Microstructural changes and internet addiction behaviour: A preliminary diffusion MRI study

Longer screen time utilization is associated with the polygenic risk for Attention-deficit/hyperactivity disorder with mediation by brain white matter microstructure

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) has been reported to be associated with longer screen time utilization (STU) at the behavioral level. However, whether there are shared neural links between ADHD symptoms and prolonged STU is not clear and has not been explored in a single large-scale dataset.

METHODS

Leveraging the genetics, neuroimaging and behavioral data of 11,000+ children aged 9-11 from the Adolescent Brain Cognitive Development cohort, this study investigates the associations between the polygenic risk and trait for ADHD, STU, and white matter microstructure through cross-sectionally and longitudinal analyses.

FINDINGS

Children with higher polygenic risk scores for ADHD tend to have longer STU and more severe ADHD symptoms. Fractional anisotropy (FA) values in several white matter tracts are negatively correlated with both the ADHD polygenic risk score and STU, including the inferior frontal-striatal tract, inferior frontal-occipital fasciculus, superior longitudinal fasciculus and corpus callosum. Most of these tracts are linked to visual-related functions. Longitudinal analyses indicate a directional effect of white matter microstructure on the ADHD scale, and a bi-directional effect between the ADHD scale and STU. Furthermore, reduction of FA in several white matter tracts mediates the association between the ADHD polygenic risk score and STU.

INTERPRETATION

These findings shed new light on the shared neural overlaps between ADHD symptoms and prolonged STU, and provide evidence that the polygenic risk for ADHD is related, via white matter microstructure and the ADHD trait, to STU.

FUNDING

This study was mainly supported by NSFC and National Key R&D Program of China.

Measurement of the problematic usage of the Internet unidimensional quasitrait continuum with item response theory

Problematic usage of the internet (PUI) describes maladaptive use of online resources and is recognized as a growing worldwide issue. Here, we refined the Internet Addiction Test (IAT) for use as a screening tool to measure generalized internet use problems in normative samples. Analysis of response data with parametric unidimensional item response theory identified 10 items of the IAT that measured most of the PUI latent trait continuum with high precision in a subsample of 816 participants with meaningful variance in internet use problems. Selected items may characterize minor, or early stages of, PUI by measuring a preoccupation with the Internet, motivations to use online activities to escape aversive emotional experiences and regulate mood, as well as secrecy, defensiveness, and interpersonal conflict associated with internet use. Summed scores on these 10 items demonstrated a strong correlation with full-length IAT scores and comparable, or better, convergence with measures of impulsivity and compulsivity. Proposed cut-off scores differentiated between individuals potentially at risk of developing PUI from those with few self-reported internet use problems with good sensitivity and specificity. Differential item function testing revealed measurement equivalence between the sexes, Caucasians and non-Caucasians. However, evidence for differential test functioning between independent samples drawn from South Africa and the United States of America suggests that raw scores cannot be meaningfully compared between different geographic regions. These findings have implications for conceptualization and measurement of PUI in normative samples.

We provide recommendations for measuring symptoms of problematic usage of the internet, which can be identified in a subset of the population using our refined version of the IAT and suggested cut-off scores. Relevant self-reported internet use problems include a preference for online over face-to-face social interactions, use of the internet to regulate emotions, excessive online engagement, interpersonal conflict, and emotional withdrawal following cessation of internet use.