Subjective experiences of the addictive potential of E-cigarettes: results from focus group discussions

Abstract

Background

Electronic cigarettes (e-cigarettes) have specific properties, such as their taste, vapor, or technicality, which might facilitate experiences of addiction. In this study, we aimed to investigate the subjective experience of the addictive potential of e-cigarettes using qualitative methodology.

Method

We conducted semi-structured focus groups with adult e-cigarette users to discuss subjective experiences of addiction. Informed by Braun and Clarke’s approach to thematic analysis, we conducted a deductive-inductive analysis in MAXQDA. First, deductive codes were based on the 10 domains of e-cigarette addiction previously identified by Bold and colleagues. Second, we inductively coded those e-cigarette properties that were identified by users to have addictive potential.

Results

We conducted five focus group discussions with a total of 14 e-cigarette users (8 male, 6 female). Subjective experiences of e-cigarette addiction discussed by focus group participants accorded with domains of e-cigarette addiction as defined by Bold and colleagues. For example, users reported automatic use, craving, or sensory dependence. The only domains not reported were preference over competing rewards and impaired control. Second, we inductively identified three central properties of the addictive potential of e-cigarettes: unlimited usability, unobtrusiveness, and pleasant taste.

Conclusion

Our findings were summarized in the Model of the Addictive Potential of E-cigarettes (MAPE). Understanding which e-cigarette properties lead to subjective experiences of addiction can inform cessation programs for those who want to quit as well as the refinement of measures to assess e-cigarette addiction.

Keywords:

• E-cigarettes
• addiction
• qualitative research
• vaping
• focus group

Introduction

Electronic cigarettes (e-cigarettes) are battery-powered devices that produce an aerosol by heating a liquid usually containing nicotine and flavors, which is then inhaled by the user (WHO 2021). Although e-cigarettes are generally considered less harmful than tobacco cigarettes, they still pose health risks, particularly for nonsmokers and younger populations (McNeill et al. 2022; National Academies of Sciences and Medicine 2018). While e-cigarettes have been found to aid smoking cessation, those who use them to quit smoking tend to remain longer-term e-cigarette users (Hartmann-Boyce et al. 2021). In line with this, a recent randomized controlled trial found that e-cigarette use led to a reduction in cigarette dependence but an increase in e-cigarette dependence in smokers using e-cigarettes for smoking reduction (Yingst et al. 2022). Furthermore, longitudinal studies found an association between e-cigarette use and subsequent smoking initiation, especially among young nonsmokers (O’Brien et al. 2021). However, a number of methodological limitations preclude an interpretation of this association as causal (Chan et al. 2021). The studies discussed above highlight that understanding the addictive potential of e-cigarettes is crucial to aid cessation and prevent smoking initiation, and thereby mitigating long-term public health risks.

E-cigarettes have unique qualities such as various flavors, customizable nicotine levels, and electronic adjustment options to manipulate nicotine delivery, which may result in substantially different addictive potential compared to tobacco cigarettes (Farsalinos et al. 2013; Kim et al. 2016). Research has indeed shown that e-cigarettes are associated with addictive symptoms, with studies finding notable levels of nicotine dependence among e-cigarette users (Morean et al. 2018; Lohner et al. 2023). However, users tend to perceive e-cigarettes as less addictive than tobacco cigarettes (Lohner et al. 2023).

In a previous study in the context of the EVAPE (EValuation of the Addictive Potential of E-cigarettes) project, our netnographic analysis of e-cigarette online forums revealed that users discuss addiction symptoms such as craving, excessive vaping, and use despite health problems (Szafran et al. 2023). However, not all symptoms of tobacco use disorder, as defined by the DSM-5 (American Psychiatric Association 2013), apply to e-cigarette use: symptoms such as hazardous use, neglecting responsibilities, restriction of social activities, and loss of control were reported by few users, if at all. Furthermore, many users reported an absence of typical addiction symptoms, such as withdrawal. This indicates the need for a more detailed investigation of symptoms of addiction to e-cigarettes. Consequently, we designed a qualitative study, informed by the 10 domains of e-cigarette addiction identified in a previous study by Bold et al. (2018), to examine the experience of addictive symptoms in focus groups with e-cigarette users.

Methods

The methods used in this study were published beforehand (Vollstädt-Klein et al. 2021) and approved by the Medical Ethics Committee of the Medical Faculty Mannheim of the University of Heidelberg (2017-567-N-MA). The methodology and results are reported according to the Consolidated Criteria for Reporting Qualitative Research (COREQ) (Tong et al. 2007). We recruited adult e-cigarette users living in Germany. To be eligible, e-cigarette users had to be exclusive users of nicotine-containing e-cigarettes with no concomitant use of other tobacco products (i.e. no dual use). In addition, e-cigarettes had to be used daily, irrespective of the duration of vaping by the users. We used the following recruitment strategies: (1) online advertisements on Facebook and e-cigarette online forums, (2) leaflets in local e-cigarette shops, bars, kiosks, and restaurants, (3) announcements on the faculty staff e-mail list of the Medical Faculty Mannheim of Heidelberg University, and (4) snowballing. For reimbursement, we offered participants 50€ by bank transfer. To reach a certain diversity in age, gender, and geographic location, we held focus groups on site and online. Recruitment was stopped after five focus groups as the study team agreed that data saturation was reached.

Data collection

Focus group discussions were held in rooms of Heidelberg University and online via a videoconferencing system between June and December 2022. One researcher with formal training in conducting focus groups (MA) moderated the focus groups following a pre-conceptualized discussion guide (see Appendix A). We developed the discussion guide based on our previous research (Lohner et al. 2023; Szafran et al. 2023). The guide included semi-structured questions as well as one interactive task (see Appendix A). A second team member (NW or DS) accompanied the discussions to keep time and take notes. Participants signed a consent form before the beginning of the discussion and filled in a demographic questionnaire afterward. Overall, the sessions lasted 90 min each. Focus groups were audio-recorded and transcribed verbatim.

Data analysis

After transcription, the data was analyzed based on Braun and Clarkes’ (2006) approach to thematic analysis. The 10 domains of e-cigarette addiction proposed by Bold et al. (2018) in their overview of e-cigarette addiction based on expert views guided our deductive analysis (for an overview see Table 1). Two authors (MA, NW) independently coded each focus group discussion with the software MAXQDA (VERBI Software 2022). Agreement between the authors was then tested using MAXQDA’s tool for intercoder agreement, with 76% agreement between authors, indicating substantial intercoder agreement. The authors discussed disagreements and, in case a solution could not be found, a third author (SS) was consulted. Quotes chosen for display in the paper were translated with forward-backward translation by two authors (MA, NG). Finally, we used inductive thematic analysis to identify e-cigarette properties facilitating addiction.

Table 1. Definition of themes guiding the deductive analysis based on Bold et al.’s (2018) domains of e-cigarette addiction.

Theme	Description
Quantity and frequency of use	Reports of frequent e-cigarette use, high duration of use, or when excessive use is perceived as a problem.
Tolerance	Reports about tolerance development, e.g. lack of nicotine flash or increase of nicotine dose to feel effect.
Perceived benefits	Reports that vaping helps when feeling down or just puts users in a good mood. Reports of vaping to help with concentration.
Withdrawal symptoms	Description of physiological and psychological withdrawal symptoms, for example, restlessness, irritability, difficulty concentrating, sweating, trembling, or palpitations, when not vaping for a longer period or when using e-cigarettes with lower nicotine doses.
Craving/urge to use	Description of the desire to use e-cigarettes or frequent thoughts about it, e.g. when other people vape nearby, in the morning after getting up, when forgetting the e-cigarette at home, or in situations where e-cigarette use is forbidden. In addition, in the context of habits that one cannot give up, for example, vaping when drinking alcohol.
Use despite harm	Physical Harm: Report of consumption in situations in which physical danger can be assumed. Health risks: Report of continued use despite negative health effects or knowledge of health risks (both physical and psychological). Social risks: Report of continued use despite disapproval or conflict with friends, colleagues or family.
Impaired control	Reports of unsuccessful attempts to stop, reduce, or keep e-cigarette use or nicotine level constant.
Automaticity	Reports of habitual e-cigarette use, e-cigarette use without thinking about it or making a deliberate decision to vape, not realizing the e-cigarette use while vaping.
Preferred over competing rewards	Reports that activities are avoided if vaping is not possible (e.g. going to the cinema, train ride), and other rewards are foregone for e-cigarette use.
Sensory dependence	Reports about enjoying vaping, or the smell, feeling or other aspects of e-cigarette use.

Results

Participant characteristics

We conducted five focus groups, two of which were held online. A total of 14 current e-cigarette users from all over Germany (8 male, 6 female) participated in the focus groups (between 2 and 5 participants per group). The median age was 38 years with a range from 18 to 64 years. All participants reported daily e-cigarette use with nicotine-containing liquids, with a majority vaping liquid containing lower doses of nicotine (2 mg to 5 mg). No participant reported the use of tobacco products at the time of the study. All participants had smoked tobacco cigarettes before their switch to e-cigarettes. The majority of participants had started vaping in the last five years, with only two reporting use for more than 10 years. Most users stated that the fear of the negative health consequences of tobacco cigarette smoking led to their switch to e-cigarettes. A few also said that cost reduction and the pleasant taste of e-cigarettes were a reason for them to switch. Some participants had switched to e-cigarettes with the intention of stopping nicotine consumption overall.

Results of the deductive analysis

Below, our results for each code are listed. Information in square brackets was added for better comprehension of the quotes.

Quantity and frequency of use

Participants reported using their e-cigarettes frequently, in different situations and often without stopping. For example, participant 2.1 (male, 29) reported: ‘I vape permanently. So the e-cigarette is almost never put away.’ One reason for the high frequency of use seemed to be that, because of their pleasant smell, users vaped at home or in their cars: ‘I cannot say how often it [the use] is now. And above all, what I do now is what many others no longer do - many no longer smoke [tobacco] in the apartment. I vape at home’ (participant 3.1, female, 60). Some participants saw their frequent use negatively: ‘I would also say it’s a bit more critical. I notice it with myself that I tend to do that and do it more often, but I whitewash it’ (participant 1.5, female, 19).

Tolerance

Some users reported a lack of effect when maintaining the same nicotine dose. For example, participant 2.4 (female, 26) noticed that she ‘relatively quickly had to dose quite high, because these low nicotine doses (…) have not achieved the effect that I had desired.’ She assumed that because e-cigarettes can be used continuously, she had developed tolerance: ‘It’s not limited to the rhythms of the individual cigarettes, as you [another participant] say, but somehow it goes on virtually all the time. I have the feeling that you can build up a tolerance relatively quickly.’

Perceived benefits

Many of the participants reported vaping in stressful situations for example ‘when I am annoyed with a customer or colleague’ (participant 5.3, male, 39) or on the way to an important exam. Even without acute stressors, participants noted that they would use their e-cigarettes to create a relaxed atmosphere, for example, participant 4.1 (male, 36) reported: ‘It just adds coziness when I sit on my sofa in the evening.’ Participant 2.4 (female, 26) vividly described: ‘So the effect that I wanted to achieve or that I had a need for, is when I have vaped three, four puffs, that I then notice how my system feels like it’s shutting down. So that is how I become very calm. Many muscles relax at once. I notice how I then sit upright, that I can sit in such a way that I, for example, just balance my head on my neck. So really finding a relaxed position. Or just in situations where I have the need for it. That’s more a situation where I'm sitting cramped at my desk.’

Withdrawal symptoms

In the discussion, users reported feeling symptoms of withdrawal when not being able to use their e-cigarette frequently. For example, participant 3.1 (female, 60) reported feeling ‘like on cold turkey’ when she tried to vape liquid without nicotine, and participant 2.4 (female, 26) compared it with feelings of hunger or thirst. Participant 5.1 (37, male) related ‘if I don’t balance my addiction by just getting my e-cigarette, my sense of well-being will lower accordingly.’ Other users shared the feeling of getting nervous when they forgot their e-cigarette. To avoid this situation, many users reported having a spare e-cigarette or battery with them at all times.

Craving

Craving for e-cigarettes was a feeling frequently discussed in the focus groups, often in relation to feeling addicted: ‘Sure, the term addiction is always a bit negative, but let’s be honest: what else could it be? I would not say I get nervous, but I already have an uneasy feeling just after I get up in the morning (…). Yes, that is definitely addiction’ (participant 4.1, male, 36). Many users reported rituals involving e-cigarette use that they were not able to quit, such as vaping breaks at work or combining vaping and the first cup of coffee in the morning. For example, participant 5.3 (male, 39) told the group ‘for me it has actually become a bit of a ritual: I get into the car and as soon as I’m driving I have the vape in my hand.’

Use despite harm

Three themes fall under this domain; Use despite health and social consequences and use despite danger. Few users reported e-cigarette use despite subjective health consequences: ‘I do not think my lungs are happy about it [vaping]’ (participant 3.1, female, 60). Another person reported an irritant cough (participant 4.1, male, 36). When discussing health effects, users also reported not being sure how harmful e-cigarettes are ‘You don’t really know what is in the liquids, how healthy they really are. There are always chemical additives’ (participant 3.1, female, 60). Different chemicals such as glycerin were discussed in this context, as was nicotine: ‘So the nicotine that’s in it [the vape] that’s the unhealthy bit. That is indisputable. Nicotine is unhealthy, and you vape it anyway’ (participant 2.5, male, 64).

Use despite social consequences was also reported by users, for example, vaping even though being perceived as ‘uncool’ by peers. Some users related that among their smoking friends or colleagues, vapers are seen as weird and are sometimes made fun of: ‘That are the people sucking on an external hard drive’ (participant 2.1, male, 29). Participants younger than 20 (n = 3) all had parents who wanted them to stop vaping. One participant (1.5, female, 19) related that her mother ‘thought it was better that I tried to change over, so to speak. But she still doesn’t think it’s good that I have a vape now.’ Since e-cigarettes are less obtrusive than cigarettes, some users also would vape in situations where it is forbidden: ‘Well, the nice thing about vaping, even at work, is that if you’re in an empty room, you can still vape and no one will notice. You can’t do that with a cigarette’ (participant 3.1, female, 60). Participants reported vaping in places where it is not allowed such as the hospital, in the bus, or in the office.

None of the members of the focus group reported use despite danger.

Impaired control

None of the participants mentioned that they had limited control over their e-cigarette use.

Automaticity

The automatic reach for their e-cigarettes was mentioned by many participants in the discussion, with some highlighting the unconscious aspect of their use: ‘For example, when I go for a walk, it [vaping] just happens unconsciously’ (participant 2.4, female, 26). Participant 1.3 (male, 19) related: ‘I think it’s also a bit subconscious. Sometimes you don’t have the urge to do it, but while walking you just get it out. You don’t have the urge to do it, but it’s just like that.’ Automaticity was explained by the participants with the ability to use e-cigarettes for a nearly unlimited amount of time: ‘Because you don’t have to light it up anymore. I can also just take a puff and stop. Tobacco cigarettes are usually smoked until the end. And that’s why you don’t notice how much you vape.’ (participant 3.1, female, 60). Moreover, users discussed that e-cigarettes are less obtrusive than cigarettes and thus used more automatically: ‘You use them much more carelessly. I was recently somewhere in a store and simply took it [e-cigarette] out and then used it in the store. And I wasn’t even aware that that wasn’t possible. It’s like a routine simply that you can use it and no one really bothers. There is no [cigarette] ash or something else, it’s simply different.’ (participant 1.6, female, 18).

Preferred over competing rewards

No user reported this.

Sensory dependence

Sensory aspects and enjoyment of e-cigarette use were frequently highlighted by the users. Many reported having a favorite liquid, pairing certain liquids with their morning coffee or lunch, or using sweet liquids when craving sugar. For example, participant 5.3 (male, 39) told the group ‘On the couch in the evening I will have something special. To a certain extent simply because it’s fun to try it out. And yes, I'd say it’s also a reward function, when you vape some chocolate pudding in the evening or whatever - there are so many things. It’s also fun - no question about that - trying it out.’ Other users also felt that vaping was fun: ‘The thing about liquid flavors, that’s fun. With [tobacco] cigarettes, I never had the feeling that it was fun’ (participant 1.5, female, 19). For many users, not just the taste but also the smell was perceived as pleasant, especially in contrast to tobacco. This also led to e-cigarette use indoors: ‘Yes, I also do this [vaping] a lot alongside [other activities]. I've just done a lot of it during my final exams, so while studying in my room and with [tobacco] cigarettes, I didn’t smoke in my room, also because of the smell. And that’s just kind of fun, so it’s just an activity on the side like chewing gum at some point. (…) And then I have the feeling that I sometimes forget that I still have nicotine in my liquid.’ (participant 1.5, female, 19).

Results of the inductive analysis

Our initial deductive analysis was based on the 10 domains of e-cigarette addiction as defined by Bold et al. (2018). Since our goal was to better understand the addictive potential of e-cigarettes, we then inductively coded specific properties of e-cigarettes and how they relate to subjective experiences of addiction. The results can be seen in Figure 1. We identified three properties specific to e-cigarettes that facilitate addiction: First, the virtually unlimited usability led to a high quantity and frequency of use, experiences of tolerance as well as automatic use. Second, enjoying liquid flavors led to craving and sensory dependence. Moreover, different liquids were used to create a relaxed atmosphere or as a reward. Third, the unobtrusive usability allowed users to vape in various situations, leading to automaticity and a higher quantity and frequency of use.

Figure 1. Model of the addictive potential of e-cigarettes (MAPE). Two of the domains (impaired control, preferred over competing rewards) identified by Bold et al. were not found in this study and therefore are not depicted here.

Discussion

This study analyzed focus group discussions to elucidate the addictive potential of e-cigarettes. We conducted five focus groups with a total of 14 e-cigarette users, who all solely used e-cigarettes with nicotine-containing liquid. First, focus group discussions were deductively analyzed based on 10 previously defined domains of e-cigarette addiction (Bold et al. 2018). All domains, except for ‘preferred over competing rewards’ and ‘impaired control’ were reported by focus group participants. We then used an inductive thematic analysis to identify the addictive potential of e-cigarettes and how it relates to experiences of addiction. The results of the analysis are summarized in the proposed Model of the Addictive Potential of E-cigarettes (MAPE; Figure 1). According to the MAPE model, three properties are central to the addictive potential of e-cigarettes: unlimited usability, pleasant taste, and unobtrusiveness. These properties facilitate experiences of addiction such as automaticity or withdrawal symptoms.

Our proposed model to explain the addictive potential of e-cigarettes is the first of its kind, yet it aligns with findings from previous research (e.g. Simpson et al. 2021). As in our study, previous research identified liquid flavor as central to the addictive potential of e-cigarettes. An experimental study with e-cigarette users demonstrated that liquid flavor increases the rewarding experiences of e-cigarettes (Audrain-McGovern et al. 2016) and heightens withdrawal experiences (Douglas et al. 2022) compared to unflavored liquids. With new flavors constantly entering the e-cigarette market (Zhu et al. 2014), it is unsurprising that the taste of e-cigarettes is perceived as enjoyable by most users (Chen et al. 2019). Likewise, in our focus group discussions, e-cigarette flavors were an important part of the user experience with users reporting having a favorite liquid and choosing liquids for specific occasions or rituals.

Another important factor for e-cigarette dependence that emerged from our research was the virtually unlimited usability. In contrast to tobacco cigarettes, e-cigarettes do not have to be lit up and can be used for a longer period of time. Most models on the market last about a day before they have to be recharged. Thus, they can be used without a break, a feature which participants in this study identified as a reason for automatic and frequent use. Participants also found it hard to assess how much they vape, reflecting other qualitative research showing the difficulty in assessing the quantity of personal e-cigarette use (Kim et al. 2016; Sanchez et al. 2021; Simpson et al. 2021). Indeed, in recent qualitative studies, lack of awareness of one’s own e-cigarette use appears to be a prominent theme, which participants attribute primarily to the convenience of vaping (Sanchez et al. 2021; Simpson et al. 2021). The constant accessibility of the device and the possibility of instant gratification – which participants referred to as ‘adult pacifiers’ – represent characteristic features of e-cigarette use (Simpson et al. 2021). Limiting e-cigarette use, for example by including a signal or automatic stop after a certain amount of nicotine has been consumed could help users to control their use. However, it should be noted that the majority of e-cigarette users in our study used low nicotine strength, which could lead to compensatory vaping, possibly explaining their frequent use (Dawkins et al. 2018).

As was related by users in this study, the unobtrusiveness of e-cigarettes makes it easier to vape at home or in secret. Further qualitative research substantiates these findings, showing that the discreetness of e-cigarette use encourages individuals to vape in various places and at any time without restrictions (Sanchez et al. 2021; Simpson et al. 2021). According to a survey among 462 US e-cigarette users (Yingst et al. 2019), two-thirds regularly vape in places where it is prohibited, a behavior called ‘stealthing’ among vapers. Our study showed that this specific property led to more frequent use, since users could secretly vape in places where it would be socially unacceptable or forbidden and vape where they had previously not smoked because of the unpleasant smell of tobacco cigarettes (e.g. at home, in a car). This finding is consistent with the qualitative study by Simpson and colleagues (2021), in which participants reported using their e-cigarette more frequently than they had previously used tobacco cigarettes, which they attributed to the lack of vaping restrictions in public.

Interestingly, no participant in our study reported enjoying making vapor clouds. While the ability to generate vapor clouds has been identified as an important property of e-cigarettes in previous research (Tokle and Pedersen 2019), it seems that this feature might not play an important part in facilitating addictive symptoms. However, as our sample was quite small, this hypothesis should be investigated more in depth in other samples.

To our knowledge, this study was the first to investigate the validity of the 10 domains of e-cigarette addiction proposed by Bold et al. (2018). While we could identify subjective experiences of eight domains, participants did not report impaired control or forgoing other rewards or activities to use their e-cigarette. This could be due to the fact that participants were not specifically asked about this topic in the interview, potentially leading to a bias in the obtained results. However, our previous netnographic study of subjective addiction experiences also did not find that e-cigarette users give up other activities for their e-cigarette use (Szafran et al. 2023). One explanation might therefore lie in the unobtrusiveness of e-cigarettes, meaning that few spaces are off-limits for e-cigarette use. Our results indicate that ‘preference over competing rewards’ is probably not an adequate domain to measure e-cigarette addiction.

Interestingly, in terms of ‘use despite social consequences’, our respondents indicated that they use their e-cigarette even though it is perceived as ‘uncool’. This is in contrast to other research findings, where participants considered e-cigarettes as ‘cool’ (Kong et al. 2015) and reported enjoying social aspects of e-cigarette use, such as learning e-cigarette tricks and sharing information via social media and with their peers (Simpson et al. 2021). However, these studies have focused on adolescents and young adults in the U.S., and the perception of e-cigarettes likely varies across countries and age groups. Moreover, it is worth noting that the reported social consequences (negative perceptions by others) are relatively minor compared to typical criteria of substance use disorder. Substance use resulting in a failure to fulfill major role obligations at work, school, or home (as defined by DSM-5) is seldomly reported by e-cigarette users (Szafran et al. 2023). This could also be due to the unobtrusiveness of vaping and the relatively high level of functioning in e-cigarette dependence compared with other substance use disorders (e.g. alcohol use disorder).

This study is only one piece of the puzzle toward understanding the addictive potential of e-cigarettes. The interdisciplinary EVAPE project aims to provide a more complete picture of the addictive potential of e-cigarettes with neurobiological and longitudinal epidemiological data (Vollstädt-Klein et al. 2021).

Limitations

This study investigated subjective experiences of e-cigarette addiction in a group of 14 German e-cigarette users diverse in age and gender. Some limitations to the research need to be considered. First, e-cigarette users participating in this study were self-selected. Recruiting e-cigarette users was difficult, despite offering a monetary incentive. While we used various recruitment strategies to obtain a diverse sample, we might have overlooked important voices that could not be reached. Second, self-reports of e-cigarette use, especially dual-use, have been shown to be inaccurate in other studies (Goniewicz and Smith 2019). Unreported dual-use might influence experiences of addiction and thus impact our analysis. In addition, the addiction domains by Bold et al. (2018) were not explicitly addressed in the interviews in order to not ask suggestive questions. However, this also has the disadvantage that some domains could not be explicitly discussed because they were not mentioned by the participants. Finally, like all qualitative research, the results presented here are not generalizable; however, we provide a model that can be tested with quantitative methodology in the future.

Conclusion

Our analysis of focus group discussions with e-cigarette users yielded two central results. First, subjective experiences of e-cigarette addiction discussed by users accorded with most domains of e-cigarette addiction as defined by Bold et al. (2018). Second, we identified three unique central properties of the addictive potential of e-cigarettes: Unlimited usability, pleasant taste, and unobtrusiveness. These results can inform structural prevention measures, cessation programs as well as the refinement of instruments to measure e-cigarette addiction.

Open Scholarship

This article has earned the Center for Open Science badge for Preregistered. The materials are openly accessible at 10.1186/s40359-021-00682-8.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

The data that support the findings of this study are available in German on request from the corresponding author [MA]. The data are not publicly available since they contain information that could compromise the privacy of research participants.

Additional information

Funding

The German Research Association (Deutsche Forschungsgemeinschaft) provided funding as part of the Evaluation of the Addictive Potential of e-Cigarettes project [grant 437718741] and provided financial support for the article processing fee within the funding program ‘Open Access Publikationskosten.’ UM and VL are supported by the Marga and Walter Boll Foundation.

Appendix A.

Guide for focus group discussions (translated from german)

Introduction

Thank you very much for agreeing to participate in our focus group discussion. As you know, this focus group is part of the EVAPE study. In this study, we want to find out more about the experience and perception of e-cigarette users. I am [name of interviewer] and this is my colleague [name of student assistant]. We are both working on the EVAPE project. In today’s discussion, we would like to talk to you about your personal experiences regarding e-cigarette use. We invited you because as an e-cigarette user, you know the most about the topic and can give first-hand accounts. Everything you tell us is an important contribution to our research. There are no wrong answers. Therefore, we would like to ask you to speak openly and freely. We also encourage you to share your opinion if it differs from others. There is only one rule today, and that is: please do not interrupt other participants. You know that our meeting today will be recorded on audio and transcribed afterwards. In the process, all personal data (e.g. names, locations) are pseudonymized, meaning it is not possible to draw conclusions about you or any other third parties you may be talking about today. Your audio recording will not be played to anyone. We would like to point out that you can leave the discussion at any time. The discussion will last approximately one hour from now on. Do you have any questions about the process? If not, we will start now.

Introduction

At the beginning, we would like to start with a short round of introductions. Please say your name and how you started using e-cigarettes in one sentence.

Advantages vs. disadvantages

Thank you for describing your first experience with e-cigarettes. What are the advantages and disadvantages of vaping for you personally? For this, you can take pieces of paper and write down advantages and disadvantages. When you are done, stick the pieces of paper on the whiteboard/flipchart. (Alternative for the online session: Jamboard)

Discussion of results:

• I see XY here a lot. Would you say this is an important aspect?

• Only one person wrote X. Do others feel the same way?

• Can you say more about X?

Tolerance

The special thing about the e-cigarette is that you can dose the nicotine levels as you like and thus adapt it to your own needs. We are interested in how do you handle this?

Thinking back to when you first started using or switched to e-cigarettes, to what extent has your nicotine dosage changed over time since you started vaping?

• If changed, what were the reasons for increasing/decreasing the dosage?

• In what ways did it become apparent that you should change the dose?

We are interested in how difficult it is to reduce nicotine levels. What has been your experience with reducing levels?

• How difficult did you find it to reduce the level?

• What changes occurred when you reduced the level?

• If you have not had any experience with reducing levels: How difficult or easy do you think it would be for you to reduce nicotine levels?

Craving

We are also interested if you feel a craving to use e-cigarette. What about situations when you cannot/are not allowed to use e-cigarette, e.g. at work or right now. How do you feel about it?

• In what situations does a craving for the e-cigarette (still) occur?

• How do you recognize the craving? What thoughts occur when you do?

• How often does it occur?

• Do you find it distressing and if so, why?

Now we will discuss situations in which you can vape freely.

• What is your vapor behavior like then? How often do you use your e-cigarette there?

• Former smokers among you may remember how strong the craving for a cigarette was in certain situations, e.g. after eating, in the morning after getting up or when other people smoked around you. How does this compare to e-cigarette use?

Last question

This study is about the addictive potential of e-cigarettes. How do you feel about the term addiction in relation to e-cigarettes?