Anxiety modulates the relationship between right inferior parietal lobule structure and problematic smartphone use: a test of the I-PACE model.

BACKGROUND

Problematic smartphone use (PSU) has been increasingly recognized as a behavioral addiction associated with heightened anxiety. According to the Interaction of Person-Affect-Cognition-Execution (I-PACE) model, affective factors such as anxiety may interact with individual neurobiological characteristics to facilitate and maintain problematic behaviors. However, the neurostructural mechanisms underlying the relationship between anxiety and PSU remain insufficiently understood.

METHODS

The Smartphone Application-Based Addiction Scale (SABAS) and the Generalized Anxiety Disorder-7 (GAD-7) were used to assess smartphone use severity and anxiety levels in the problematic smartphone use group and the healthy control group. Group differences in anxiety levels were first examined, followed by correlational analyses. Structural magnetic resonance imaging (sMRI) data were acquired, and voxel-based morphometry (VBM) was applied to identify brain regions associated with anxiety and problematic smartphone use. Within the problematic smartphone use group, moderation analyses were further conducted to examine whether anxiety moderated the relationship between gray matter volume in the identified regions and the severity of problematic smartphone use.

RESULTS

Individuals with problematic smartphone use exhibited significantly higher anxiety levels than healthy controls. Structural imaging analyses revealed three brain regions significantly associated with anxiety. Notably, within the PSU group, anxiety significantly moderated the relationship between gray matter volume of the right inferior parietal lobule (IPL) and problematic smartphone use severity. Specifically, alterations in the right IPL were more strongly associated with PSU under lower levels of anxiety.

CONCLUSIONS

These findings suggest that anxiety plays a critical modulatory role in the association between neurostructural alterations in the right inferior parietal lobule and problematic smartphone use. Consistent with the I-PACE model, affective vulnerability and brain structure jointly contribute to the development and maintenance of PSU. The right IPL may represent a key neural substrate linking anxiety-related cognitive control and attentional processes to maladaptive smartphone use behaviors.