Reduced vmPFC volume mediates the association between early exposure to family material hardship and problematic mobile phone use: The moderating role of parental attachment

Early exposure to family material hardship is an essential risk for problematic mobile phone use (PMPU). However, less is known about the reason for the association between early material hardship and PMPU. One possibility is that early hardship is a stressor that negatively affects brain structure, increasing the risk for PMPU. In testing this model, we also took into account the possible mitigating effect of strong parent-child attachment in this risk process. Participants were 45 young adults aged 18 to 23 years old who completed questionnaires to assess early material hardship, PMPU, and parental attachment. Deficits in brain structure were measured by estimating grey matter volume (GMV) using a voxel-based morphometry method via structural magnetic resonance imaging. Results revealed a significant association between early exposure to family material hardship and decreased GMV in right ventromedial prefrontal cortex (vmPFC), left orbital inferior frontal cortex (orbIFC) and left middle cingulate cortex (MCC). Importantly, subsequent structural equation modeling showed that decreased GMV within vmPFC fully mediated the association between high family material hardship and PMPU. Furthermore, stronger parental attachment mitigated the risk of decreases in vmPFC volume on PMPU following early exposure to family material hardship.