Table 7 Definitions of and examples of all domain summaries and subdomains.

Therapeutic relationship

This main theme encompasses the experienced or non-experienced qualities of the relationship with the e-coach (the person conducting the guidance in the SOPHIE programme).

Burdensome

This subtheme contains experiences of stress and burden. By looking at completed exercises and commenting on them or giving feedback, the e-coach made adolescents feel guilty or pressurised, they were afraid of disappointing the e-coach if they do nothing/something wrong. Furthermore, adolescents explain that they did not know how to interact (are they expected to write back/not?).

Emma (17. 02): “I found it a bit uncomfortable, (…) I hadn’t worked on a module for a week because I was really stressed, I still had school and so that week, I didn’t think about it at all, it was a bit stupid, and then I got a message from the e-coach saying (…) I haven’t completed one, I totally had the feeling of pressure, oh god I’ve forgotten something, I hope they still like me.”

Nora (16.02): “Mmh, well, I didn’t really answer because it always made me very nervous to know that someone was looking at what I was working on.”

Supportive

In this subtheme, e-coaches are described as warm, supportive and understanding. Adolescents felt seen and recognised that they are being addressed personally (emotional component). E-coaches give feedback, answer questions, explain how to proceed and are perceived as helpful (structuring component). This structuring goes beyond reminders.

Emily (16.05): “I thought it was good because you could write the e-coach all the time. They replied pretty quickly and gave me tips. I thought that was good. So, I also thought it was good that everyone was supported during the time and that they didn’t just say ‘yes, go through the 6 modules and if you have any questions well that’s too bad, but we can’t help you’, but that you were supported, that you could always turn to the e-coach, yeah.”

Lea (17.07): “Ehm, so I found that helpful. (Alessja: Mhm) And I found it nice that a person tells you that you can continue [with the next module] and not just an automatic message. I found that a more personal thing.”

Unpersonal

This subtheme captures the experience of having “no” relationship. Adolescents perceived the interaction as impersonal and wonder whether it is a Chatbot/artificial intelligence. They perceive no contact person (as compared to face to face, for example).

Emma (17.02): “Well, I didn’t really see a relationship if I’m honest, I didn’t know exactly, I didn’t want to answer because I didn’t want to cause anyone any stress, so yes, I thought it was a bit, they always wrote me the same thing and then I thought it was a bit like a bot, like a not a person or something.”

Factors contributing to or preventing engagement with the intervention

This main theme contains factors that contribute to or prevent adolescents from engaging with the intervention. In contrast to adherence that assesses engagement with a predefined (amount of content), this theme encompasses subjective factors that support adolescents’ engagement with the intervention

Problem awareness and motivation to change (initial Engagement)

In this subtheme, adolescents recognize their problems, symptoms or challenges and would like to learn how to handle these situations differently with support of the intervention.

Anja (16.06): “Ehm I just realised that I have social anxiety and that it would be cool to try to do something about it. And then I realised that there was this study and the things on the videos applied to me and I thought it was a good opportunity to start something.”

Emma (17.02): “Ehm, so mainly my fears, firstly that I can’t participate verbally and then that I might be afraid to show myself to others, that I’m afraid of what others might think about me and to find out what’s going on in my body and why I’m afraid, what’s causing it.”

Interest in the content/topic supports engagement

This subtheme entails adolescents interested in the programme, the topics or research as a reason to engage with the intervention (not necessarily linked to own situation).

Anja (16.06): “Ehm I just wanted to try it out and see if it helps me [and] I was interested - I don’t know.”

Sophie (15.05): “Ehm honestly, I was just curious about what was still to come. As for the ending, the way it ends, so to speak.”

Experienced self-efficacy leads to continuing engagement

This subtheme contains recollections of symptom improvements due to the SOPHIE programme. Adolescents experience themselves as self-effective with the support of the programme and motivated to experienced symptom change and indicate this as the reason to keep using it.

Nora (16.03): “Mmh, I usually worked on one [module] every week, so I usually had time to realise that the modules really help, and I always found it very interesting to learn about anxiety and that motivated me to keep going.”

Lea (17.07): “I would also say that I saw a small improvement, that also motivated me to keep going.”

Design, structure and reminders support engagement

This subtheme entails references to the module-based structure (one per week), the reminders by the e-coaches or parents support that supported adolescents’ engagement with the intervention

Emily (16.05): “[I liked] that you could actually click through the programme every week and you could write down things that you noticed or that happened every week and then you could see them again and then see whether you got better at them or whether they stayed the same.”

Lara (11.10): “Mostly my mum also told me that I still had to do it or sometimes I was told by my e-coach so I received a message and it said that I still forgot to do one module or something.”

Online delivery promotes autonomy and flexibility

In this subtheme, adolescents appreciate the anonymity and independence an online intervention holds for them. Some adolescents mention the fact that they do not have to meet a person or travel anywhere, others appreciate that the programme is at no cost, the freedom to decide for themselves which exercises they want to do, the time flexibility and the sustainability (the intervention can continue to be used after official completion).

Elin (15.03): “I went to a therapist, but it didn’t work properly because I didn’t feel comfortable with the person. And then I thought I’d try it myself first. And that it was still somewhat guided, I thought that was a very good option.”

Sara (16.11): “I found it very interesting that it’s an online programme and you don’t have to go somewhere and see a therapist or anything like that. And yeah, I thought it was good that different exercises were offered, and you didn’t always have to try them all.”

Other commitments and lack of time prevents engagement

In this subtheme, adolescents describe that they did not use or forgot to use the online programme due to exam stress, too little or no time, or other leisure activities such as holidays.

Anna (16.10): “I just, I think I had almost no time two weeks before the end because there was so much going on. At school and everything. And I don’t know, maybe I could have divided it up differently or something, I had the feeling that I should do something, but at the same time I didn’t find any time.”

Elin (15.03): “I’m a very forgetful person, which means I forget a lot. Even things that I actually know I still have to do.”

Adolescents reflect on their symptom and behaviour changes

In this main theme, adolescents reflect on possible subjective changes in their behaviour and symptoms.

Adolescent recount observable implementations in their daily life

In this subtheme, adolescent recount observable implementations in their daily life. They describe how they apply content (e.g. strategies, exposure exercises) in their everyday life; thereby, this theme is focused on implementation and not on understanding psychoeducational content.

Emma (17.02): “I was able to come up with my own phrases [words of encouragement] and I also got input on what I could use for phrases. I was able to recall [them] in my head the moment the panic raised. I thought that was really cool that I was sitting there in class and when the panic started, I sayed to myself ‘I’m enough and I can do it! And if not, there are other opportunities, no stress, it’s all good’.”

Mia (15.07): “Ehm. So, it certainly worked well for me to plan situations like that [exposure exercises] and then put them into practice. It also helped to know, okay, now I’m going to do this and setting a date also helped.”

Difficulties implementing changes in daily life

This subtheme contains accounts of adolescents of difficulties in implementing what they had learnt in the intervention into their everyday lives. Some adolescents also indicate that they would need additional support.

Anja (16.06): “The SOPHIE-programme definitely gave me some tips. I don’t know if I’m good at applying them because it’s sometimes difficult to think clearly in this situation. But I definitely got some tips.”

Linn (15.05): “I thought the fear pyramid was quite good, because you could show yourself what you are actually most afraid of and what is the worst thing for you. Ehm, but it was just a bit too difficult to put into practice, especially alone, I’d say. Because you are not able to ask questions.”

Subjective Symptom Change

This subtheme captures adolescents’ reflections on their subjective changes in symptoms

Personal problem(s) worsened or remain unchanged

This subtheme contains accounts of adolescents who report a lack of improvement or worsening of their symptoms or problems.

Louise (16.10): “Certainly on the one hand a few messages that I took away from the modules, e.g., thinking of a [safe and happy] place, but I think the whole programme, hadn’t helped me that much personally. I think it helped that I became clearer about what I could do better and that I now know what to do next and how to work on it. So I think it has helped me indirectly, maybe that I now have this motivation to change something and yes, even if the exercises didn’t work for me personally, I do think that it has triggered something in me that I want to improve.”

Personal problems ameliorated

In this subtheme, adolescents describe subjective improvement in symptoms or report on fewer problems.

Mia (15.07): “Ehm, I have two main problems, so to speak. One is giving presentations and standing in front of the class and speaking up and the other is talking to new people or generally starting conversations with strangers. And yeah, I think starting conversations and getting to know strangers has got better now and with the presentations, I haven’t had the chance to try it out yet because we haven’t had any presentations at school yet. But I think it will certainly get better.”

Adolescents think they need more time to experience significant change

In this subtheme, adolescents explain that they need more time before an improvement could take place.

Anja (16.06): “I have the feeling that it did get better. But I also have the feeling that I need more time so that I can apply the things from the programme even more (…) and have the confidence to do the things.”

Adolescents’ evaluation of SOPHIE intervention content

This main theme captures adolescents’ reflections on the SOPHIE intervention content.

Psychoeducational content was received as instructive, informative, understandable.

In this subtheme, adolescents report that videos, audios and texts were understandable, and that it was helpful to them to learn more about the topic. They report that content helped them understand their challenges and situation better.

Emily (16.05): “I thought it was good that there were videos in between so you could watch them again, then you understood what you had read. I thought it was very good that I could recognise myself a bit in the videos. That they were adolescents and not adults.”

Lea (17.07): “Ehm, so certainly a lot of people feel like me. And that if you keep at it, there are possibilities to change.”

Lucie (16.05): Ehm so in any case I got more information and examples from others of what [social anxiety] can look like and how you can observe it in yourself and that’s definitely made me a bit more confident. And I know better how to deal with it.”

Psychoeducational content was not relevant, too theoretical or not understandable for adolescent.

This subtheme contains descriptions of adolescents that the psychoeducational intervention content was not relevant to them and their situation. A few adolescents also report that they had difficulties to understand it.

Noah (16.04): “Mmh, I just had difficulties that I didn’t need it [the information] for myself because, as I said, I made progress relatively quickly at the beginning and developed further in that sense and yeah then you just didn’t do it [the programme] somehow.”

Interviewer to Neele: “If you didn’t understand something, could you ask your parents?”

Neele (11.00): “Exactly, my parents were usually able to help me, or they googled it. And if that didn’t work, then I went to my e-coach. But mostly my parents knew the solution.”

Exercises and practical applications were experienced as helpful and suitable

This subtheme captures adolescents’ descriptions of how they found the exercises and strategies useful, helpful and applicable for themselves.

Louise (16.10): “I thought that was good, so if I really made an effort and wrote in the logbook, then it stuck [in my mind]. And that’s why I think it’s good. I also thought it was good to look back and remember things. I think if nothing had happened after the exercise, I would have forgotten it even quicker than I have now.”

Interviewer: “So, the anxiety pyramid was the thing that helped you the most, why would you say it was so helpful?”

Neele (11.00): “Yes, I was able to make a timetable and write down very specifically that I would do it this way and that way. And that’s what it said on the timetable, then I must do it like this.”

Exercises and practical applications were experienced as not suitable for adolescent’s specific life situation.

In this subtheme, adolescents report that they cannot use the proposed exercises in their everyday life. In contrast to implementation difficulties, they don’t indicate to need additional support, but rather that the exercise does not fit their everyday life (e.g. the duration of the relaxation exercise is too long).

Mia (15.07): “So these exercises took quite a long time and you have to be able to apply them very briefly in these [social] situations, there wasn’t enough time for me to be able to do them. Ehm exactly, that was certainly the difficulty.”

Emma (17.02) on relaxation exercises “Yes, exactly. It was always about 10 minutes long and I really haven’t had that much time recently, especially with exams and school, so I’ve never really found time to lie down or sit down for 10 minutes and listen to it. I think I’m also a very impatient person and then I didn’t really manage to pick myself up and say sit down now, I pushed it to the back of my mind and only did it once or twice, which was a bit of a shame.”