The relationship between screen time and anxiety/depression symptoms in preschool children with autism spectrum disorder: the mediating role of cortical volume

Both screen time (ST) and the development of cortical volume have significant effects on the mental health of children. This study aims to examine the relationship between ST and mental health in preschool children with autism spectrum disorder (ASD) while investigating the potential mediating role of cortical volume. The findings may provide evidence to support clinical identification and intervention strategies. A retrospective observational analysis was conducted on 149 children with ASD aged 18–60 months, who were categorized into two groups based on their daily ST: high-dose exposure (HDE) and low-dose exposure (LDE). The study compared the two groups in terms of demographic characteristics, ASD symptoms, neurodevelopmental level, mental health condition (assessed using the Child Behavior Checklist, CBCL), and cortical volume. Pearson correlation tests were used to determine the direct correlations between ST, cortical volume, and mental health. Multi-step linear regression analysis was used to investigate the mediating effect of cortical volume on the association between ST and mental health conditions. Children in the HDE group showed significantly higher anxiety/depression scores (60.02 ± 28.76 vs. 50.17 ± 23.10, p = 0.03) and reduced cortical volume in the left superior frontal area (25,232.13 ± 3069.41 vs. 26,441.19 ± 3032.22, p = 0.02) compared to the LDE group. ST was positively correlated with anxiety/depression symptoms (r = 0.20, p = 0.02) and negatively correlated with the left superior frontal cortical volume (r= -0.29, p < 0.001). Furthermore, mediation analysis revealed that the cortical volume of the left superior frontal area fully mediated the relationship between ST and anxiety/depression symptoms. The findings suggest that ST adversely affects the mental health of children with ASD, with cortical volume in the left superior frontal area potentially serving as a key mediator in this relationship. These findings highlight the need for ST management in early ASD interventions. Chinese Clinical Trial Registry (ChiCTR): ChiCTR2100051141. Registered on 14 September 2021. [URL: http://www.chictr.org.cn]