Introduction

The 2016 U.S. Surgeon General’s report [1] raised serious concerns about adolescents’ use of e-cigarettes, also known as vapes, vape pens, vaporizers, mods, and tank systems [1]. In national surveys, use of e-cigarettes at least once in the past 30 days among middle- and high-school students was higher (6.2% and 12.5%, respectively) than for use of cigarettes (2.6% and 10.5%) or any other tobacco product [2]. The higher prevalence of e-cigarette use among adolescents may be due in part to more favorable attitudes towards e-cigarettes compared to cigarettes [3–5]. Studies of e-cigarette-related attitudes and perceptions show that adolescents hold more favorable attitudes toward and attribute fewer health and social risks to e-cigarettes compared to other tobacco products [5–8], and that those who have used e-cigarettes hold more positive attitudes towards e-cigarettes [6,9].

People are more likely to be willing to smoke and to actually smoke if they hold more positive mental images or prototypes of a typical smoker [10–14]. Among adolescents who have never smoked, positive prototypes (e.g., cool, sociable, and intelligent) are associated with greater susceptibility to smoke, and those who report having a self-image similar to that of their reported smoker-image (“prototype”) are almost twice as likely to report smoking uptake one year later [10,15]. Positive appraisals of smokers are influenced by best friend’s smoking, outweigh weaker parental antismoking expectations, and lead to greater smoking intentions [16]. Some evidence also suggests that cigarette smoker prototypes are related to e-cigarette use, and that among nonsmoking adolescents who held negative beliefs about a typical smoker, those with scores above the median (compared to those at or below the median score) are less likely to report willingness to try e-cigarettes (24% vs. 12%, p = .02) [17].

While ample evidence shows that cigarette smoker prototypes are associated with cigarette use intentions and behaviors [10–16], little research has explored e-cigarette user prototypes among adolescents. Such knowledge is important because messages aimed at countering positive imagery and glamorous portrayals of e-cigarette users could be a promising approach to preventing adolescent e-cigarette use. Our study sought to characterize adolescents’ prototypes of adolescent e-cigarette users and to determine whether these prototypes are related to willingness to use e-cigarettes and actual e-cigarette use [17]. We hypothesized that adolescents who are willing to try e-cigarettes or have used them in the past will hold more positive opinions of e-cigarette users than those who are unwilling to use or have never used them.

Methods

Results

Opinions of adolescent e-cigarette users

Participants’ overall opinion toward the typical adolescent e-cigarette user was somewhat negative, with an average score of 2.23 out of 5 (between “somewhat negative” and “neutral”) (Table 1). The majority (61%) of participants indicated somewhat or very negative overall opinions of e-cigarette users (Fig 1). Only 4% of participants had either somewhat or very positive overall opinions of adolescent e-cigarette users. Participants not willing to try e-cigarettes and never users of e-cigarettes reported more negative overall opinions than adolescents who were willing to try or who had used e-cigarettes (p < .001; Table 1).

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Fig 1. Overall opinions toward adolescent E-cigarette users (n = 578).

https://doi.org/10.1371/journal.pone.0206352.g001

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Table 1. Mean (SD) overall, positive, and negative opinions toward adolescent E-cigarette users, for full sample and separately for those not willing and willing to try E-cigarettes, and for never and ever users of E-cigarettes.

https://doi.org/10.1371/journal.pone.0206352.t001

When asked to consider only their positive or negative opinions, adolescents reported weaker positive opinions (mean 1.67 on a unipolar response scale coded as 1 to 4) than negative opinions (mean 2.65) (Table 1). Almost 90% of the sample reported opinions about adolescent e-cigarette users that were not at all positive or only slightly so, and 59% reported opinions about e-cigarette users that were quite a bit or extremely negative (Fig 2). Those not willing to try e-cigarettes and never-users of e-cigarettes reported weaker positive opinions and stronger negative opinions regarding adolescent e-cigarette users than those who were willing to try or had ever used e-cigarettes (Table 1).

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Fig 2. Positive and negative opinions about adolescent E-cigarette users (n = 578).

https://doi.org/10.1371/journal.pone.0206352.g002

Prototypes of adolescent e-cigarette users

Participants infrequently described adolescent e-cigarette users using positive traits (sexy, cool, clean, smart, and healthy). Positive traits received ratings of “not at all” to “somewhat” on average (means ranged from 1.30 to 1.68; Table 2). Endorsement of positive traits was stronger among adolescents who were willing to try or had used e-cigarettes in the past than those unwilling to try and who never used e-cigarettes (all p < .01). In contrast, participants sometimes described adolescent e-cigarette users using negative traits (unattractive, trashy, immature, disgusting, and inconsiderate). Negative traits received ratings of “a little bit” to “somewhat” on average (means ranged from 2.74 to 3.02; Table 2). Endorsement of negative traits was stronger among adolescents unwilling to try and never users of e-cigarettes than those who were willing to try or had used e-cigarettes (all p < .01).

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Table 2. Mean (SD) traits ascribed to adolescent E-cigarette users, by full sample, by not willing and willing to try E-cigarettes, and by never and ever users of E-cigarettes.

https://doi.org/10.1371/journal.pone.0206352.t002

Discussion

Numerous studies have described prototypes of cigarette smokers held by adolescents, with more positive images associated with greater likelihood of cigarette use.[10–16] In our study, we extended these findings to examine images of e-cigarette users held by adolescents. Participants reported “somewhat negative” overall opinions of adolescent e-cigarette users, on average. When asked separately about negative and positive opinions, adolescents rated their opinions about e-cigarette users, on average, as “quite a bit” negative and “slightly” positive. Also, the traits unattractive, trashy, immature, disgusting, and inconsiderate received ratings of “somewhat” attributable to adolescent e-cigarette users, on average, while the traits sexy and cool received ratings of “not at all” attributable; and clean, smart, and healthy were “a little bit” attributable. These findings do not support our hypothesis that participants would harbor positive images of adolescent e-cigarette users, which we surmised based on the increase in e-cigarette use over the past few years, perceptions that e-cigarettes are less harmful than other tobacco products, and concerns that e-cigarettes are becoming more socially acceptable [5,7,8,20].

Our findings support our hypothesis that participants who were willing to try e-cigarettes or who had already done so would have more positive prototypes and would hold more positive opinions and images of youth who use e-cigarettes. Research on smoker prototypes and willingness has shown that the more positively the prototypical smoker is seen, the more willing children and adolescents are to smoke [13,21]. Our findings supported our hypothesis that prototypes are associated with past e-cigarette use. Other research has shown that opinions and images may change to support the behavior, once begun [14,22]. We could not determine such relationships with our cross-sectional data; future study should examine these prospective relationships.

Evidence shows pervasive marketing of e-cigarettes targets adolescents by including attractive models, appealing flavors, and claims of lower harm [23–27], which can lead to formation of positive images of people who use e-cigarettes [28–31]. However, our findings suggest these messages have not translated to positive images of e-cigarette users among this group of adolescents. It is important to ensure that adolescents do not formulate “cool” or otherwise desirable images of e-cigarette users, as these images could become established, as occurred with the positive cigarette-smoking prototypes, which took decades of concentrated efforts to dispel [32]. Since most children begin and adolescents continue to build their prototypes based on what they see in mass media, prevention efforts could include media campaigns that counteract creation of positive imagery by increasing adolescents’ intentions to protect themselves from harm and could include highlighting negative health effects of e-cigarettes and deceptive e-cigarette marketing strategies employed by the tobacco industry [33–36].

Study limitations include use of a convenience sample of high school students in California who may not generalize to other populations; for example, in places where prevalence of adolescent e-cigarette use is much higher, adolescents may hold more positive opinions and have more positive images. The cross-sectional nature of the study did not allow us to determine whether the prototypes drive behavior or vice versa. Longitudinal studies should prospectively examine whether prototypes at baseline predict behavior at follow-up, and intervention studies could attempt to manipulate prototypes to change tobacco use behavior. The data were collected in 2015–2016, before the rise of popularity in JUUL electronic cigarettes [37]. Nonetheless, these findings are useful for the purpose of historical comparisons and for potentially understanding the current context of e-cigarette use. For example, future studies might examine how user prototypes have changed with the rise of JUUL.

In this study we did not differentiate between perceptions of adolescents who use e-cigarettes with or without nicotine. While many adolescents report that they vape non-nicotine substances (i.e., “just flavors”) [38] adolescents who self-report using e-cigarettes without nicotine have less knowledge about e-cigarettes, indicating they might not be correctly understanding and reporting their nicotine [39]. Furthermore, a recent chemical analysis of e-cigarettes confiscated in Arizona schools showed that nearly 80% of them contained nicotine, and 57% contained very high levels of nicotine (over 44 mg/mL) [Mansur, E. 2018. E-Liquid Lab Testing and School Resource Officer Outreach in Arizona. Presented at the Public Health Law Center Webinar “What’s the hype? JUUL electronic cigarette’s popularity with youth & young adults.” Available at http://www.publichealthlawcenter.org/webinar/what%E2%80%99s-hype-juul-electronic-cigarette%E2%80%99s-popularity-youth-young-adults)]. Thus, adolescents are frequently incorrect in their assessment of the nicotine content of the substance they are vaping. Future studies should evaluate whether adolescents’ opinions of vapers differ depending on the substance they are vaping.

Our study found that adolescents typically have negative opinions about and images of adolescents their age who use e-cigarettes. However, adolescents who were willing to use e-cigarettes or who reported already having used e-cigarettes held more positive opinions about and images of vapers their age. These findings suggest promising avenues for reducing e-cigarette use could include monitoring prototypes, restricting advertising that leads to more positive prototypes, and developing public health messaging campaigns that counter positive images and reinforce negative opinions without directly stigmatizing the users (perhaps by revealing industry involvement) [1]. A challenge for communication campaigns is as the e-cigarette marketplace grows and changes so will opinions and images of e-cigarette (and other tobacco products) users. Ongoing research can help public health efforts be attuned to changes in opinions, and longitudinal studies should prospectively examine whether prototypes predict later tobacco use behavior. Regulatory efforts that deal with perceptions of e-cigarette users can also be informed by past tobacco efforts and research that dealt with perceptions of cigarette smokers in the media [40–42]. Clinicians can play an important role by keeping apprised of what type of e-cigarettes their adolescent patients are using, how patients who are non-users view those who use e-cigarettes, and by providing accurate information on the health-effects of e-cigarettes to support existing negative images and to dissuade further use and positive image development. In sum, although it is encouraging that many adolescents already hold somewhat negative beliefs about adolescents who use e-cigarettes, more can be done with this information to prevent initiation or encourage cessation of e-cigarette use.