Investigations of worry-based conditions like Generalised Anxiety Disorder often rely on trait questionnaires of worry like the Penn State Worry Questionnaire (PSWQ) and the Worry Domains Questionnaire (WDQ). Because these questionnaires are designed to gauge people's general worrying tendencies, rather than their actual worries. One concern is that a treatment might be found to lower scores on the PSWQ or WDQ, whilst not leading to a corresponding reduction in actual worrying.

A research team from the Netherlands and the USA have examined how well the following trait questionnaires: the PSWQ, the WDQ and the State-Trait Anxiety Inventory-Trait Form (STAI-T) predict the frequency and persistence of worry in people's lives. Four hundred and thirty-two undergraduate students completed these questionnaires before completing daily logs of their worries for six days.

The PSWQ is a 16-item self-report measure that asks about the excessiveness, duration and uncontrollability of worries with items like 'Once I start worrying, I can't stop'. The WDQ, by contrast, is a 25-item self-report questionnaire that focuses more on the content and amount of worry, with items like 'I worry that I will lose close friends'. The WDQ is arranged according to five subscales including relationships, lack of confidence and finances. The STAI-T measures participants' predisposition to worry, for example by asking whether they think they worry too much.

An immediate observation to come from the study was just how common worry was among this non-clinical population. It was found that participants were worrying an average of 23 minutes a day, and just two per cent of the sample reported not worrying at all for the six days' duration.

The PSWQ and WDQ, together with the STAI-T all correlated moderately with actual worry duration and worry frequency as judged from the logs, with the PSWQ being the most predictive in both cases. When scores from the questionnaires were entered into a regression analysis together, worry duration was best predicted by a combination of the PSWQ and WDQ (but not the STAI-T), while worry frequency was best predicted by a combination of all three measures. The PSWQ was the only measure that correlated with night-time worry.

Although these results support the validity of the questionnaires, the researchers noted that the correlations were modest, with the questionnaires accounting for approximately 24 percent of the variance of worry in daily life. The researchers suggest that the findings imply that the majority of the daily experience of worry is not predicted by trait measures. Writing in the journal Behaviour Research and Therapy, the researchers concluded that future studies assessing the emotional and health outcomes of worry should consider combining trait questionnaires with momentary assessments, for example diaries or logs.

Web Directions:

Verkuil, B., Brosschot, J.F. & Thayer, J.F. (2007). Capturing worry in daily life: Are trait questionnaires sufficient? Behaviour Research and Therapy, 45, 1835-1844.

Further reading:

The BMJ Best Treatments guide to tests of anxiety, including the Penn State Worry Questionnaire

Being a worrier could mean you live longer. This is from the British Psychological Society's Research Digest.

Where dread is located in the brain. This is a journal article.