Researchers in China who compared the brain scans of 18 teenagers diagnosed with Internet Addiction Disorder (IAD) with those of 18 non-addicted teenagers found differences in white matter density in over 20 brain regions. A report on their findings was published online in the 11 January issue of PLoS ONE.
All the participants had a brain scan from which the researchers assessed the density and structure of the white matter. White matter contains fibers that carry the signals various parts of the brain use to communicate with each another.
The researchers, who came from the Chinese Academy of Sciences and other research centers in China, also assessed a range of behavioral features such as addiction, anxiety, emotional disorder, social relationships, family functioning and time management and compared the results from the group diagnosed with IAD with the non-IAD group.
They found the participants in the IAD group performed less well in some of the behavioral assessments, including an additional measure of addiction, a questionnaire that assesses emotional conduct and problems in relationships, and a measure that screens for anxiety-related emotional disorders.
Also, when the researchers compared brain regions they observed to be different between the groups with the results of their behavioral assessments, they found that worse (ie less "healthy") scores on two of the behavioral measures were linked to lower white matter density in two specific brain regions.
The researchers conclude that their findings show IAD is "characterised by impairment of white matter fibres connecting brain regions involved in emotional generation and processing, executive attention, decision making and cognitive control".
At this point we might mistakenly assume that because the researchers found a link between IAD and brain changes, that it was the former that led to the latter.
However, we should bear in mind that this is a a cross-sectional study: the researchers took a "snapshot" at one point in time. They did not follow the participants over a period and they did not establish what their brain structures were like before they became "addicted" to the internet. So we don't know if the brain changes were already present beforehand and so we can't rule out whether they led to or contributed to the addiction.
There are two other reasons to be cautious about interpreting these results:
Firstly, the number of participants is small, and while the results may show "statistical significance", we should probably regard them as tentative.
Secondly, internet addiction is a relatively new disorder, and while more studies are appearing using the term, it is not clearly defined and universally recognized. For instance it is not included in the current edition of the "bible" of psychological disorders, the Diagnostic and Statistical Manual of Mental Disorders (DSM-V).
However, judging from the reactions of other experts interviewed by the media this week, it appears the findings are intriguing enough to warrant further research, using larger groups, and comparing for example, participants with IAD with everyday internet users who do not have IAD.
In this study, participants were assessed as having IAD if they answered yes to the first five of the following questions and also one of the remaining three questions (there were other items in the questionnaire):
- Do you feel preoccupied with the internet (that is, think about previous online activity or anticipate your next online session)?
- Do you feel the need to use the internet for increasing amounts of time in order to achieve satisfaction?
- Have you repeatedly made unsuccessful efforts to control, cut back or stop internet use?
- Do you feel restless, moody, depressed or irritable when attempting to cut down or stop internet use?
- Do you stay online longer than originally intended?
- Have you jeopardised or risked the loss of a significant relationship, job, educational or career opportunity because of the internet?
- Have you lied to family members, a therapist or others to conceal the extent of involvement with the internet?
- Do you use the internet as a way of escaping from problems or of relieving a distressed mood (for example, feelings of helplessness, guilt, anxiety and depression)?
Written by Catharine Paddock PhD