# Biomarkers of Internet Gaming Disorder—A Narrative Review

## TL;DR

This review explores biomarkers of Internet gaming disorder, focusing on brain regions and physiological responses linked to addiction and cognitive control.

## Contribution

The paper systematically categorizes IGD biomarkers and links them to theoretical addiction models, highlighting gaps and inconsistencies in current research.

## Key findings

- IGD is associated with hypersensitivity in the ventral striatum and reduced cognitive control in the prefrontal cortex.
- Biomarkers include altered P3 amplitudes, heart rate variability, and eye movement patterns during non-resting states.
- Some studies suggest a multimodal diagnostic model for IGD, though findings in regions like the NAcc and ACC remain inconsistent.

## Abstract

Since game mechanics and their visual aspects have become more and more addictive, there is concern about the growing prevalence of Internet gaming disorder (IGD). In the current narrative review, we searched PubMed and Google Scholar databases for the keywords “igd biomarker gaming” and terms related to biomarker modalities. The biomarkers we found are grouped into several categories based on a measurement method and are discussed in the light of theoretical addiction models (tripartite neurocognitive model, I-PACE). Both theories point to gaming-related problems with salience and inhibition. The first dysfunction makes an individual more susceptible to game stimuli (raised reward seeking), and the second negatively impacts resistance to these stimuli (decreased cognitive control). The IGD patients’ hypersensitivity to reward manifests mostly in ventral striatum (VS) measurements. However, there is also empirical support for a ventral-to-dorsal striatal shift and transition from goal-directed to habitual behaviors. The deficits in executive control are demonstrated in parameters related to the prefrontal cortex (PFC), especially the dorsolateral prefrontal cortex (DLPFC). In general, the connection of PFC with reward under cortex nuclei seems to be dysregulated. Other biomarkers include reduced P3 amplitudes, high-frequency heart rate variability (HRV), and the number of eye blinks and saccadic eye movements during the non-resting state. A few studies propose a diagnostic (multimodal) model of IGD. The current review also comments on inconsistencies in findings in the nucleus accumbens (NAcc), anterior cingulate cortex (ACC), and precuneus and makes suggestions for future IGD studies.