In recent years, e-cigarettes have gradually become popular in various countries. These devices, which produce aerosols by heating a liquid containing a variety of chemicals such as nicotine, additives, and flavorings, have become increasingly popular among young people, with the number of e-cigarette users in this demographic having grown rapidly in recent times.
The Sixth Conference of the Parties to the World Health Organization Framework Convention on Tobacco Control report detailed that the global expenditure on e-cigarettes was USD 3 billion in 2013. Without considering trends towards banning them, e-cigarette sales are expected to increase by 17 times by 2030 
, with the e-cigarette industry predicted to become one of the eight major global industries 
. China’s e-cigarette industry is also growing rapidly. By 2020, the national penetration rate of e-cigarette users reached 1% 
, with sales of more than USD 20 billion recorded, as the marketing of small smoke products with bullet replacements became mainstream. According to data from the Chinese Center for Disease Control and Prevention, the e-cigarette use groups in 2018 were dominated by young people, with 1.5% of e-cigarette users being people aged 15–24 years old, and the proportion of those who had heard of or used e-cigarettes and were now using them having increased compared with 2015. In 2019, youth e-cigarette users in China increased to 2.7%, with 3.55 million people having been added that year 
Early e-cigarette products were marketed as smoking cessation products and were supported by some tobacco control organizations because they followed the global political trend of tobacco control 
. Thus, the “alternative” value of e-cigarettes has been the focus of scientific studies. Previous studies examining people’s level of dependence on cigarettes and e-cigarettes have reported a tendency for the two types of dependence to alternate, i.e., to ebb and flow 
, thus confirming the alternative value of e-cigarettes with regards to cigarette cessation 
. Such studies are also taking place in China; these have examined the health risks, development trends, market supply and demand, and regulatory measures of e-cigarettes based on their alternative value 
. Recently, some scholars have used Machine Learning and Artificial Intelligence to further examine usage behavior 
. In addition, recent emphasis on the addictive, social, and flavor appeal aspects of e-cigarettes has framed the devices as a new tool for fashionable socialization 
. This means that, for e-cigarettes, portrayed marketing terms and familiar usage environments also lead to the generation and transmission of usage behavior.
2. Scientific Discussion for E-Cigarettes
2.1. An Alternative or Not?
One of the main differences between e-cigarettes and tobacco lies in their safety of use. How are e-cigarettes a safer alternative to smoking? Their safety is demonstrated firstly in their inhibition and reduction of combustion, which studies have proven to be one of the leading causes of tobacco-related morbidity and mortality 
, and secondly in their reduction of the environmental nuisance caused by second- or third-hand smoke. As e-cigarettes produce less toxic vapor than smoke from combustible cigarettes 
, some scholars consider them as being relatively less harmful to health than tobacco 
Another difference is that e-cigarettes function as an alternative to tobacco during smoking cessation. The relatively low risk of e-cigarettes makes them an essential aid in quitting smoking. They are the most popular method of quitting in the United Kingdom and the United States 
. The health concerns of tobacco (nicotine) addiction are of great concern 
and can lead to physiological and psychological problems. Physiologically, nicotine increases dopamine, produces adrenaline and blood glucose, and for a short time, brings pleasure, increases concentration, reduces appetite, and increases energy, but this good state does not last; a bad mood returns, followed by a greater craving for pleasure, which leads to the vicious cycle of tobacco addiction 
. When an addictive substance is used repeatedly, tolerance to the substance gradually develops, which leads to demand for higher quantities of the substance in order to achieve the same effect 
. Regarding the multidimensional and complex self-control of tobacco addiction, prevention, treatment, and cessation are of great concern 
. Compared to other ways of quitting, e-cigarettes offer a pleasant alternative to smoking that can meet the needs of smokers by replacing the physical, psychological, social, cultural, and identity-related aspects of addiction 
However, the alternative effects of e-cigarettes are still worthy of deeper investigation. Studies have found secondary effects, such as smoking relapse, dual use, and priming effects in e-cigarette users 
. Meanwhile, opponents argue that e-cigarettes and traditional cigarettes do not have a causal relationship, and that the temporary, linear channel between them is interfered with by other factors. Further, they argue that e-cigarette and traditional cigarette use behaviors are understood as sequential connections, and that these behaviors are part of a complex holistic process that also includes risk behaviors, consumption, and a variety of social complexities (gender, race, class) that cannot be reduced to individual components 
As a new tobacco and recreational product, e-cigarettes have revolutionized traditional smoking behavior with their unlit, portable, and flavorful features. The use of e-cigarettes is rich in connotations, both as a form of smoking cessation and as a new form of smoking behavior, which stems from the cross-cutting attribute of e-cigarettes’ being understood as both “cigarettes” and different from “traditional tobacco.” As the number of e-cigarette users increases globally, the social implications of e-cigarette use must be taken into account. From an e-cigarette user’s perspective, how are e-cigarettes viewed, and do they have alternative uses, dual uses, and introductory effects? How do e-cigarette users understand e-cigarette behavior in their daily lives?
2.2. Risk for Adolescents: Flavoring
As individuals enter adolescence, along with experiencing the awakening and strengthening of self-awareness, they can become susceptible to the influence of peers, popular culture, and fashion discourse, and can develop health-hazardous behaviors, such as e-cigarette use 
. A total of 3.6 million young Americans used e-cigarettes in 2018, and this figure rose to 5 million in 2019 
. In 2022, the Annual National Youth Tobacco Survey, which focused on middle and high school students, found that more than 2.5 million U.S. students currently used e-cigarettes. Meanwhile, recent data from the Chinese Center for Disease Control and Prevention reported that young people had an e-cigarette usage rate of 1.5% in 2018 in China. By 2021, young people’s usage rate had reached 2.5%, which was higher than that of 1.6% among adults, a finding which has also been supported in recent empirical studies 
Research on youth e-cigarette use behavior has first focused on the causal factors leading to e-cigarette use, specifically the peer effect 
, social attributes, and curiosity drive. The peer effect refers to e-cigarette use that is influenced by friends, classmates, and family members 
; following and imitating are the main behavioral factors of e-cigarette use in the context of peer relationships. Closely related to peer influence, the social uses of e-cigarettes relate to their use in a broader sense, with e-cigarette features such as their providing freedom from smoke-free environments and transmission sharing 
reinforcing connections among young users in specific settings. The curiosity-driven psychological factor relates to the value of e-cigarettes as a fashionable entertainment and lifestyle exhibition tool, providing a subcultural lifestyle that satisfies young people 
. However, this kind of psychological motivation is vulnerable to the manipulation of e-cigarette suppliers, and supply advertising can enhance the e-cigarette acceptance of young people through the use of attractive photos, videos, and text on online platforms where youth gather 
Second, the influences of the technology, taste and decorative features of e-cigarettes can be explained from a developmental and objective perspective. E-cigarette technology has evolved through four generations to achieve more powerful features and to feature adaptive flavors. The current fourth generation of e-cigarettes, the pod-style e-cigarette (pod system), has gained new highs in the number of young users due to, among other factors, its portability due to its low weight, improved oil leakage, and lower manufacturing costs and prices (USD 43−46 in the Chinese market) 
. The adaptability of e-cigarette flavors avoids the olfactory irritation and tarry taste of smoking traditional cigarettes and is dedicated to a pleasant sensory experience for users while suppressing the aversive effects of nicotine 
. Worryingly, the presence of flavor, while masking the irritation of traditional cigarette use, can likewise reduce the body’s immediate perception of harm. For instance, Pepper 
and other scholars found that American adolescents preferred to try menthol-, fruit-, and candy-flavored e-cigarettes, a preference that led to almost six times the interest in trying fruit flavored e-cigarettes compared to tobacco-flavored e-cigarettes, which fuelled e-cigarette use (this preference was discovered also in Jongenelis’ study 
). Finally, the decorative features of e-cigarettes also appeal to young people. Featuring shapes full of design elements that support personalized design, such as protective cases and decorations, e-cigarette devices reinforce their users’ desire to purchase e-cigarette products 
Therefore, researchers have grown concerned that e-cigarettes can trigger more complex negative effects than traditional cigarettes. First, adolescents and young adults do not have a clear understanding of the hazards of e-cigarettes and only perceive them to be less harmful than traditional cigarettes 
, which could lead to physical dangers for users. Second, people who have tried e-cigarettes are more likely to use traditional cigarettes, given the “introductory effect” of e-cigarettes 
. A meta-analysis of 91,051 adolescent subjects showed that the risk of adolescents using e-cigarettes and then using traditional cigarettes was 2.21 times higher than the risk of “never using e-cigarettes” 
. Therefore, it is likely that e-cigarette addiction will occur before a user quits traditional cigarettes 
. Based on this perception, some regions and countries have controlled the sale and use of e-cigarettes by improving state laws, regulating sales, and publishing the hazards of e-cigarette ingredients 
3. Conclusion from Empirical Studies
The main contributions of this research, regarding both current theoretical and empirical research developments, include the following three points: Firstly, it enriches the perception of e-cigarettes at the public awareness level and offers insights from the Chinese context. For instance, in this context, it found that e-cigarettes are perceived by some youth users as snacks, and that e-cigarette use behavior is considered recreational. However, the hermeneutic view of recreational use is relatively macro and holistic. Both recreational and medical drug use is discussed in drug research, which enriches discussions surrounding drug practice and decriminalization from a drug user’s perspective. However, in this research, e-cigarette users were not found to exhibit non-recreational use behaviors. Therefore, instead of generalizing the view of e-cigarettes as being used recreationally, the perceptions of and definitions used by e-cigarette users should be further explored. Further, the emergence of the snack attribute of e-cigarettes dynamically and vividly describes the behavior of e-cigarette use in daily life as a “habitual desire to use but accompanied by intermittent aversion, readily adjusting the dose and time of use, and occasionally quitting when aware of health risks.”
Secondly, two correlated models are provided that assess youth perceptions and behaviors surrounding e-cigarette use. Considering the models in combination is sufficient to explain “why some youth use e-cigarettes and believe addiction is manageable despite knowledge of the harms.” These models consider both social and individual perspectives and assess both external and internal motivations. Further, they assist in capturing empirical knowledge using analytical techniques, and also assist social workers in frontline addiction to understand and grasp the causes of behavior changes in e-cigarette users. Through exploring external motivations, this research analyzed the contextual pathways of social forces and their combined consequences. Thus, researchers described adolescents as being at a “crossroads” of multiple connections, with this linkage formulation being similar to Hughes’ multilinear connections perspective 
. Researchers acknowledge the existence of multiple, multidirectional, and multilinear connections between the various “elements” of the e-cigarette user worthy of study and that practice forms part of an entire complex process. However, the multiple connections revealed by Hughes break through the double-chain single-line “channel” thinking of the Gateway, thus helping us avoid falling into inconvenient and vain metaphysical logic. Researchers using this concept need to organically combine and logically present all possible elements in order to provide a convenient tool for exploring causes and analyzing effects. The analytical processing that occurs on top of these connections leads to the emergence of combinatorial models.
Having a core focus on “how individuals make their logical trade-offs and decisions under the influence of social forces,” the internal motivation model explores six judgment conditions and considers the psychological process of young users’ guided behavior under different experiences and events. The model attempts to frame the decision-making and trade-off processes of e-cigarette users as forming a comprehensive and holistic set of conditions, therefore providing relatively complete and complex insights compared to some models that start with a single condition. In the user narratives, researchers also focused on the preferred meanings of different conditions for individuals, which helps to explain why seemingly illogical behaviors occur in situations where conditions present relative conflicts, such as confidence use behavior and controlled addiction prediction in youth experiencing harm.
Finally, unlike adolescent users, young adult users are free from the dual control of family and school and face a more complex social situation and more accessible standards of judgment. The concept of the crossroads situation is close to these users’ real life situation, in which they have no strong direct supervisors (e.g., parents and teachers in youth studies). These users need to grasp the consequences of e-cigarette use on their own, which are impacted by the integrated and complex dimensions of culture, policy, medicine, and socialization. In addition, instead of just experiencing the motive of temptation, young adults’ motives for e-cigarette use involve six critical perspectives, and these users possess the decision-making ability to choose to actively use or not use e-cigarettes. The study of young adults therefore provides rich insights on the experiences and differential thinking of this demographic.