In today’s hyperconnected society, smartphones have become indispensable tools for communication, learning, and entertainment. However, alongside these benefits, an expanding body of research has drawn attention to the risks associated with Problematic Mobile Phone Use (PMPU)—a behavioral pattern characterized by excessive and uncontrollable smartphone use that is closely associated with mental health (Sohn et al., 2019), although theoretical models often conceptualize psychological vulnerabilities as antecedents of such problematic use (Brand et al., 2019, Kardefelt-Winther, 2014). It is therefore plausible that the relationship between PMPU and mental health is bidirectional, involving both compensatory and consequential mechanisms. PMPU is particularly prevalent among university students and appears to be intensifying over time. A recent meta-analysis involving 23,387 Chinese university students revealed a substantial increase in PMPU scores over the past decade, rising from 36.55 to 46.25 (Huang et al., 2022). Similarly, a longitudinal comparison of Australian data collected between 2005 and 2018 showed that the average PMPU score in 2018 (M = 65.32, SD = 40.73) was significantly higher than that in 2005 (M = 57.08, SD = 30.66; Oviedo-Trespalacios et al., 2019). These findings underscore the urgent need to elucidate the underlying psychological mechanisms contributing to individual susceptibility to PMPU and to develop tailored, evidence-based interventions that address these contributing factors.

Among the psychological risk factors implicated in PMPU, alexithymia has emerged as a particularly salient yet understudied trait-level vulnerability. Alexithymia, a trait-level vulnerability involving emotional processing deficits (Bagby et al., 1994), has been consistently linked to maladaptive technology use. Although recent studies have reported a moderate association between alexithymia and PMPU (e.g., Darabiyan et al., 2024, Huang et al., 2022, Liang et al., 2024, Zhou et al., 2022), the majority have relied on aggregate-level analyses that assume emotional difficulties are experienced uniformly across individuals. Such an approach overlooks two critical gaps: first, that alexithymia is a multidimensional construct encompassing qualitatively distinct patterns of emotional processing; and second, that PMPU may result not from a single causal pathway, but from dynamic interactions among specific symptoms, such as craving, anxiety, and social withdrawal.

To address these limitations, the present study adopts a comprehensive, multi-level approach to examine both person-level heterogeneity and symptom-level mechanisms. Latent profile analysis (LPA) identifies heterogeneous subgroups of individuals based on emotional functioning, while psychological network analysis (PNA) models the interrelations among PMPU symptoms to reveal their core and bridging elements. Integrating PNA within the latent profiles derived from LPA allows the present study to examine how PMPU symptom structures differ across alexithymia subgroups and to clarify the mechanisms linking emotional dysregulation to maladaptive smartphone use. This combined approach offers a more refined, person- and symptom-centered understanding of PMPU and informs the development of tailored intervention strategies.