Problematic smartphone use is related to depression and anxiety: A transdiagnostic and three-sample network analysis.

Problematic smartphone use (PSU) is associated with depression and anxiety disorders. However, it remains unclear which PSU symptoms are the most important contributors to depression, anxiety, and their comorbidity. Therefore, we examined the symptom-level network of PSU and separate and comorbid depression and anxiety. Three regularized partial-correlation networks were estimated for each sample, including the PSU-depression-anxiety (P-D-A), PSU-depression (P-D), and PSU-anxiety (P-A) networks. Three independent Chinese samples encompassing 325 aged 18-36 years, 1047 aged 18-26 years, and 988 aged 18-40 years were recruited in 2022, 2023, and 2024, respectively. PSU, depression, and anxiety were assessed using Smartphone Application-Based Addiction Scale, Patient Health Questionnaire-9, and Generalized Anxiety Disorder-7, respectively. Centrality and bridge centrality indices were estimated, and network comparison tests (NCTs) were performed to compare the networks of the three samples pairwise. NCTs revealed comparable network structures and consistent roles of specific symptoms across three samples. In P-D-A networks, PSU symptom "relapse" and depression symptom "depressed or sad mood" consistently had the highest centrality, whereas PSU symptom "conflict" consistently presented the highest bridge centrality. In P-D networks, the central nodes were identical to those observed in the P-D-A networks. In P-A networks, PSU symptom "relapse" and anxiety symptom "uncontrollable worry" consistently functioned as the central nodes. These findings elucidated the consistent and central role of "relapse" in the development and maintenance of depression, anxiety, and their comorbidity, thus establishing its roles as transdiagnostic risk factor. Furthermore, the results showed that PSU symptom "conflict" was the bridge node responsible for comorbidity. The replicability of these findings was confirmed, and their implications were thoroughly discussed.