Internet addiction associated with altered brain connectivity in teens

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Excessive internet use has become a major problem in recent years, and a recent study published in PLOS Mental Health has provided new insights into how this phenomenon might correlate with changes in the developing adolescent brain. The study, which reviewed multiple research findings, suggests that internet addiction is associated with altered functional connectivity across multiple brain networks in adolescents.

Adolescence is a critical period characterized by significant biological, cognitive, and social changes. Given the heightened neuronal plasticity and risk-taking behavior during this phase, understanding how excessive internet use correlates with brain connectivity may provide insight into both potential consequences and interventions for internet addiction. The study aimed to answer an important question: how internet addiction correlates with functional connectivity in the adolescent brain.

“My interest in this topic was sparked by my experience of playing video games and using the internet growing up. When I was given the opportunity to explore this interesting and relevant topic, I jumped at the chance to investigate it,” said study author Max LY Chang, who conducted the research at University College London.

The researchers conducted a meta-analysis to examine the neurological changes associated with internet addiction in adolescents. A meta-analysis is a statistical technique that combines the results of multiple scientific studies to gain a more comprehensive understanding of a specific research question.

By synthesizing data from multiple studies, meta-analyses can identify patterns, assess the robustness of findings, and produce more generalizable conclusions. This approach is particularly useful in areas where individual studies may have small sample sizes or varying results, as it helps mitigate these limitations and produce a clearer overall picture.

For this meta-analysis, the researchers adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, which ensure a structured and transparent review process. They systematically searched databases such as PubMed and PsycINFO for studies involving adolescents aged 10 to 19 years with a clinical diagnosis of Internet addiction.

The inclusion criteria for the studies were: participants with a clinical diagnosis of internet addiction, use of imaging techniques such as functional magnetic resonance imaging (fMRI), peer-reviewed publications written in English, and studies published between January 2013 and April 2023. Studies that did not meet these criteria were excluded.

After an initial search yielded 238 articles, the researchers applied their inclusion and exclusion criteria to narrow the pool down to 12 eligible studies. These selected studies were primarily from Asian countries, specifically China, Korea, and Indonesia, and included sample sizes ranging from 12 to 31 participants. The studies used various fMRI techniques to examine the functional connectivity of the brain.

The findings indicated that Internet addiction is associated with altered connectivity in the default mode network (DMN) and the reward network. The DMN, which is involved in self-referential and attentional processes, showed both increases and decreases in functional connectivity, depending on the specific brain region.

For example, the posterior cingulate cortex, a crucial component of the DMN, showed altered connectivity patterns in adolescents with Internet addiction. In addition, increased connectivity was observed in regions linked to the reward system, such as the nucleus accumbens and caudate, suggesting increased reinforcement for Internet-related stimuli.

The executive control network (ECN), which is critical for cognitive functions such as response inhibition and emotional regulation, showed consistent reductions in functional connectivity. Adolescents with Internet addiction showed reduced connectivity in regions such as the dorsolateral prefrontal cortex and inferior frontal gyrus, which are critical for controlling impulsive behavior. These changes suggest that impaired executive control may contribute to compulsive Internet use, even in the face of negative consequences.

The salience network (SN), responsible for identifying and responding to important stimuli, also showed moderate decreases in connectivity. Reduced structural connectivity and fractional anisotropy in the SN were correlated with impaired cognitive control across tasks. These findings suggest that adolescents with Internet addiction may have difficulty effectively managing their attention and responses to Internet-related cues.

The study’s findings highlight similarities between Internet addiction and other forms of behavioral and substance addiction, such as gambling and drug addiction. The increased connectivity in the reward network and decreased connectivity in the executive control network are patterns that are often observed across different types of addiction. This suggests that similar neural mechanisms may underlie different addictive behaviors.

“The main takeaway I hope people take away from this review is that adolescents with internet addiction show changes in their brains that can profoundly impact their development and behavior,” Chang told PsyPost. “But with this conclusion, it’s important to understand that the internet is not an all-good or all-bad entity.”

“For Internet addiction, many of the underlying mechanisms are largely unknown. My hope for this field is that in the future we will develop a comprehensive understanding of the causes and effects of Internet addiction.”

Although the study provides valuable insights, it also has some limitations. The reviewed studies were mainly from Asian countries, which raises questions about the generalizability of the findings to other populations. Furthermore, the small sample sizes of the included studies may affect the reliability and applicability of the results. Most studies used cross-sectional designs, which makes it difficult to establish causal relationships between Internet addiction and changes in brain connectivity.

“While this paper presents a simple systematic review suggesting that there are links between functional connectivity in the brain and internet addiction, there are a number of fundamental limitations we need to be aware of that are critical to any interpretation,” Professor David Ellis, from the University of Bath’s Institute for Digital Security and Behaviour, told the Science Media Centre.

“First, the causal language used throughout is misleading. For example, headlines such as ‘How does Internet addiction affect functional connectivity’ and the suggestion of ‘effects’ throughout are incorrect. Cause and effect cannot be inferred from these studies, but this is only highlighted in the discussion as an important limitation.”

“Second, the focus on functional connectivity comes at the expense of critique of the primary measure of interest,” Ellis continued. “Specifically, Internet ‘addiction,’ which was initially coined as a joke by Ivan K. Goldberg in 1995. Today, the conceptualization and measurement of Internet ‘addiction’ is neither universally accepted nor diagnosable using the survey instruments used in the studies included in the review. Likewise, the enormity of the activities that the Internet enables immediately renders this definition somewhat redundant.”

“Such definitions, despite widespread criticism, also tend to shift the focus from real online harms to a conclusion that suggests removing technology from people’s lives will be beneficial. Solid evidence suggesting that removing the internet brings tangible benefits has not been provided.”

“What we do know is that self-reported ‘addiction’ measures, such as those used in the papers reviewed here, appear to capture something about how much someone worries in general. We have repeatedly noted that surveys used to assess related ‘addictions’ measure a poorly defined construct that sometimes overlaps with existing measures of well-being. More importantly, these assessments are weakly associated with the actual time someone spends using digital technologies, including the internet.”

“This means that any associations between functional connectivity and Internet addiction are dependent on multiple cofounders. This makes drawing strong conclusions from the reviewed papers nearly impossible,” Ellis concluded.

The study, “Functional Connectivity Alterations in the Brains of Adolescents with Internet Addiction: A Systematic Literature Review of Imaging Studies,” was authored by Max LY Chang and Irene O. Lee.

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