Generic effectiveness measures: sensitivity to symptom change in anxiety disorders

The purpose of this study was to compare a newly developed screening measure of disability, the WHODAS II, to three established generic effectiveness measures in terms of its sensitivity to symptom change in people with anxiety disorders.

Patients who had undergone treatment for social phobia or panic disorder/agoraphobia at an anxiety disorders clinic were administered generic effectiveness measures and symptom measures before and after treatment. The design was naturalistic and observational. Data analysis included correlations between generic effectiveness and symptom measures; and effect size calculations regarding the ability of each generic effectiveness measure to discriminate between patients whose symptoms improved and patients whose symptoms did not improve over the course of treatment.

The WHODAS II was consistently the most sensitive generic effectiveness measure in its capacity to detect symptom changes in patients with social phobia. The SF-12 and K-10 also showed moderate sensitivity to symptom change. In the sample of patients with panic disorder/agoraphobia, the SF-12 was the most sensitive measure overall, closely followed by the K-10 and WHODAS II. The NCS Disability Days were the least sensitive to symptom change in both samples.

The WHODAS II is at least as sensitive as other generic effectiveness measures to anxiety symptom changes, and is particularly sensitive to changes in social anxiety symptoms. It may prove to be a valuable measurement tool for informing public health policy in relation to anxiety disorders.