Reliability and validity of a self-report scale for daily assessments of the severity of anxiety symptoms.

BACKGROUND: To evaluate the efficacy of rapidly effective treatments it is necessary to use measures that are designed to assess symptom severity over short intervals. In the present report from the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project, we modified our previously published anxiety scale and examined the reliability and validity of a daily version of the Clinically Useful Anxiety Outcome Scale (CUXOS-D, D indicates daily version).

METHODS: Two thousand four hundred and ninety-one patients presenting for treatment to a partial hospital program completed the CUXOS-D as part of their initial paperwork and on a daily basis thereafter. Test-retest reliability was examined in 50 patients who completed the CUXOS-D twice on the same day. A subset of 73 patients was interviewed by a trained rater who administered the Hamilton Anxiety Rating Scale (HAMA) at baseline and on the day of discharge.

RESULTS: The CUXOS-D had high internal consistency and test-retest reliability and was more highly correlated with another measure of anxiety symptoms than depressive symptoms. CUXOS-D scores progressively declined during the course of treatment, and scores on each successive day were significantly lower than the preceding day. The change in CUXOS-D scores was significantly correlated with a change in HAMA scores (r = 0.61, p < .001). A large effect size was found for both measures (CUXOS-D: d = 1.22; HAMA: d = 0.93).

DISCUSSION: In a large sample of partial hospital patients mostly diagnosed with mood and anxiety disorders, we demonstrated some aspects of the reliability and validity of the CUXOS-D.