Dr Shock covers a new study examining the validity of one of the most popular methods for diagnosing ‘internet addiction’, Young‚Äôs Diagnostic Questionnaire, finding it lacks even the most basic ability to distinguish between frequent and infrequent net users.
Validity is one of the essential components of a psychological measure. It refers to whether it is actually measuring what it says it’s measuring.
One of the most common ways of testing validity is to see whether the scale predicts other aspects of behaviour or psychological functioning that we would expect would go along with the target behaviour.
In this case, we would expect ‘internet addicts’, as identified by a cut-off score on the Young’s Diagnostic Questionnaire, to spend more time on line than ‘non-addicts’, have greater levels of mental distress or behavioural impairment and would be more focused on specific internet activities.
Two psychologists, Nicki Dowling and Kelly Quirk, set out to test this on over 400 students – a group who have been previously highlighted as likely to be vulnerable to excessive internet use.
They found that those students who were clearly identified by the questionnaire as ‘internet addicts’ were no different in time spent online or psychological dysfunction from those students who were just below the cut-off.
What they did find, however, is those students who ticked zero to two items, the lowest ‘risk’ category, on the 8-item questionnaire typically used the internet for fewer hours and were likely to be depressed or anxious than the people who scored above the ‘addiction’ cut-off.
However, as three of the diagnostic items specifically refer to spending longer time online, and three specifically refer to low mood, anxiety or preoccupation, this is hardly surprising.
It’s like finding out people who say they are sad are more likely to be depressed.
What the study did clearly show, however, is that the criteria for distinguishing ‘addicts’ from ‘non-addicts’, which has been the basis of the majority of ‘internet addiction’ research, doesn’t even reliably distinguish between amount of use and psychological distress.
This is important, because the criteria have been offered by proponents as the basis of a possible ‘internet addiction’ diagnosis in the forthcoming updated psychiatric diagnostic manual, the DSM-IV.
This comes only a few weeks after a recent study reported the damning conclusion that previous studies used “inconsistent criteria”, where subject to “serious sampling bias” and usually reported associations rather than doing any sort of work on causal influences.