The use of e-cigarettes and other vaping devices among adolescents is an urgent public health problem due to the concern about adolescent exposure to nicotine. This study examined: (1) adolescents’ knowledge and beliefs about e-cigarette risks; and (2) whether knowledge and risk beliefs were associated with e-cigarette use. N = 69 adolescents completed a cross-sectional survey about e-cigarette knowledge, attitudes (i.e., risk beliefs), and behavior (KAB). Nearly half (47%) of the sample reported ever using e-cigarettes. The majority of adolescents knew about many of the risks of e-cigarettes, with no differences between never- and ever-users. However, risk beliefs, such as worrying about health risks of using e-cigarettes, varied across groups. Compared to never-users, e-cigarette ever-users were significantly less likely to worry about e-cigarette health risks, less likely to think that e-cigarettes would cause them negative health consequences, and less likely to believe that e-cigarette use would lead to addiction. In a multivariable logistic regression, prior combustible cigarette use, mother’s education, and addiction risk beliefs about e-cigarettes emerged as significant predictors of adolescents’ e-cigarette use. This study reveals that while knowledge is not associated with adolescent e-cigarette use, risk beliefs do predict use.

Evidence for the health harms of e-cigarettes is growing, yet little is known about which harms may be most impactful in health messaging. Our study sought to identify which harms tobacco product users were aware of and which most discouraged them from wanting to vape. Participants were a convenience sample of 1,872 U.S. adult e-cigarette-only users, cigarette-only smokers, and dual users recruited in August 2018. In an online survey, participants evaluated 40 e-cigarette harms from seven categories: chemical exposures, device explosions, addiction, cardiovascular harm, respiratory harm, e-liquid toxicity, and other harms. Outcomes were awareness of the harms (“check all that apply”) and the extent to which the harms discouraged vaping (5-point scale; (1) “not at all” to (5) “very much”). Awareness of most e-cigarette harms was modest, being highest for harms in the device explosions category of harms (44%) and lowest for the e-liquid toxicity category (16%). The harms with the highest mean discouragement from wanting to vape were the respiratory harm (M = 3.82) and exposure to chemicals (M = 3.68) categories. Harms in the addiction category were the least discouraging (M = 2.83) compared with other harms (all p < .001). Findings were similar for e-cigarette-only users, cigarette-only smokers, and dual users. Addiction was the least motivating e-cigarette harm, a notable finding given that the current FDA e-cigarette health warning communicates only about nicotine addiction. The next generation of e-cigarette health warnings and communication campaigns should highlight other harms, especially respiratory harms and the chemical exposures that may lead to health consequences. E-cigarette health harms related to respiratory effects, chemical exposures, and other health areas most discouraged vaping among tobacco users. In contrast, health harms about addiction least discouraged use. Several countries have begun implementing e-cigarette health warnings, including the United States, and many others are considering adopting similar policies. To increase impact, future warnings and other health communication efforts should communicate about health harms beyond addiction, such as the effects of e-cigarette use on respiratory health. Such efforts should communicate that e-cigarette use is risky and may pose less overall risk to human health than smoking, according to current evidence.

Pictorial warnings on cigarette packs motivate smokers to quit, and yet the warnings’ theoretical mechanisms are not clearly understood. To clarify the role that risk appraisals play in pictorial warnings’ impacts, we conducted a meta-analysis of the experimental literature. We meta-analyzed 57 studies, conducted in 13 countries, with a cumulative N of 42,854. Pictorial warnings elicited greater cognitive elaboration (e.g., thinking about the risks of smoking; d = 1.27; p < .001) than text-only warnings. Pictorial warnings also elicited more fear and other negative affect (d = .60; p < .001). In contrast, pictorial warnings had no impact on perceived likelihood of harm (d = .03; p = .064), perceived severity (d = .16; p = .244), or experiential risk (d = .06; p = .449). Thus, while pictorial warnings increase affective and some cognitive risk appraisals, they do not increase beliefs about disease risk. We discuss the role of negative affect in warning effectiveness and the implications for image selection and warning implementation.

Perceived message effectiveness (PME) is commonly used in health communication research and practice, yet there has been a dearth of studies comparing different operationalizations of the PME construct. In the present study, we compared the two major types of PME – message perceptions and effects perceptions – among N = 557 young adults. Participants were randomized to one of two conditions: 1) The Real Cost e-cigarette prevention ads developed by the Food and Drug Administration (FDA condition) or 2) information-only e-cigarette control ads developed by the Mayo Clinic (control ad condition). Study predictors were message and effects perceptions measures and actual message effectiveness (AME) outcomes were risk beliefs about vaping and intentions to vape. Results showed that both message perceptions (M = 3.82 vs M = 3.29; p < .001) and effects perceptions (M = 4.13 vs M = 3.82; p < .001) were higher in the FDA ad condition compared to control. Risk beliefs about vaping were also higher in the FDA ad condition than control (M = 3.95 vs M = 3.79; p =.022), but we found no differences in participants’ intentions to vape, which were low overall (M = 1.59 in FDA vs M = 1.58 in control). In multivariate analyses adjusting for covariates and including both types of PME, only effects perceptions (not message perceptions) were associated with risk beliefs about vaping (b =.37, p < .001) and intentions to vape (b = −.26, p < .001). Our findings advance PME research by demonstrating the differing nature of message and effects perceptions, and suggest that effects perceptions should be utilized during message pretesting.

Adolescent vaping remains a problem in the United States, yet little is known about what health warning themes most discourage vaping among adolescents. We sought to identify the most compelling themes for vaping warnings for US adolescents. Participants were a national probability sample of 623 US adolescents aged 13–17 years, recruited in the summer of 2020. Adolescents were randomized to one of the five warning message themes about the potential health effects of vaping: 1. chemical harms, 2. lung harms, 3. Coronavirus Disease 2019 (COVID-19) harms, 4. nicotine addiction, or 5. control (messages about vape litter). The primary outcome was perceived message effectiveness (PME; 3-item scale). Secondary outcomes were negative affect (fear), attention, anticipated social interactions, and message novelty. Adolescents rated the chemical, lung, and COVID-19 harms warning messages higher on PME than nicotine addiction and control (all p < .05), while nicotine addiction was rated higher than control (p < .05). The chemical, lung, and COVID-19 harms warning themes also elicited greater negative affect than nicotine addiction and control (all p < .05). For all other secondary outcomes, the COVID-19 harms warning message theme was rated higher than nicotine addiction and control (all p < .05). Adolescents perceived warning message themes about lung, chemical and COVID-19 health effects of vaping as more effective than nicotine addiction. To discourage vaping, the FDA and others should communicate to youth about the health effects of vaping beyond nicotine addiction. Adolescents rated warning message themes about the lung, chemical, and COVID-19 health effects of vaping as more effective than nicotine addiction, while nicotine addiction was rated as more effective than control themes about vaping litter. To discourage vaping among adolescents, health messaging should expand message themes to communicate about a broader set of health effects of vaping beyond nicotine addiction.