We all know that the internet can be a powerful tool—but for some teens, it can become something they can’t live without. A recent scientific review in 2024 looked at how internet addiction affects the brains of teenagers. What the researchers found is both fascinating and concerning.
This blog post will walk you through what the study discovered, what parts of the brain are involved, and how constant screen time may change the way a teen’s brain works. Most importantly, we’ll break it down in simple terms so that anyone can understand what’s going on inside the mind of someone who’s hooked on the internet.
What Was the Study About?
The study, published in PLOS Mental Health, reviewed 12 brain imaging studies that focused on adolescents ages 10–19 who were diagnosed with Internet Addiction (IA). These teens often had trouble staying off their phones, video games, or other online platforms—even when they wanted to.
The scientists used fMRI scans (functional magnetic resonance imaging), which allow researchers to see how different parts of the brain “talk” to each other while at rest or during tasks. The goal was to find out which brain systems are different in teens who show signs of internet addiction.
The Brain Systems Involved
Default Mode Network (DMN)
What the DMN Does:
The Default Mode Network is active when the brain is at rest—not focused on the outside world. It’s involved in:
- Self-reflection
- Daydreaming and imagination
- Memory recall
- Thinking about others (social cognition)
Main Brain Structures in the DMN:
- Medial Prefrontal Cortex (mPFC)
- Posterior Cingulate Cortex (PCC)
- Inferior Parietal Lobule
- Anterior Insula Cortex
- Cerebellum
- Middle Temporal Gyrus
- Putamen
How Internet Addiction Affects the DMN:
- The review found mixed changes in functional connectivity (FC) within the DMN.
- Some studies showed increased connectivity, especially in the precuneus and posterior cingulate cortex—areas linked to self-focus and internal thoughts.
- Other studies found reduced connectivity between the DMN and prefrontal areas.
- These disruptions may reflect excessive internal processing, such as constant rumination about digital content (e.g., game strategies, social media), or difficulty disengaging from online mental states.
- Teens with IA may spend more time “in their heads” and less time being fully present, leading to reduced attention to the real world.
Executive Control Network (ECN)
What the ECN Does:
The Executive Control Network is responsible for goal-directed behavior, especially:
- Planning and organizing
- Inhibiting impulses
- Maintaining attention and focus
- Problem-solving
Main Brain Structures in the ECN:
- Dorsolateral Prefrontal Cortex (DLPFC)
- Anterior Insula Cortex
- Inferior Frontal Gyrus
How Internet Addiction Affects the ECN:
- Studies in the review showed reduced functional connectivity in the ECN among adolescents with Internet Addiction.
- Especially in the DLPFC, which plays a central role in resisting distractions and making decisions.
- This weakened connectivity is linked to:
- Impaired impulse control
- Difficulty regulating digital usage
- Struggles with focus and cognitive flexibility
- Essentially, the brain’s “braking system” is weakened, making it harder for teens to stop or moderate internet use—even when they know they should.
Salience Network (SN)
What the SN Does:
The Salience Network acts as the brain’s switchboard, helping to:
- Detect what is important (salient)—internally or externally
- Shift attention between the DMN and ECN
- Respond to emotional and sensory events
Main Brain Structures in the SN:
- Anterior Insula
- Dorsal Anterior Cingulate Cortex (dACC)
How Internet Addiction Affects the SN:
- The review found reduced functional connectivity within the SN in teens with IA.
- This includes less communication between the insula and dACC, key hubs for detecting and reacting to significant events.
- Impairments in this network can lead to:
- Difficulty shifting attention away from online content
- Overfocus on digital rewards (e.g., likes, game points)
- Underreaction to real-world cues, like school responsibilities or social interaction
- One study noted a 40% drop in connectivity between the SN and DMN, suggesting a weakened ability to switch between internal thoughts and external demands.
Summary Table
| Network | Normal Function | Affected Brain Areas | Effect of Internet Addiction |
|---|---|---|---|
| DMN | Self-reflection, memory, mind-wandering | mPFC, PCC, Inferior Parietal Lobule, Anterior Insula Cortex, Cerebellum, Middle Temporal Gyrus, Putamen | Mixed connectivity (↑ in precuneus, ↓ in mPFC); harder to shift focus from internal to external |
| ECN | Attention, planning, impulse control | DLPFC, Anterior Insula Cortex, Inferior Frontal Gyrus | Reduced FC; weakened decision-making and self-regulation |
| SN | Detects important stimuli, switches attention | Anterior Insula, dACC | Reduced FC; trouble shifting focus, poor emotional regulation |
What Does This Mean for Teens?
When these brain systems don’t work together like they should, it can cause real-life problems:
- Teens may struggle to focus in class or while doing homework.
- They may feel like they can’t stop scrolling, gaming, or checking notifications—even when it’s causing stress or conflict.
- They may be more impulsive, making choices without thinking them through.
- They might have a hard time enjoying things offline because their brain has become wired to crave digital rewards.
Are These Changes Permanent?
That’s a great question—and one the study couldn’t fully answer. Most of the research looked at a single point in time. That means we don’t yet know if these brain changes cause internet addiction, or if they’re the result of using the internet too much.
The good news? The teenage brain is still growing. That means there’s hope for healing. With the proper support—like therapy, boundaries, and digital detox—these patterns can often be improved or even reversed.
What Are the Limits of the Study?
While the results are eye-opening, the researchers pointed out a few limits:
- Most of the studies were done in Asia, especially South Korea and China. We don’t know if the results are the same for teens in other cultures.
- The sample sizes were small, meaning more research is needed to confirm the results.
- All the studies looked at snapshots in time. Long-term studies would help us better understand how these changes develop—or heal—over time.
Conclusion
This review gives us important insight into how internet addiction may affect the developing teenage brain. It shows that overuse of digital platforms can disrupt systems that control attention, self-control, and pleasure. The result is a brain that struggles to focus on real life—and constantly craves the next online hit.
As therapists, parents, educators, and life coaches, we need to take these findings seriously. Internet addiction isn’t just a habit—it can become a brain pattern that’s hard to break. But with early support and healthy habits, we can help teens regain control and build a more balanced relationship with technology.
Sources
Chang, Y. & Lee, S. (2024). Functional connectivity changes in the brain of adolescents with internet addiction: A systematic literature review of imaging studies. PLOS Mental Health, 1(2), e0000022. https://journals.plos.org/mentalhealth/article?id=10.1371/journal.pmen.0000022
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