Digital technologies, including smartphones, social media, and online games, have become integral to adolescents' daily lives. But how do they truly impact their well-being? For years, studies have raised concerns about potential harms, yet most relied on methods that could not establish cause and effect. Over six years, the Interdisciplinary Research Team on Internet and Society (IRTIS) conducted 15 rigorous studies in the Czech Republic using advanced methods (longitudinal studies, experiments, and real-time assessments) to uncover how digital technologies impact adolescents’ psychological, social, and physical well-being. Our findings challenge simplistic narratives. First, the impact of technology is not uniform - some adolescents experience increased stress from smartphone use, while others do not. For instance, searching for health information online heightened anxiety in those already prone to it, but not in others. Second, what matters most is how technology is used, not just general screen time. While social media use had small negative effects on psychological well-being, gaming and entertainment apps did not show the same pattern. Third, different aspects of well-being are affected in different ways—while digital technology influenced adolescents’ physical self-worth, it had no measurable impact on their social skills. To conclude, digital technology does not affect all adolescents in the same way, whether positively or negatively. Instead of one-size-fits-all conclusions, our research highlights the need for a more nuanced approach—one that considers individual differences, specific online activities, and the broader context of adolescents’ lives. Rather than debating whether digital technologies are ‘good’ or ‘bad,’ and providing general bans, policies and interventions should focus on supporting adolescents in developing healthy, constructive ways to engage with them.

This research report explores the relationship between AI and health, focusing on the perspective and experiences of Czech adults. It focuses both on the general use of AI and on the willingness to use AI to search for health information (i.e., disease diagnosis, treatment options, causes of the symptoms, proper exercise, weight maintenance, healthy eating). It also maps the level of trust in the health recommendations that AI can provide.

Adolescents commonly use smartphone social media apps, which can affect their perceived social support (PSS). However, study results on social media’s effect on PSS differ, because they employ a self-reported time in social media use and concentrate only on between-person differences. They often neglect the social-anxiety level, which might be important. Our study investigated whether the within-person day-to-day changes in the time spent in two types of social media apps (communication and social networking) influence the daily PSS and vice versa, and whether social anxiety moderates these relationships. Using a mobile application that was installed on adolescents’ smartphones (N = 194), we collected the daily objective time spent in apps and the self-reported PSS for 14 days. Social anxiety was assessed with a baseline survey. The models showed that day-to-day changes in communication and social networking app use did not influence the PSS the next day and vice versa. Social anxiety did not moderate these relationships. We further elaborate on the variability related to the within-person effects.

In this report, we show how much time the participants of our study spent using their phones and each app category every day, and how this usage varied by gender, age, day of the week, and over the course of the year. We also present data on phone usage during the day. Finally, we discuss how many times a day adolescents used their phones and how the frequency of use varied by type of use.