Completing a postal health questionnaire did not affect anxiety or related measures: randomized controlled trial

There is evidence from laboratory studies that anxiety scores are elevated by completing questionnaires about health problems for the first time. This limits interpretation of the common finding that people receiving risk information from screening programs show elevated anxiety (as assessed by questionnaire) in the short-term, which subsides over time. We examine the extent to which postal questionnaire studies are affected by this potential measurement artifact.

Participants were 964 patients at high risk of undiagnosed diabetes, registered at five general practices. A two-group randomized experimental design was used, with the experimental group (n=484) receiving an initial questionnaire concerning screening for diabetes, and the control group (n=480) not receiving this questionnaire. Outcomes were assessed by an identical questionnaire 3 months later.

There were no significant differences in questionnaire scores at three months between the two groups on any of the outcome measures, including anxiety, symptoms, perceptions of diabetes severity, and perceived diabetes risk.

These results suggest that the problems associated with the use of anxiety questionnaires that are found in laboratory studies do not occur in postal studies: the observed changes in anxiety after receiving screening results are therefore unlikely to be artifactual.