Microstructure abnormalities in adolescents with internet addiction disorder

Abstract

Background: Recent studies suggest that internet addiction disorder (IAD) is associated with structural abnormalities in brain gray matter. However, few studies have investigated the effects of internet addiction on the microstructural integrity of major neuronal fiber pathways, and almost no studies have assessed the microstructural changes with the duration of internet addiction.

Methodology/principal findings: We investigated the morphology of the brain in adolescents with IAD (N = 18) using an optimized voxel-based morphometry (VBM) technique, and studied the white matter fractional anisotropy (FA) changes using the diffusion tensor imaging (DTI) method, linking these brain structural measures to the duration of IAD. We provided evidences demonstrating the multiple structural changes of the brain in IAD subjects. VBM results indicated the decreased gray matter volume in the bilateral dorsolateral prefrontal cortex (DLPFC), the supplementary motor area (SMA), the orbitofrontal cortex (OFC), the cerebellum and the left rostral ACC (rACC). DTI analysis revealed the enhanced FA value of the left posterior limb of the internal capsule (PLIC) and reduced FA value in the white matter within the right parahippocampal gyrus (PHG). Gray matter volumes of the DLPFC, rACC, SMA, and white matter FA changes of the PLIC were significantly correlated with the duration of internet addiction in the adolescents with IAD.

Conclusions: Our results suggested that long-term internet addiction would result in brain structural alterations, which probably contributed to chronic dysfunction in subjects with IAD. The current study may shed further light on the potential brain effects of IAD.

Figure 1. VBM results.

A. Reduced gray matter volume in IAD subjects, (1-p) corrected p-value images. The background image is the standard MNI152_T1_1mm_brain template in FSL. B. The gray matter volumes of the DLPFC, rACC and SMA were negatively correlated with the duration of internet addiction.

Figure 2. DTI results.

A. White matter structures showing abnormal FA in IAD subjects, (1-p) corrected p-value images. The background image is the standard FMRIB58_FA_1mm template in FSL. Red-Yellow voxels represent regions in which FA was decreased significantly in IAD relative to healthy controls. Blue-Light Blue voxels represent increased FA in IAD. B. The FA of the PLIC was positively correlated with the duration of internet addiction.