Internet-based activities have greatly modified individuals' daily lives, and they have become even more important since the COVID-19 outbreak (Gjoneska et al., 2022). Indeed, people of all ages are taking advantage of widely available free-time-, work-, and education-related applications and platforms that help them connect with others and meet everyday requirements and responsibilities. Even if individuals may use online activities and services for health supporting and stress managing purposes (Zarco-Alpuente et al., 2021), scholars have also expressed concern about the influences of excessive internet engagement on youths' wellbeing and mental health (Kamolthip et al., 2022).

The behavioral effects derived from internet use depend largely on the nature of its use. Repeated and increased usage of online activities over a significant period may alter some vulnerable users to fit the profile of Problematic Internet Use (PIU), which has the characteristics of placing over-importance on online-based activities, causing individuals to lose control over their internet use with a further impairment to key areas of daily functioning (Fineberg et al., 2022; Kamolthip et al., 2022). The first studies in the field addressed this issue in terms of general multifaceted internet use (i.e., generalized PIU), but recently it has been acknowledged that PIU encompasses a cluster of different specific problematic internet-related subtypes (SPIU) including gaming, sex/pornography, gambling, shopping, social media, and chatting/messenger, which are associated with different sociodemographic and psychological variables such as age, gender, and personality traits (Fineberg et al., 2022; Kamolthip et al., 2022).

Internet-based activities are highly popular at any age, but youth and adolescents, are particularly attached to these mediums compared with older age groups, making them one of the main groups at risk of internet-related harms (Karacic and Oreskovic, 2017; Nesi et al., 2020). However, as PIU is related to different problematic online behaviors and age groups, this indicates that it may influence users throughout their whole lifespan (Zajac et al., 2017).

There is plenty of research on the effects PIU can have (Fineberg et al., 2022). Previous research on PIU has identified factors such as neurocognitive deficits (Ioannidis et al., 2022), theoretical models (Brand et al., 2022), clinical service methods (Roberts et al., 2022), genetic basis (Werling and Grünblatt, 2022), and current prevention strategies (Shi et al., 2022). The current Research Topic represents a collection of papers investigating the relationship between general or specific types of PIU (e.g., gaming, and social networking site use) and school performance and success, as well as further studies identifying the potential mechanisms connecting these factors.

Previous studies have shown that relative deprivation has an important and positive influence on gaming problems. One study by Yang et al. investigated potential mediating and moderating mechanisms to clarify how and under what conditions relative deprivation was positively related to gaming problems in disadvantaged children (N = 952). A deviant peer affiliation may have an important mediation role in the development of gaming problems. Furthermore, the association between relative deprivation and gaming problems was stronger for disadvantaged children with a higher degree of beliefs about adversity.

A study by Chen and Liu was targeted on junior high school students (N = 614) in China, exploring the mediation (i.e., internet entertainment usage preference) and moderation (i.e., future orientation) mechanisms of how family socioeconomic status predicted academic achievement. In this study, the moderated mediation model is based on the perspective of cultural reproduction and resilience theory. The authors conclude that improving the developmental level of adolescents' future orientation can form internet entertainment usage preferences and enhance the positive influence of the family's socioeconomic status on the academic achievements of adolescents.

Teachers' perceptions are currently underrepresented in research that addresses online challenges and harms. Throuvala et al. utilized qualitative interviews with teachers exploring perceptions of adolescent online engagement and recommendations of how schools could prevent the experience of online harms during adolescence. Their findings highlighted recommendations for online harm prevention in schools. Skills development and training in the digital environment were highlighted as important factors in the media education of parents and teachers.

Adolescents' in-game purchases (e.g., microtransactions and loot boxes), and purchasing styles (non-purchase, planned purchase, or unplanned purchase) were also explored in the sample of Japanese high school students (N = 335) to get insights into maladaptive behavior from the perspective of psychosocial adjustment and mental distress (Shinkawa et al.). Based on the findings it was concluded that the styles of in-game purchases may partially illustrate the varieties in psychosocial adjustment among adolescents. More precisely, gamers with unplanned in-game purchases reported more behavioral and peer problems compared to planned purchase gamers, and more overall difficulties compared to non-purchasers. However, it was alternatively argued that individuals with mental health problems may play digital games with in-game purchases as a coping mechanism to relieve their depressive mood.

The link between Child abuse experience and problematic internet use was also examined in the sample of Chinese university students (N = 918). Qin et al. investigated the mediating roles of security and maladaptive cognitions in the relationship between child abuse and problematic internet use. They found that child abuse could positively predict problematic internet use through the mediating role of security, and cognitions. These studies provided implications for the prevention and treatment of problematic internet use to influence students' school achievement.

As these above-mentioned research examples showed, the relationship between PIU and school performance in adolescents and young adults is a multidimensional issue. Gül et al. focused on identifying possible underlying mediators between those variables as well as the central drawbacks of the previous studies, and highlighted future directions in the field. Consequently, there are still questions that remain to be addressed, and specific themes warranting further research in this context.

Taken together, this Research Topic covers several aspects of problematic internet-based behaviors and school performance. These articles will provide researchers in the field's insights into the link between the use of online activities and school achievement. The results of the presented research show that these connections are complex and often assume the interaction of several psychological, social, and cultural factors. In addition, the research undertaken is fragmentary and is carried out in various age groups, which suggests the need for further, more structured research in this area. Identifying and systematizing the factors related to internet activity and those related to low levels of school achievement would be of great importance from the point of view of developing preventive measures aimed at students.

We would like to thank all the authors who contributed and took part to make this special topic possible.