative form will be

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associated with more positive attitudes, beliefs and intentions towards recreational cannabis use.

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We also hypothesize that these effects will be partially mediated by positive attitudes towards MC (pre-registered hypotheses H1 and H2, https://osf.io/zk4sg/).

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1.2 Attribution of responsibility

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The strength of the effects of the narrative format may depend on specific factors within

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the narrative. This study focuses on two factors: attribution and stigma. According to attribution theory (Weiner, 1995), people are more likely to have positive attitudes towards patients and

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support policies that will help a patient if the cause of the patient's illness is attributed to external factors (i.e., factors beyond the control of the individual) than when their illness is perceived to be

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caused by internal factors (such as the individual’s behavior). However, a meta-analytic review of narrative effects in the context of health has found inconsistent support for the effects of responsibility attribution on attitudes (De Graaf et al., 2016).

This study tests the effects of attribution of responsibility for the patient’s illness on attitudes, beliefs, and intentions toward recreational cannabis use. We expect that indirect effects of MC patient narratives on attitudes, beliefs, and intentions towards recreational cannabis use

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(through attitudes toward MC) will be stronger when attribution of responsibility for the patient’s medical condition is external (e.g., not under his/her control) vs. internal (pre-registered hypothesis H3, https://osf.io/zk4sg/). Specifically, we expect path a in Figure 2 to be moderated by attribution. 1.3 Stigma

Stigma may also influence the effects of exposure to MC narratives on attitudes, beliefs,

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and intentions towards recreational cannabis use. Research shows that disease-related

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stigmatization negatively impacts public attitudes towards treatment and related health policies

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(Pryor et al., 1999). One of the first promising treatment applications of MC was for AIDS-related

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wasting syndrome (Prentiss et al., 2004). Nearly all MC jurisdictions have approved MC for HIV/AIDS patients, although AIDS remains a highly stigmatized condition (Von Collani et al.,

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2010). Thus, the effects of MC narratives on audience attitudes may vary depending on whether

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the patient is said to suffer from HIV or a less stigmatized condition (e.g., cancer). We hypothesize

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that the indirect effects of MC narratives on attitudes, beliefs, and intentions towards recreational cannabis use (through MC attitudes) will be weaker when the patient has a stigmatized disease

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(AIDS) than when he has a non-stigmatized disease (cancer) (pre-registered hypothesis H4,

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https://osf.io/zk4sg/). Specifically, we expect path a in Figure 2 to be moderated by stigma. 2. Methods 2.1 Sample and procedures Power analyses in SAS 9.4 (SAS, 2017) showed that, in a regression model with the required number of predictors (11 predictors in full model; 10 in reduced model) under the

assumption of partial correlation > 0.18 and nominal power < 0.8, a sample size of 250 was sufficient. The inclusion criteria were ability to speak, write and read Hebrew and age ≥ 18 and ≤ 60. The age criteria were determined so that the sample only included adults, and that younger and

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older respondents would deviate similarly in age from the age of the media message protagonist (age = 40). Israeli Jewish participants (N= 477) were recruited through Panel4all, a leading provider of internet survey data for academic researchers in Israel. Participants were offered vouchers in exchange for their participation by the survey company.

Participants were asked to rate the technical quality of the video they watched. Participants

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who reported “poor video quality” were excluded from the study (n = 41). We also excluded 81

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participants who took less than seven minutes or over three hours to complete the survey, leaving

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an analytic sample of 396 participants (see Figure 1 CONSORT flow diagram).

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We employed a 2 (message format: narrative vs. informational) by 3 (disease type: cancer, HIV, and a control disease: cholesterol) by 2 (attribution: protagonist responsible vs. not

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responsible) between-subjects experimental design. Panelists were invited to participate with a

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link that sent them to a website where they clicked on one of 12 available links (for each condition),

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viewed the allocated video, and answered a survey. The ethics review board of the University approved all procedures.

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2.2 Stimuli

Twelve short scripts (see supplemental material1) were developed for the production of

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three-minute videos featuring the same protagonist – a male, 40 years of age. The message content was uniform across conditions (length and causal sequence) besides the manipulated factors:

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Supplementary material can be found by accessing the online version of this paper at http://dx.doi.org and by entering doi:...

format (narrative vs. informational), disease stigma (HIV vs. cancer), and attribution (HIV: Illicit drug use vs. sexual transmission by an infected partner whose positive HIV status was undisclosed to the protagonist; cancer: smoking vs. genetic factors).

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The story arc draws from elements that were featured across a number of patient testimonials that were examined in a previous content analysis of actual patient testimonials found in Israeli MC news coverage (Lewis and Sznitman, 2017; Sznitman and Lewis, 2015). Specifically, in all narrative messages the protagonist’s story included the following elements: (1) the initial diagnosis of the disease and its attributed cause, (2) the development of painful symptoms, and (3)

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unsuccessful medical treatments and consequent frustration. The protagonist then describes (4)

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being offered MC by a friend, (5) his positive experience with MC, (6) an initial unsuccessful

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attempt to apply for a MC license, (7) a second, successful attempt, and (8) his positive

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endorsement of treatment with MC for his disease. This narrative message structure meets Ryan’s (2007) criteria for a narrative message. Specifically, the protagonist is an individual entity who

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describes events that are bounded in time and involve cause and effect relationships. The story

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describes different actors (doctors, friend) with whom the protagonist interacts, as well as

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purposeful action taken by the protagonist. The story is concluded in a way that provides closure, is described as factual, and communicates something meaningful for the audience.

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Control narratives were developed to confirm that narrative vs. informational effects on attitudes, beliefs, and intentions towards recreational cannabis use were unsupported in an

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unrelated health context. The control narrative format was comparable in length and causal sequence to the MC narratives, but instead of describing MC treatment these narratives described the protagonist’s (unsuccessful) treatment of high cholesterol with prescription drugs (statins) and

the suggestion by a friend to adopt a healthier lifestyle (see supplemental material2). More information about the cholesterol condition can be found in Lewis and Sznitman (2017). To compare narrative messages with messages that are comparable with regard to the

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information provided to the audience, but differ from Ryan’s (2007) criteria for what a narrative structure consists of, six videos were developed in an informational (non-narrative) format (two MC-HIV, two MC-cancer, and two cholesterol). The scripts for informational messages were similar to the narrative messages (same length, causal sequence and actor), but elements were described in an informative manner rather than as a personal testimonial (see online supplement2).

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2.3 Measures

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2.3.1 Independent variable. The independent variable was coded 0 = informational format

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or 1 = narrative format.

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2.3.2 Mediator. Attitudes, beliefs and intentions toward MC were measured by asking participants the extent to which they agreed (1 = “completely disagree” through 5 = “completely

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agree”) with the following statements: “the benefits of using MC outweigh the risks involved in

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its use”; “cannabis can be helpful for people with specific illnesses”; “there is an empirical basis

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that supports the use of MC”; “MC has fewer side effects compared with other prescription treatment options”; “if someone close to me was sick and using MC could help him/her, I would

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recommend him/her to apply for a license from the Ministry of Health”; and “MC should be in the

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treatment 'basket', so that patients don't have to pay for it out of pocket”.

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Supplementary material can be found by accessing the online version of this paper at http://dx.doi.org and by entering doi:...

2.3.3 Moderators. Respondents were coded 0 if they were in the stigmatized illness condition (HIV) and 1 if they were not (cancer). They were coded 0 if they were in the external attribution condition and 1 if they were in the internal attribution condition.

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2.3.4 Dependent variable. Attitudes, beliefs, and intentions towards recreational cannabis use were measured by asking participants to state the extent to which they agreed (1 = “completely disagree” – 5 = “completely agree”) with the following statements: “cannabis use for all purposes (medical and recreational) should be legal”; “we need to accept that recreational cannabis use is a normal part of some people’s lives”; “people usually have a good time when they use cannabis”;

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“using cannabis once a month is not dangerous”; “I would use cannabis for recreational purposes

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if a friend offered it to me”; “the sale of small amounts of cannabis for recreational purposes from

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one adult to another should not be a criminal offence”; and “if I wanted to I could attain cannabis

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for personal use.” 2.4 Statistical analyses

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Two separate Confirmatory Factor Analyses (CFA) were conducted to investigate the

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construct validity of the items measuring attitudes, beliefs, and intentions towards recreational

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cannabis and towards MC. The following fit indices values were used as indication of adequate fit: Comparative Fit Index (CFI) > 0.95, Tucker–Lewis Index (TLI) > 0.90, and Root Mean Square

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Error of Approximation (RMSEA) < 0.06 (Hu and Bentler, 1999). The mean of the items was calculated such that a higher score indicates more positive attitudes, beliefs, and intentions toward

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(1) recreational cannabis use and (2) MC use. To test whether MC narratives would have direct (H1) and indirect (H2) effects on

attitudes, beliefs and intentions towards recreational cannabis use through MC attitudes, we conducted a mediation analysis using SPSS (2013) with PROCESS model 4 (Hayes, 2013). To

examine whether attribution of responsibility and/or stigma moderate the indirect effect, we conducted two separate moderated mediation analyses in which PROCESS model 14 produced an index of moderated mediation that quantifies the effect of a moderator variable on a mediation

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effect (Hayes, 2015). We tested all the models just described among subjects who were exposed to videos about cholesterol to verify that effects of narratives were not present in an unrelated health condition. Furthermore, to test main effects of exposure to messages about MC on recreational cannabis attitudes, beliefs, and intentions, compared to the control conditions (cholesterol), we ran models

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similar to those described above but with a dummy variable for whether or not respondents had

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viewed a cholesterol or MC message. Results of manipulation checks for message format

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(narrative vs. informational), disease type manipulation (stigmatized vs. non-stigmatized), and

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attribution of responsibility have been reported elsewhere (Lewis and Sznitman, 2017). Participants’ gender, socioeconomic attitudes (higher values equals more liberal attitudes),

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cigarette use, and cannabis use were significantly associated with attitudes toward medical and/or

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recreational cannabis use (all p < .05) and were thus included as covariates. Furthermore, we

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included reported technical quality of the video as a covariate (‘very good’ vs. ‘good’). Stigma was entered as a covariate in the model with attribution as the moderator, and attribution was

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entered as a covariate in the model with stigma as the moderator variable.

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3. Results 3.1 Descriptives The mean age of the sample was 29.6 (SD = 6.0), and 53% were female. Similar to

characteristics reported in national census reports (CBS, 2015), most participants (61%) had completed 12 or more years of school, and 50% were married/cohabiting. Exposure to narrative

messages was associated with positive MC attitudes, beliefs, and intentions (p = 0.02, Table 1). Attribution and stigma were not correlated with MC or recreational cannabis attitudes, beliefs, and intentions (p > 0.05). Cannabis and cigarette use were positively correlated with attitudes, beliefs,

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and intentions toward MC (p < .001). Males, individuals with more liberal socioeconomic attitudes, current smokers, and cannabis users were more positive toward recreational cannabis use than others (p values < .05).

According to CFA fit indices, items measuring attitudes, beliefs, and intentions towards MC and recreational cannabis had adequate fit (Table 2). Furthermore, standardized factor

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loadings were satisfactory (range: 0.45 - 0.99) which suggests that the items measure the intended

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constructs.

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3.2 Mediation

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Exposure to narrative format was not directly associated with attitudes, beliefs, and intentions towards recreational cannabis use (b = -0.14, p = .32; see Figure 2). Narrative format

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was, however, associated with positive attitudes, beliefs and intentions towards MC (b = 0.27, p =

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.05), and this in turn was associated with positive attitudes, beliefs, and intentions towards

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recreational cannabis use (b = 0.44, p < .001). The bootstrapping approach showed that the indirect effect of narratives on attitudes, beliefs and intentions towards recreational cannabis was

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significant (b = 0.12, 95% CI [0.003, 0.27]), thus supporting H2 but not H1.

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3.3 Moderated mediation There was no significant interaction effect of stigma and narratives on attitudes, intentions,

and beliefs toward recreational cannabis (b = 0.45, p = .10). Thus, H3 was not supported. There was, however, a significant interaction effect of attribution and narratives (b = - 0.81, p = .003), whereby attribution moderated the effect of narratives on attitudes, beliefs and intentions toward

MC. This was, in turn, positively associated with attitudes, beliefs, and intentions toward recreational cannabis (b = 0.44, p < .00; see Table 3). The moderated mediation index was significant (b = -0.35, 95% CI [-0.625, -0.137]) and thus, supported H4.

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Specifically, these results show that there was a significant positive mediated effect of narrative format on attitudes, beliefs, and intentions toward recreational cannabis through MC attitudes among participants in the external attribution condition (b = 0.30, 95% CI [0.141, 0.530]). In contrast, among participants who were exposed to narratives in which the protagonist was to blame (i.e., the internal attribution), there was no significant mediated effect (b = -0.05, 95% CI [-

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0.213, 0.106]. Taken together, this shows that exposure to narratives in which the patient was

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presented as not to blame for his illness was associated with more positive MC attitudes, beliefs,

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intentions towards recreational cannabis use.

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and intentions. This factor was significantly associated with more positive attitudes, beliefs, and

When we replicated the above models with participants who viewed the cholesterol

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messages, results showed no effect (p > 0.05) of narrative format on the mediator, moderators, or

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dependent variable (results available upon request).

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4. Discussion

Rapid shifts in MC policies have been associated with an accompanying increase in media

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coverage about issues pertaining to the therapeutic and largely positive effects of cannabis. Patient testimonials (narratives) comprise a significant proportion of such news items in Israel (Lewis et

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al., 2015) and likely elsewhere (Robledo and Jankovic, 2017), due to the expectation that patient testimonials are particularly effective at eliciting audience sympathy and attention (Green and Brock, 2000; Slater and Rouner, 2002).

There are no available data to estimate the frequency at which the Israeli public is exposed to MC testimonials. Israeli media coverage tends to focus heavily on security and political issues related to the Palestinian-Israeli conflict at the expense of coverage of other topics, including

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health. A previous study found that the overall number of newspaper articles focusing on MC was fairly small (Sznitman and Lewis, 2015). However, news items focusing specifically on MC comprised approximately 20% of all coverage about cannabis, suggesting that MC is an important issue.

This study provides experimental evidence that exposure to patient testimonials regarding

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the efficacious use of MC indirectly influences attitudes, beliefs and intentions towards

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recreational cannabis use through MC attitudes. A shift in public opinion regarding recreational

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cannabis use is likely to have implications for policy and public health. Indeed, research shows

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that perceptions of harm (Bachman et al., 1998) and approval of cannabis (Wu et al., 2015) are important predictors of recreational cannabis use. While the current study does not test the effects

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of exposure to MC narratives on recreational use, it provides a first indication that such exposure

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influences important determinants of recreational use. Furthermore, other data show increases in

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the use of recreational cannabis use since the expansion of the Israeli MC program (Harel-Fisch, 2017). Research from the U.S. shows that shifts towards cannabis legalization corresponds to shifts

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in public attitudes, and the proportion of Americans stating that cannabis should be legal increased from 12% in 1969 to 53% in 2015 (Pew Research Center, 2015). Future studies should test the

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effects of MC media exposure on cannabis use and policy directly. The study findings raise important questions about the role of attribution of responsibility

in shaping public attitudes toward MC and recreational cannabis. The results suggest that whether a patient has a stigmatized illness does not impact effects of exposure to MC narratives on attitudes,

beliefs, and intentions toward recreational cannabis. In contrast, when the protagonist is presented as an innocent victim there was a mediated effect of narrative format on attitudes, beliefs, and intentions toward recreational cannabis. Journalists and other interest groups covering this topic

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should be aware that attribution of responsibility can affect the audiences’ reaction to the narrative protagonist (e.g., a patient) and their attitudes toward MC and recreational cannabis.

The current study focuses on the effects of message format (e.g., narrative vs. informational messages). We did test for main effects, i.e., whether participants exposed to MC messages reported more positive attitudes, beliefs, and intentions toward recreational cannabis use than

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participants exposed to messages about cholesterol. No significant main effect was found. One

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possible explanation for this is that the Israeli public may be predisposed to hold positive attitudes

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toward MC; this explanation is supported by research (Sznitman and Bretteville-Jensen, 2015).

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Consequently, among individuals exposed to an unrelated message, the baseline attitude toward medical and recreational cannabis may be relatively positive. However, our results suggest that

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public attitudes, beliefs, and intentions might still be influenced by exposure to messages about

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MC. Compared with expository messages, MC media messages in narrative format are likely to

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reinforce or enhance extant positive attitudes, beliefs, and intentions, particularly when the protagonist is not to blame for his illness.

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From the perspective of recreational cannabis use prevention, the current study suggests that efforts should be made to assess potential harmful spillover effects of exposure to MC media

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narrative coverage. This may be particularly relevant for jurisdictions in which MC receives significant media coverage (e.g., where MC legalization is likely to occur or has occurred). Furthermore, cannabis prevention programs, informed by underlying public health philosophy and associated problem-focused perspectives, typically emphasize detrimental effects of cannabis

without recognizing its therapeutic effects. Since the therapeutic effects of cannabis are increasingly being discussed in the public sphere, it may be necessary for prevention programs to develop more nuanced prevention strategies that address both the risks and the potential

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therapeutic effects of cannabis. 4.1 Methodological considerations

All messages were scripted to be of similar duration and featured the same protagonist in order to avoid potentially spurious effects of vividness or source factors unrelated to the hypotheses (Niederdeppe et al., 2011). Future studies that attempt to replicate the current results

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with stimuli using different actors are needed to enhance external validity. Furthermore, the single

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character method used could have raised questions among respondents in the non-narrative

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condition if they thought it was strange that a supermarket manager (the job description of the

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person talking in the video) would provide general information about MC (in the narrative condition the supermarket manager was an MC patient which is unlikely to have seemed strange).

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To test whether this factor influenced the evaluation of narrative and non-narrative messages, we

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compared self-reported counter-arguing across the two message format conditions. Results of an

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ANOVA test showed no significant differences (f(1, 266) = 1.22, p = 0.37) between the narrative (M = 2.59, SD = 1.32) and non-narrative (M = 2.42, SD = 1.23) conditions. Thus, the admittedly

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unusual juxtaposition between the source’s occupation and message content in the non-narrative message conditions does not seem to have impacted the recipients’ evaluation of these messages

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in this study.

To the best of our knowledge there is no validated scale for measuring beliefs, attitudes,

and intentions towards MC and recreational cannabis use. Although closely related (Fishbein and Ajzen, 2011), these concepts are typically measured separately. Since the current study did not

focus on the distinctions between the concepts, we used a global measure including belief, attitude, and intention items that have been separately used in previous research (Fetherston and Lenton, 2005; Schulenberg et al., 2017; Sznitman and Bretteville-Jensen, 2015). We tested the construct

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validity of the items using CFA and found that the items measure the intended constructs. There is, however, clearly a need for scale development in this area. Lastly, the simulated environment used in the experimental study reduces ecological validity. Future studies in naturalistic settings are needed. 5. Conclusions

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More research is needed to address the questions of how and whether media coverage of

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MC influences attitudes toward recreational cannabis and related harm. Nevertheless, a cautious

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interpretation of the findings suggests that investment in evidence-based prevention programs in

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jurisdictions that may legalize MC or have already done so is warranted. Results also suggest that new cannabis prevention programs are needed that explicitly address the blurred boundaries

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Author Disclosures

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between medical and recreational use of cannabis.

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Role of Funding Source

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Nothing declared.

Contributors All authors have contributed significantly and agree to the submission of the final manuscript. Sharon R. Sznitman directed the analysis, interpreted the findings and was the principle author of

the paper. Nehama Lewis designed the study, contributed to the interpretation of the findings and writing of the paper.

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Conflict of interest

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None.

References American Civil Liberties Union, 2017.Cancer patient speaks out about medical marijuana [video]. https://www.aclu.org/video/cancer-patient-speaks-out-about-medical-marijuana.

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Bachman, J., Johnston, L., O'Malley, P., 1998. Explaining recent increases in students' marijuana use: Impacts of perceived risk and disapproval, 1976 through 1996. Am. J. Publ. Health. 88, 887-893.

Central Bureau of Statistics, 2015. The population of Israel in the year 2015-2016. http://www.cbs.gov.il/reader/cw_usr_view_Folder?ID=141.

U

D'Amico, E.J., Miles, J.N., Tucker, J.S., 2015. Gateway to curiosity: Medical marijuana ads and

N

intention and use during middle school. Psychol. Addict. Behav. 1, 1.

A

Davis, J.M., Mendelson, B., Berkes, J.J., Suleta, K., Corsi, K.F., Booth, R.E., 2016. Public health

M

effects of medical marijuana legalization in Colorado. Am. J. Prev. Med. 50, 373-379. De Graaf, A., Sanders, J., Hoeken, H., 2016. Characteristics of narrative interventions and health

D

effects: A review of the content, form, and context of narratives in health-related narrative

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persuasion research. Rev. Commun. Res. 4, 88-131.

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Eisen, S.A., Chantarujikapong, S., Xian, H., Lyons, M.J., Toomey, R., True, W.R., Scherrer, J.F., Goldberg, J., Tsuang, M.T., 2002. Does marijuana use have residual adverse effects on

CC

self-reported health measures, socio-demographics and quality of life? A monozygotic cotwin control study in men. Addiction 97, 1137-1144.

A

Fetherston, J. and Lenton, S., 2005. Effects of the Western Australian Cannabis Infringement Notice Scheme on public attitudes, knowledge and use - Baseline, year 1. Perth, National Drug Research Institute.

Fishbein, M. and Ajzen, I., 2011. Predicting and changing behavior: The reasoned action approach. New York, Taylor and Francis. Green, M., Brock, T., 2000. The role of transportation in the persuasiveness of public narratives.

Gupta,

S.,

2013.

“Why

I

changed

my

SC RI PT

J. Pers. Soc. Psychol. 79, 701-721. mind

on

weed.”

CNN.

http://www.cbs.gov.il/reader/cw_usr_view_Folder?ID=141.

Hall, W., 2009. The adverse health effects of cannabis use: What are they, and what are their implications for policy? Int. J. Drug Pol. 20, 458-466.

U

Hall, W., 2015. What has research over the past two decades revealed about the adverse health

N

effects of recreational cannabis use? Addiction 110, 19-35.

A

Harel-Fisch, Y., 2017. Dramatic increase in cannabis use among young and adult populations in

M

Israel: The ‘normalization’ effects of the intense public debates regarding cannabis legalization and medicalization. In: Proceedings of Lisbon Addictions; Lisbon, Portugal.

D

Hayes, A.F., 2013. Introduction to mediation, moderation, and conditional process analysis: A

TE

regression-based approach. New York, The Guilford Press.

EP

Hayes, A.F., 2015. An index and test of linear moderated mediation. Mult. Behav. Res. 50, 1-22. Hu, L.T., Bentler, P.M., 1999. Cutoff criteria for fit indexes in covariance structure analysis:

CC

Conventional criteria versus new alternatives. Struct. Equ. Modeling 6, 1-55.

A

Kaiser, C.L., 2013. "Medical issue or policy? a framing analysis of the medical marijuana issue in U.S. newspapers." Louisiana State University and Agricultural and Mechanical College: LSU Master's Theses, 4141.

Lewis, N., Broitman, D., Sznitman, S.R., 2015. Medical cannabis: A framing analysis of Israeli newspaper coverage. Sci. Commun. 37, 675-702.

Lewis, N., Sznitman, S.R., 2017. You brought it on yourself: The joint effects of message type, stigma, and responsibility attribution on attitudes toward medical cannabis. J. Commun. 67, 181-202.

SC RI PT

McGinty, E.E., Samples, H., Bandara, S.N., Saloner, B., Bachhuber, M.A., Barry, C.L., 2016. The emerging public discourse on state legalization of marijuana for recreational use in the US: Analysis of news media coverage, 2010–2014. Prev. Med. 90, 114-120.

Niederdeppe, J., Shapiro, M.A., Porticella, N., 2011. Attributions of responsibility for obesity: Narrative communication reduces reactive counterarguing among liberals. Hum. Commun.

U

Res. 37, 295-323.

http://www.people-press.org/2015/04/14/in-debate-over-legalizing-marijuana-

M

disagreement-over-drugs-dangers/2.

A

dangers.

N

Pew Research Center, 2015. In debate over legalizing marijuana, disagreement over drug’s

Prentiss, D., Power, R., Balmas, G., Tzuang, G., Israelski, D.M., 2004. Patterns of marijuana use

D

among patients with HIV/AIDS followed in a public health care setting. J. Acquir. Immune

TE

Defic. Syndr. 35, 38-45.

EP

Pryor, J.B., Reeder, G.D., Landau, S., 1999. A social-psychological analysis of HIV-related stigma. Am. Behav. Sci. 42, 1193-1211.

CC

Robledo, I., Jankovic, J., 2017. Media hype: Patient and scientific perspectives on misleading medical news. Mov. Disord. 32, 1319-1323.

A

Rose, G, 1992. The strategy of preventive medicine. Oxford, Oxford University Press. Ryan, M.L., 2007. Toward a definition of narrative. In: Herman, D. (Ed.), The Cambridge companion to narrative. Cambridge: Cambridge University Press: p. 22-35. SAS, 2017. Institute Inc. Base SAS®9.4. Procedures Guide. SAS Institute, Cary, NC.

Schmidt, L.A., Jacobs, L.M., Spetz, J., 2016. Young people’s more permissive views about marijuana: Local impact of state laws or national trend? Am. J. Publ. Health 106, 14981503.

SC RI PT

Schuermeyer, J., Salomonsen-Sautel, S., Price, R.K., Balan, S., Thurstone, C., Min, S.-J., Sakai, J.T., 2014. Temporal trends in marijuana attitudes, availability and use in Colorado compared to non-medical marijuana states: 2003-2011. Drug Alcohol Depend. 140, 145155.

Schulenberg, J.E., Johnston, L.D., O'Malley, P.M., Bachman, J.G., Miech, R.A., Patrick, M.E.,

U

2017. Monitoring the Future national survey results on drug use, 1975-2016: Volume II,

N

college students and adults ages 19-55. Ann Arbor: Institute for Social Research, The

A

University of Michigan.

M

Shen, F., Sheer, V.C., Li, R., 2015. Impact of narratives on persuasion in health communication: A meta-analysis. J. Advert. 44, 105-113.

D

Slater, M.D., Rouner, D., 2002. Entertainment—education and elaboration likelihood:

TE

Understanding the processing of narrative persuasion. Commun. Theory 12, 173-191.

EP

SPSS, I., 2013. IBM SPSS Statistics for Windows. IBM Corp., Armonk, NY. Sznitman, S.R., Bretteville-Jensen, A.L., 2015. Public opinion and medical cannabis policies:

CC

Examining the role of underlying beliefs and national medical cannabis policies. Harm Reduct. J. 12, 46.

A

Sznitman, S.R., Lewis, N., 2015. Is cannabis an illicit drug or a medicine? A quantitative framing analysis of Israeli newspaper coverage. Int. J. Drug Policy 26, 446-452.

Sznitman, S.R., Zolotov, Y., 2015. Cannabis for therapeutic purposes and public health and safety: A systematic and critical review. Int. J. Drug Policy 26, 20-29.

Von Collani, G., Grumm, M., Streicher, K., 2010. An investigation of the determinants of stigmatization and prejudice toward people living with HIV/AIDS. J. Appl. Soc. Psychol. 40, 1747-1766.

SC RI PT

von Sydow, K., Lieb, R., Pfister, H., Höfler, M., Sonntag, H., Wittchen, H.-U., 2001. The natural course of cannabis use, abuse and dependence over four years: A longitudinal community study of adolescents and young adults. Drug Alcohol Depend. 64, 347-361.

Wagner, F.A., Anthony, J.C., 2002. From first drug use to drug dependence: Developmental periods

of

risk

for

dependence

upon

marijuana,

and

alcohol.

U

Neuropsychopharmacol. 26, 479-488.

cocaine,

N

Weiner, B., 1995. Judgments of responsibility: A foundation for a theory of social conduct. New

A

York, Guilford Press.

M

Wu, L.-T., Swartz, M.S., Brady, K.T., Hoyle, R.H., 2015. Perceived cannabis use norms and cannabis use among adolescents in the United States. J. Psych. Res. 64, 79-87.

D

Zebregs, S., van den Putte, B., Neijens, P., de Graaf, A., 2015. The differential impact of statistical

TE

and narrative evidence on beliefs, attitude, and intention: A meta-analysis. J. Health

A

CC

EP

Commun. 30, 282-289.

Figure Legends Figure 1. CONSORT Flow Diagram

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Figure 2. Standardized coefficients for the final mediation model (n = 263)

Figure 1.

Enrollment

Excluded (n=7)  Not meeting inclusion criteria (n=7)

M

A

N

U

Assessed for eligibility (n=484)

TE

D

Randomized (n= 477)

CC

EP

Allocated to Narrative video (n=234)  Received allocated intervention (n=234)  Did not receive allocated intervention (give reasons) (n=0)

A

Analysed (n=194)

 Excluded from analysis (took less than seven minutes or over three hours to complete the survey) (n= 49)

Allocated to non-narrative video (n=243)  Received allocated intervention (n=243)  Did not receive allocated intervention (give reasons) (n=0)

Analysed (n=202) • Excluded from analysis (took less than seven minutes or over three hours to complete the survey) (n=32)

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Figure 2.

Attitudes toward medical cannabis (R2 = .09)** .27 (.14)* a

Attitudes toward recreational cannabis (R2 = .41)***

.12 (.06) * 95% CI [.003, .27]

D

M

c’

-.14 (.14)NS

N

c

U

b

A

Narrative format (vs. expository format)

.44 (.06)***

A

CC

EP

TE

Note. * p < .05, *** p < .001. N.S. = p > .05; c path is the direct effect without mediator; c’ path is the indirect effect.

Table 1: Standard Deviations, Means and Bivariate Correlations of Background Variables Mean Std. 1 Deviat ion

1. Female 2. Liberal socioeconomic attitudes

0.53 4.93

0.50 1.91

3. Cannabis use

0.16

0.37

4. Cigarette use

1.26

1.72

5. MC attitudes, beliefs and intentions 5.34

1.13

6. Recreational cannabis attitudes, 3.43 beliefs and intentions

1.45

7. Narrative

0.52

0.50

8. Attribution

0.51

0.50

9. Stigma

0.50

3

4

5

6

7

8

1.000

0.403 1.000 ***

0.189 0.171 1.000 ** ** 0.508 0.299 0.427 1.00 *** *** *** 0

N

U

1.000 -0.067 1.00 0 -0.032 0.11 5 0.03 0.203 7 *** -0.034 0.10 1 0.14 0.191 1* *** -0.010 0.13 6* -0.15 0.01 6

0.054 0.140 0.03 0.068 * 7 0.002 0.068 0.056 0.01 9 0.007 0.00 0.042 0.041 1 0.005 0.06 3

A

M

D

A

CC

EP

TE

Note.*p <0.05, **p <0.01, ***p <0.001.

2

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Variables

0.50

1.00 0 1 0.00 1 0.0 0.00 14 8

Table 2: Results from Confirmatory Factor Analyses Attitudes, beliefs and intentions towards medical cannabis Fit indices 0.99

TLI

0.97

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CFI

RMSEA

0.07

Factor loadings Benefits outweigh risks

0.70

Cannabis can be helpful for people with specific illnesses

0.84 0.78

U

Empirical basis supports MC Fewer side effects

N

I would recommend to apply for MC license

0.77 0.71

M

A

MC should be in treatment 'basket'

0.75

Attitudes, beliefs and intentions towards recreational cannabis

D

Fit indices

TE

CFI TLI

Factor loadings

EP

RMSEA

CC

Cannabis use for all purposes should be legal

0.96 0.99 0.03

0.83 0.89

Usually people wo use cannabis recreationally enjoy it

0.57

A

Recreational cannabis use is normal part of life for some

I would use cannabis if a friend offered it

0.69

Using cannabis once or twice per week is not dangerous

0.75

Sale of cannabis to one adult to the next should be legal

0.50

I would be worried if a close friend used cannabis recreationally (reversed coded)

0.45

Table 3. Conditional indirect effect of narratives through MC attitudes, beliefs and intentions toward recreational cannabis attitudes, beliefs and intentions (n = 263) Predictors B SE t p 95% CI

14.838 3.484 0.284 1.035

<0.001 <0.001 0.776 0.302

4.204, 5.491 0.299, 1.078 -0.232, 0.310 -0.034, 0.109

0.202 0.045 0.167 0.135 0.198 0.273

1.811 2.328 -1.961 0.758 3.042 -2.953

0.071 0.021 0.051 0.449 0.003 0.003

-0.032, 0.762 0.016, 0.192 -0. 656, 0.001 -0.164, 0.369 0.212, 0.990 -1.346, -0.269

N

U

0.327 0.197 0.137 0.036

A

Constant 4.848 Format (1=Narrative) 0.689 Gender (1 = Female) 0.039 Liberal socioeconomic0.037 attitudes Recreational cannabis use 0.365 Cigarette use 0.104 Video quality -0.327 Stigma (1 = cancer) 0.102 Attribution (1= internal) 0.601 -0.807 Format X Attribution

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Mediator variable model (Attitudes, beliefs and intentions towards medical cannabis) R2 = 0.12, F(9,253) = 3.76, p < .0001

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Dependent variable model (Attitudes, beliefs and intentions towards recreational cannabis) R2 = 0.40, F(8,254) = 21.54, p < .0001

CC

EP

TE

D

Constant 0. 929 Format (1=Narrative) -0. 142 Gender (1 = Female) -0. 409 Liberal socioeconomic0. 040 attitudes Recreational cannabis use 1.639 Cigarette use 0. 024 Video quality 0. 055 Stigma (1 = cancer) -0. 171 0. 436 MC attitudes

0. 459 0. 144 0. 142 0. 038

2.024 -0. 988 -2.882 1.054

0.044 0. 324 0. 004 0. 293

0. 025, 1.831 -0. 426, 0. 141 -0. 689, 0. 130 -0. 034, 0. 113

0. 209 0. 046 0. 173 0. 139 0. 064

7.836 0. 526 0. 320 -1.230 6.867

<0.001 0. 599 0. 750 0. 220 <0.001

1.227, 2.051 -0. 066, 0. 114 -0. 285, 0. 395 -0. 446, 0. 103 0. 311, 0. 561

A

Conditional effects of MC attitudes, beliefs and intentions x Attribution (moderator) External 0.300 Internal -0.052 Index of moderated mediation

0.097 0.080

MC attitudes

0.123

-0.352

0.141, 0.530 -0.213, 0.106

-0.625, -0.137

A

CC

EP

TE

D

M

A

N

U

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Notes: Indirect effects tested with 5,000 bootstrap re-samples.