“Surfing the internet can expose a 'dark side' of the soul, with online addicts more likely to be depressed,” the Daily Mail reported. It said that research has found that the worst affected were depressed and addicted “possibly because they are substituting the net for normal social activities”.

This study questioned 1,319 users of social networking sites on their internet use and their depressive symptoms. Although it found an association between the two, this does not prove causation. It’s possible that a person uses the internet more because they are depressed, not the other way around. Other limitations include the fact that only 18 people were ‘addicted’, and the questionnaires assessing their depressive symptoms are not a diagnosis of depression on their own.

A link between depression and internet addiction is not out of the question. There are established links between depression and other addictive behaviours, such as gambling and alcoholism. However, the suggestion of a causal relationship will need further research, as will the implication that social isolation caused by internet addiction might contribute.

Where did the story come from?

The research was carried out by Catriona Morrison and Helen Gore from the Institute of Psychological Science, at the University of Leeds. No sources of funding are reported. The study was published in the peer-reviewed medical journal, Psychopathology .

In general, the news stories represented this study fairly but the strong link reported by several papers is not supported by this single study alone.

What kind of research was this?

This cross-sectional study explored the possibility that internet addiction, like other addictions, may be linked to depression. Internet addiction is defined in this study as “an individual’s inability to control their internet use, which in turn leads to feelings of distress and functional impairment of daily activities”.

A cross-sectional study such as this can only find associations between variables. It cannot prove causation. It is possible that a person will use the internet more often because they have become depressed and withdrawn, not the other way round. A cross-sectional study, provided it is of adequate size, could indicate the prevalence of both depression and internet addiction in the community. However, it would need to examine a representative sample of the population and to have used accurate methods for diagnosing both conditions.

What did the research involve?

For this study, 1,319 people were recruited through advertisements placed on social networking sites. The average age of participants was 21 years (range 16 to 51) and 63% were female. Participants were all users of social networking sites and completed three online questionnaires. They were:

Young’s Internet Addiction Test, which asks 20 questions to measure a person’s internet use and scores them on a 100-point scale as mildly, moderately or severely addicted.

The Internet Function Questionnaire, which assesses the nature of their internet use (eg shopping sites, chat, email, research, etc) and the time spent on each.

Beck Depression Inventory (BDI), which is a well-established self-assessment tool for depression.

The authors then looked at relationships between the internet dependence, types of use and depression.

These are all validated questionnaires. However, as they were all self-completed there is likely to be a degree of inaccuracy introduced.

The researchers were also not able to examine the wider personal, social, professional and health circumstances of participants, which are likely to be the main influence on mental health. In any case, a single questionnaire assessment cannot be taken as a definite diagnosis of addiction or depression.

What were the basic results?

There was a close correlation between addictive tendencies and depression across the sample, with the higher the depression score, the higher the addiction score. Men showed more addictive tendencies than women, and younger people more than older people.

Of the total sample, 18 or 1.2% were considered to have internet addiction. Compared to age- and sex-matched addicted people, the non-addicted group were firmly in the non-depressed symptom range, while those addicted were in the moderate-to-severely depressed range.

There was also a difference in type of internet use, with the addicted group looking at more sexually gratifying websites, gaming websites and online community/chat websites than the non-addicted group.

How did the researchers interpret the results?

The authors conclude that the concept of internet addiction “is emerging as a construct that must be taken seriously” and “those who regard themselves as dependent on the internet report high levels of depressive symptoms”. The authors say that further work is needed on assessing this relationship.

Conclusion

The study has several limitations and cannot prove that using the internet can lead to depression as reported in several newspapers:

Cross-sectional studies can only investigate associations between variables because they cannot establish the temporal relationship between them, ie which happened first. It is possible that people use the internet more often because they are already depressed and withdrawn, not the other way round.

The sample was not representative of UK internet users in general. Recruitment took place through social-networking sites, which older people tend not to use, and therefore has sampled a predominantly younger population with an average age of 21.

Although the study used validated questionnaires to examine the outcomes of interest, all were self-completed so there may be some unavoidable inaccuracy. Also, a single questionnaire assessment cannot be taken as a definite diagnosis of either addiction or depression.

The study has not been able to examine the wider personal, social, professional and health circumstances of the participants, and it is these factors that are likely to be the main influence on an individual’s mental health.

Only 18 people were considered to have internet addiction, so examining associations between other factors in this small number of people is likely to involve some inaccuracy.

An association between depression and internet addiction is not out of the question. There are well-established links between depression and other addictive behaviours, such as gambling, drug addiction and alcoholism. However, the suggestion of a causal relationship will need further research, as will the implication that social isolation caused by internet addiction might contribute.

Analysis by Bazian

Edited by NHS Website