The key finding
A 2025 systematic review analyzing 44 neuroimaging studies found that different types of internet addiction alter the brain’s reward processing circuits in distinctly different ways. Internet Gaming Disorder (IGD) is linked to widespread abnormalities in both the structure and function of reward network connections throughout the brain. In contrast, excessive social media use appears to primarily affect a more specific system—the amygdala-striatal pathway, which connects emotional processing centers to reward-seeking behaviors. These findings suggest that what we broadly call “internet addiction” may actually involve multiple distinct neurological patterns depending on the specific online activity.
What the study looked like
Researchers conducted a systematic review of 44 neuroimaging studies examining adult populations with various forms of internet addiction. The analysis focused on both structural brain imaging (showing physical connectivity between regions) and functional imaging (showing brain activity patterns during tasks). Studies were organized according to the Research Domain Criteria framework, which categorizes brain function into domains like reward processing. The review specifically examined three aspects of how the brain handles rewards: responsiveness (how strongly the brain reacts to rewarding stimuli), learning (how the brain updates predictions about rewards), and valuation (how the brain assigns worth to different options). The review included people with generalized internet addiction as well as specific subtypes like Internet Gaming Disorder and problematic social media use, allowing researchers to compare neural patterns across different types of internet-related behaviors.
Why researchers think this happened
The researchers propose that different internet activities engage reward systems through fundamentally different mechanisms. Gaming likely activates reward circuits through immediate, variable reinforcement schedules—leveling up, winning matches, and obtaining virtual rewards—which creates widespread changes across multiple interconnected reward regions. This mirrors patterns seen in substance and gambling addictions. Social media, however, may primarily hijack social reward pathways, particularly those involving the amygdala (which processes emotional significance) and striatum (which drives reward-seeking behavior). This distinction aligns with prior research showing that social feedback—likes, comments, and notifications—activates specific circuits evolved for social bonding and status. The review’s alignment with the RDoC framework suggests these different patterns reflect underlying differences in how various online behaviors exploit distinct evolutionary reward mechanisms, rather than representing a single unified disorder.
How to read this carefully
The review authors acknowledge significant methodological limitations that prevent definitive conclusions. Definitions of internet addiction varied considerably across the 44 studies, making direct comparisons challenging. Most studies used cross-sectional designs, which cannot establish whether brain differences caused internet addiction or resulted from it—the direction of causality remains unclear. Few studies directly compared different subtypes of internet addiction within the same research design, meaning the reported differences could partially reflect variations in study methods rather than true neurological distinctions. Additionally, the field lacks longitudinal research tracking how brain changes evolve over time with internet use. The authors emphasize these findings show correlations and associations, not proven causal mechanisms. Sample sizes and populations varied widely, and replication of specific findings remains limited.
What this means for everyday life
These findings suggest that managing different types of problematic internet use might benefit from different approaches, since the underlying brain patterns appear distinct. If you or someone you know struggles with gaming versus social media overuse, the neurological drivers may differ fundamentally. This might eventually inform more personalized interventions—for instance, treatments targeting emotional regulation might be especially relevant for social media concerns, while those addressing broader reward-system dysregulation might suit gaming issues better. However, given the methodological limitations, it’s premature to draw specific lifestyle recommendations. What this research does highlight is that lumping all “screen time” together oversimplifies the picture. The specific content and interaction patterns matter, potentially affecting our brains through different pathways. As research continues, understanding these distinctions could help individuals, families, and clinicians make more informed decisions about internet use patterns and interventions.