Below, the most important themes and subthemes from the focus group interviews are presented. Themes are presented as a title; subthemes are indicated with a bold font. The major themes involving identified factors of sleep are defined in Table
2 in the methods section. Due to practical considerations the number of focus group interviews was decided upon before the start of the study. No new information was obtained after analyzing the 5th focus group interview, meaning data saturation was reached. Nevertheless, all nine interviews were analyzed.
Knowledge about recommended amount of sleep, sleep hygiene and health benefits of sleep
Adolescents had different opinions on what the recommended amount of sleep is, ranging from seven to twelve hours.
“I think we should sleep eight or nine hours.” (9th grade technical education, boy).
“Seven to eight hours.” (9th grade technical education, boy).
“Eleven.” (9th grade vocational education, girl).
Most adolescents had a correct representation of what good sleep hygiene consists of. Nonetheless, several adolescents still experienced some misperceptions regarding good sleep hygiene, such as considering the performance of sports right before bedtime as a good practice. Moreover, additional aspects of sleep hygiene such as adjusted room temperature were not mentioned.
“Don’t watch TV half an hour before you go to sleep.” (9th grade technical education, boy).
“Don’t use your cell phone while in bed, or something like that.” (8th grade general education, boy).
“Do not drink Coca-Cola or eat and drink something with a lot of sugar.” (10th grade general education, boy).
The most important misperception on sleep hygiene was the idea of ‘catching up’ sleep during the weekend by sleeping in. A lot of adolescents indicated that they slept in during weekends, as a response to the fact that they do not have to wake up for school.
“I always try to catch up on sleep during the weekend and then I always think it’s alright again.” (10th grade vocational education, girl).
“During weekends you are allowed to sleep as long as you want, during weekdays you have to get up in the morning for school.” (9th grade vocational education, girl).
Finally, adolescents mostly talked about the short-term benefits as possible advantages of a sufficient amount of sleep (such as being energized, concentrated, better moods and memorizing), and not or to a lesser extent about long-term effects of poor sleep.
“You can concentrate well, you don’t get sick so quickly.” (10th grade technical education, girl).
“It is important to sleep well, to feel good about yourself.” (9the grade technical education, girl).
“You are fit to pay attention the next day.” (9th grade general education, girl).
“When you do not sleep enough, you are moody, which is annoying for other people.” (10th grade general education, girl).
Facilitators
Some adolescents indicated their smartphone as a facilitator of falling sleep. Others listened to music (on their smartphone) or read a book to fall asleep more easily.
“That is why people are on their smartphone for a longer time, that’s true for me anyway, I’m using my phone to get to sleep and then it’s pretty late before I sleep.“ (9th grade general education, boy).
When asked what they felt would help them to sleep better, several suggestions were given, such as leaving the smartphone downstairs, being physically active during the day, reading a book or setting an alarm which signals bedtime.
“I think if I would leave my cell phone downstairs I would get to sleep better and faster.” (10th grade general education, boy).
Barriers
Several barriers of healthy sleep were mentioned by adolescents, ranging from behavioral factors (such as screen time) to environmental factors (such as the starting time of schools) or emotional factors (such as ruminating).
All participants agreed that smartphones are the most important barrier to reaching a sufficient amount of sleep. Adolescents indicated that especially chatting (individual or in group conversations) stops them from going to sleep because they do not want to miss the further course of the conversation. They also mentioned losing track of time whilst texting or playing games on their smartphone. Finally, adolescents indicated that they would prioritize chatting over sleeping.
“The mobile phone is the main reason why I sleep late. I am on Facebook and all.” (10th grade technical education, boy).
“Yes, in the evening there are just so many people who text me and more is happening.” (10th grade technical education, girl).
“It would be better if I slept after 10 o’clock but I never succeed, so then I play something on my mobile, but then it quickly turns 11 o’clock or 12 o’clock.” (10th grade general education, boy).
“If you have to go to sleep earlier than your friends for example, then you are already sleeping while everyone is still sending messages or talking.” (8th grade technical education, girl).
Like conversations on smartphones, the fear of missing programs on television also influences adolescent’s bedtime. Adolescents said they find it annoying to miss TV programs, as they cannot join their peers who discuss the program at school the next day.
“Yes, and if you record a program, there are many friends who have already watched it, you cannot join the conversation and then it is no longer useful to watch it afterwards.” (10th vocational education, boy).
Also new technologies such as Netflix were mentioned as alternatives to television and as barriers.
“Yes, I watch Netflix, so I often lose track of time.” (10th vocational education, boy).
Adolescents also reported leisure activities as barriers to reach a sufficient amount of sleep, and reported that they were prioritized over healthy sleep.
“If you have to be somewhere until a quarter past eight or nine o’clock and then you still have to go home and wash yourself, it will take a long time until you are finished.” (9th grade general education, girl).
“Like your weekly sport activity or something, you hang out a bit longer or drink something in the canteen.” (9th grade general education, girl).
“Yes, if I had to go to sleep at nine, I would have to stop gymnastics and I don’t want to.” (9th grade technical education, boy).
Not all adolescents but a vast majority of young people indicated that schoolwork had an impact on their sleep. Due to the high amount of schoolwork, adolescents indicated that they go to bed later and that they experience more stress, resulting in increased difficulty falling asleep.
“Schoolwork, that’s why I go to bed later.” (10th grade general education, boy).
“Yes, especially stress actually. The pressure to get really good points at school that completely determines your life, you’re thinking about it a lot.” (10th grade general education, boy).
“I go to sleep too late because we have too much homework.” (8th grade general education, girl).
In line with this, worrying or ruminating was also mentioned by some participants as a barrier to falling asleep at an appropriate time.
“Yes, sometimes worrying.” (…) “What happened during the day or something like that” (10th grade vocational education, girl).
In addition, the starting time of school was also experienced, by some adolescents, as a barrier to reaching a sufficient amount of sleep.
“I sleep too little because I have to get up for school.” (10th grade general education, boy).
“I know, just let school hours start a little later… Then we would have more time to sleep, we would wake up faster and now we must be here at eight o’clock… That’s way too early” (8th grade general education, boy).
Finally, noise created by siblings in the room, parents, neighbors or environmental noise was mentioned as a barrier for high quality sleep.
“If they are playing music that is super loud, I have trouble sleeping.” (9th grade technical education, girl).
“Gosh yes, I always hear sounds. For example, in my room, sometimes the radiator ticks.” (8th grade technical education, girl).
Perceived behavioral control to change sleep
Most adolescents indicated that it would be hard to change their sleep. They felt that they would not be able to sleep if they would go to bed earlier, assuming that the sleep latency time would extend. Some adolescents also indicated that they would feel embarrassed telling peers that they want to sleep instead of chatting.
“If you tell people to go to bed an hour earlier, it would be almost impossible in the first few weeks because they are used to going to sleep much later… You would definitely lay awake.” (9th grade technical education, boy).
“If you suddenly get into bed at nine o’clock you can’t sleep either.” (10th grade general, boy) “No, because you are so used to going to sleep at ten and getting up at seven and if that suddenly changes, that will not work.” (10th grade general education, boy).
“I really have no discipline to go to bed earlier” (8th grade general education, boy).
“If you’re having a conversation and then have to say, I’ve got to sleep and it’s nine o’clock or something, that’s a little embarrassing to me.” (8th grade technical education, girl).
Perceived norm
Although adolescents found it difficult to estimate each other’s sleep, they assumed that their peers did not sleep enough and rated the sleep of their peers as poor. In addition, they assumed that their peers had a long sleep latency time.
“I think the others sleep eight or nine hours.” (8the grade general education, boy).
“Less for sure, seven hours or so.” (9th grade vocational education, girl).
“Eight hours is too much, if you ask around in our class. Most of them sleep six or seven hours or so.” (10th grade technical education, girl).
“I think we all sleep too little.” (8th grade general education, girl).
“I think it’s hard for peers to fall asleep.” (9th grade general education, girl).
According to the participants smartphones were the main reason for the poor perceived sleep of their peers.
“Researcher: and how well do you think they sleep?” “All: not good” “Researcher: Why do you think so?” “Because of smartphones and electrical devices.” (10th grade vocational education, girl).
Family support: family rules
Several adolescents mentioned family rules regarding bedtime as a factor influencing their sleep. For some adolescents, a fixed bedtime was also accompanied by handing over the smartphone to the parent(s) when going to bed. Although some adolescents acknowledged these rules as having a positive influence on their sleep, others indicated that these sometimes provoked feelings of irritation or frustration which then had a negative effect on their ability to fall asleep. Adolescents thought it would be easier if the rules were mutually discussed in advance.
“My parents tell me to leave my smartphone downstairs.” “Researcher: And does that help?” “Yes, I think so because otherwise I would continue to send text messages and now I have to go to sleep at some point, otherwise I would keep texting and fall asleep much later.” (10th grade general education, girl).
“My mom used to take my cell phone and I became so annoyed about it that I couldn’t sleep either. Suppose you want to send something, and she takes it away, then it’s just like you are ignoring someone, which is an annoying feeling because you were not able to finish the conversation.” (9th grade technical education, boy).
Involvement in the development (and implementation) of a healthy sleep intervention
Adolescents had a positive attitude towards being involved in the development and implementation of a healthy sleep intervention. This was considered interesting and important by the adolescents, and they mentioned that it would help them improve their own sleep. Furthermore, they indicated that it would be essential for them to share their opinion, since they are most able to advocate what is interesting and important for adolescents.
“When it comes to youth, it is important that we say what we think.” (10th grade general education, boy).
“I would help, because it will make yourself better and others will also benefit.” (9th grade general education, girl).
However, they had a low sense of self-efficacy to complete this task autonomously. Consequently, they felt that it wasn’t necessary for them to play the most important role in the entire process. In addition, adolescents felt unable to do this independently due to a lack of experience and expertise, and being too young to take on such responsibility. They indicated that it was important that an older person with more experience and knowledge (such as people connected to the university, teachers, school management or their parents) would guide them through the process.
“I would not know what needs to be done.” (…) “If it is a lot of work, then I don’t want to do it, because I am someone who wants to do everything well.” (9th grade general education, girl).
“Yes… we need guidance.” (10th grade general education, girl).
Sleep intervention ideas
When asked if they could already generate some ideas for this hypothetical intervention, participants came up with several ideas: a quiz on sleep, a competition between class groups to sleep the most, rewards when performing some tasks, setting a goal, developing an application to monitor sleep or sleeping as much as possible with the intent of raising money for a charity.
“An app or something, then you can always fill it in and receive feedback.” (10th grade general education, girl).
The students unanimously agreed that school would be the ideal setting for a sleep intervention, because of the already existing bond between the students and the fact that young people are easily accessible at school.
“I also think it would be good to do it at school, you know everyone, you see each other every day, I think that’s better than with people you don’t know.” (9th grade general, girl) “Yes, you can help each other. (9th grade general education, girl)
“Yes, I think so, because it is an assembly point of young people that could use some advice on healthy sleep.” (10th grade general education, boy).