Mobile phones have become an important part of human life, with the development of global economy and society digitalization. As of April 2023, there were over 1.7 billion mobile phone subscriptions in China (Statista.com, 2023), and the penetration rate for mobile internet reached 99.8 % (CNNIC, 2022). Despite the convenience of mobile phones, concerns about problematic mobile phone use have emerged. Problematic mobile phone use refers to a cognitive, emotional and behavioral pattern of excessive use of mobile phones (Winkler et al., 2020). Many addiction-related (e.g., craving, loss of control, dependence, tolerance, withdrawal) and non-addictive symptoms (e.g., escapism) of problematic mobile phone use have been identified (Bianchi and Phillips, 2005, Billieux et al., 2015, Foerster et al., 2015, Panova and Carbonell, 2018). Adolescents are considered to be vulnerable to problematic mobile phone (Lopez-Fernandez et al., 2014, Yang et al., 2019). For instance, problematic mobile phone use has been detected in 50.6 % of the clinical adolescent sample (Firat et al., 2018). Previous studies have demonstrated that problematic mobile phone use is associated with serious physical and psychological consequences for adolescents, such as reduced physical fitness, poor sleep quality, poor academic performance, depression, anxiety, and suicide ideation (Arrivillaga et al., 2020, Elhai et al., 2017, Elhai et al., 2017, Firat et al., 2018, Hawi and Samaha, 2016, Ng et al., 2020). Therefore, it is important to continue to focus more broadly on problematic mobile phone use among adolescents.

Social anxiety as a common comorbid factor of problematic mobile phone use. Social anxiety is a state of anxiety resulting from the prospect or presence of interpersonal evaluation in real or imagined social setting, and consequently withdrawal in face-to-face social interactions (Leary, 1983, Valkenburg and Peter, 2009). Previous studies have found that social anxiety and problematic mobile phone use are highly positively correlated (Annoni et al., 2021, Lee et al., 2014, Turgeman et al., 2020). In particular, a meta-analysis showed that the association between social anxiety and problematic mobile phone use was stronger in adolescents than in adults (Ran et al., 2022). While previous studies have examined the relationship between social anxiety and problematic mobile phone use among adolescents, the relationship is rarely been explored by network analysis that may provide information from the inside structure. The present study utilized network analysis to enhance comprehension of the relationship between social anxiety and problematic mobile phone use among a sample of Chinese high school adolescents.

Network approaches may provide novel insights into the importance of specific symptoms within the structure of variables (Borsboom, 2008, Borsboom, 2017). According to the network theory, a mental disorder contains many symptoms that activate each other, and the disorder is the presentation of interactions between its constituent symptoms (Borsboom, 2008). Network analysis can provide information about disorders by investigating two aspects of the network.

First, network analysis can identify the central symptoms of a mental disorder by estimating the symptoms’ relative importance that reflects “the extent to which manipulating them may alter the functioning of the network” (Dablander & Hinne, 2019) (p.1). Studies have shown that one of the most important concerns associated with mobile phone use is “uncontrolled”, which has an impact upon daily living (Andrade et al., 2020, Billieux, 2012, Billieux et al., 2015). A study among students around 9–10 years and 13–14 years confirms the central role of “Loss of Control” in problematic mobile phone use by network analysis (Huang et al., 2021). For social anxiety, the fear of negative evaluation is considered to be the core feature of social anxiety (Auyeung et al., 2020, Weeks et al., 2008). That is, those with high social anxiety usually deem that others are likely to evaluate them negatively (Blöte et al., 2014, Leary, 1983). Previous studies have shown that cognitive factors play a central role within the network of social anxiety in children and adolescents (Miers et al., 2020, Vogel et al., 2021). A network analysis study found that the fear and avoidance of distinct social evaluative situations for individuals with social anxiety disorder (SAD) was more strongly interconnected than those without SAD (Heeren & McNally, 2017).

Second, in the network including two disorders, the bridge symptoms indicate diagnostic comorbidity, because activating bridge symptoms can spread issues to both disorders (McNally, 2016). The bridge symptoms refer to certain symptoms in one disorder could also activate symptoms in another one, which put people at risk for two disorders, and thereby produce diagnostic comorbidity (McNally, 2016). A study conducted during the COVID-19 pandemic found that after four mouths of online learning, “afraid of negative evaluation” and “withdrawal” were bridge symptoms between social anxiety and problematic mobile phone use among secondary school students (Tao et al., 2024). It is necessary to explore this issue after students return to normal study after COVID-19.

Taken together, identifying central symptoms and bridge symptoms through network analysis could contribute to understanding the core mechanisms underlying the disorders and developing effective interventions (Borsboom, 2017). The present study thus aims to enhance understanding of the comorbid relationship between social anxiety and problematic mobile phone use in Chinese adolescents through network analysis.

Based on social compensation theory, the limited audiovisual cues of mobile phones may help adolescents with social anxiety overcome the inhibitions they typically experience in real-life interactions (McKenna et al., 2002, Valkenburg and Peter, 2009). Using mobile phones allows adolescents with social anxiety to avoid face-to-face social interactions (Billieux et al., 2015). They use mobile phones as a means to protect themselves, seek security, and alleviate conflicts (King et al., 2013). As a result, adolescents with social anxiety may tend to believe that online conversation is a helpful coping strategy and a substitute for face-to-face social communication (Billieux et al., 2015, Ha et al., 2008). Some studies have found that higher levels of social anxiety are associated with more excessive mobile phone use and sending a greater number of text messages (Ha et al., 2008, Lee et al., 2014). In addition, mobile phones may provide adolescents with an ideal virtual world to relax and escape from the stress in the real world. Specifically, the use of mobile phone services, such as social networking sites and online gaming, was an adaptive response to cope with negative life situations, which could enable people with high in social anxiety to use the mobile phones (Kardefelt-Winther, 2014, Rozgonjuk et al., 2018). In the long term, adolescents who have their needs met through mobile phones may continue to use them more frequently. Indeed, numerous studies have demonstrated that social anxiety is associated with problematic mobile phone use (Annoni et al., 2021, Enez Darcin et al., 2016, Hong et al., 2019, Kong et al., 2021, Lee et al., 2014, Ran et al., 2022). Although literature has suggested the relationship between social anxiety and problematic mobile phone use, to our knowledge, rarely studies have used network analysis as a new approach to enhance comprehension of the relationships between the two disorders from the perspective of the inside structures.

The proponents of network analysis have suggested that psychopathology networks may vary over time and among individuals (Forbes et al., 2017). Analyzing the variations in network structure among different groups and at different time-points is beneficial for the targeted application of network analysis results.

The gender differences have been widely documented in the relevant literature regarding social anxiety and problematic mobile phone use. For instance, the types of mobile phone use may be different between boys and girls. Girls are more likely to use their mobile phones for social purposes (e.g., engaging in social networking, shopping, viewing TV shows) and are more susceptible to social media addiction, whereas boys are more prone to intensive use of mobile phones for gaming and are more vulnerable to internet gaming disorder (Bianchi and Phillips, 2005, Billieux et al., 2008, Lopez-Fernandez et al., 2017, Rio et al., 2017, Su et al., 2020). In addition, adolescent girls report higher levels of social anxiety than boys, including a greater fear of negative evaluation from peers and more social avoidance and distress in new situations among girls (Greca and Lopez, 1998, Tu et al., 2022). However, a three-level meta-analysis found no significant moderating effect of gender on the association between social anxiety and problematic mobile phone use (Ran et al., 2022). It is worth noting that studies analyzed in the meta-analysis are non-network analysis. It is of interest to explore whether the association between the two variables from the inside structures could be different between boys and girls through network comparison.

Given the potential dynamic development within the network (Bringmann et al., 2015, Forbes et al., 2017), it is crucial to examine how the network changes over time. To this end, the current study employed network analysis and network comparison to investigate the longitudinal features of the internal relationship between social anxiety and problematic mobile phone use over time.