Concordance between self-reported and observer-rated anxiety severity in outpatients with anxiety disorders: The Leiden routine outcome monitoring study

Objectives: Anxiety severity measures can be self-report or observer-rated. Although mostly these measures concur, they can diverge markedly. We examined concordance between two anxiety scales: the observer-rated Brief Anxiety Scale (BAS) and the self-report Brief Symptom Inventory 12-item version (BSI-12), and described associations between patient characteristics and discordance.

Design: The study used an observational design, using prospective data from 2,007 outpatients with DSM-IV-TR panic disorder with or without agoraphobia, agoraphobia without panic, social phobia, and/or generalized anxiety disorder.

Methods: Overall agreement was described using Pearson's product-moment correlation coefficient. Associations between patient characteristics and discordance (defined as |Z-BAS-Z-BSI-12| ≥ 1) were evaluated with univariable and multivariable multinomial logistic regression analyses.

Results: Overall correlation between BAS and BSI-12 was positive and strong (r = .59). Discordance occurred in 24.8% of patients ([Z-BAS ≥ Z-BSI-12 + 1] = 12.2%; [Z-BAS ≤ Z-BSI-12 - 1] = 12.6%). Patients with higher observed than self-reported anxiety severity did not differ from concordant patients. Patients with lower observed than self-reported anxiety severity more often had panic disorder, less often had social phobia, and had higher scores on cluster B and C personality characteristics than concordant patients. Lower observed than self-reported anxiety severity was best predicted by panic disorder, social phobia, and affective lability.

Conclusions: Results demonstrate that the use of a single source of information gives a one-sided view of pathology. A multimethod approach is highly preferable, as this allows for assessment across different domains and through multiple sources of information, and as such, provides clinicians with vital information.

Practitioner points: When assessing anxiety severity, the use of self-report measures provides additional information to observer-rated measures. In patients who have strong cluster B and C personality traits, anxiety severity might be overlooked, even by trained observers. The use of a multimethod assessment strategy is preferable in anxiety severity assessment.