OBJECTIVES: Fast-acting medications for the management of anxiety are important to patients. Measuring early onset, however, requires a sensitive and clinically responsive measure. The goals of this study were to evaluate aspects of psychometric properties of a Global Anxiety-Visual Analogue Scale (GA-VAS) and its ability to detect reduction of anxiety symptoms during the first week of treatment.
METHODS: A 4-week, double-blind, randomized, multicenter, fixed dose, placebo-controlled, parallel group study of lorazepam and paroxetine in patients with Generalized Anxiety Disorder (GAD) was undertaken to assess the GA-VAS. The GA-VAS was administered at screening, during the active treatment phase, and at the closeout visit. In addition, the GA-VAS was completed each night during the first week of treatment. A comprehensive evaluation of the reliability, validity, and responsiveness of the GA-VAS was undertaken.
RESULTS: Lorazepam was chosen as a potentially fast-acting benzodiazepine, and separated from placebo at Week 1 on the Hamilton Anxiety (HAM-A) scale and at Study Day 2 (24 hours after first dose) on the GA-VAS. Paroxetine, a selective serotonin reuptake inhibitor (SSRI), was chosen as slower-acting GAD pharmacotherapy, and separated from placebo at Week 2 on both the HAM-A and GA-VAS. For a single item, the GA-VAS has adequate 24-hour test-retest reliability, with a reliability coefficient ranging from 0.50 to 0.60, and correlates well with other established measures of anxiety and quality of life. At Week 4, r = 0.60 (p<0.0001) with the HAM-A and r = 0.74 (p<0.0001) with the Hospital Anxiety and Depression Scale-Anxiety Subscale (HADS-A). In terms of convergent and divergent validity, the GA-VAS correlated −0.54 (p<0.0001), −0.48 ( p<0.0001), and −0.68 ( p<0.0001) with the Medical Outcomes Study Short Form-36 (SF-36) Emotional Role, Social Function, and Mental Health subscales, respectively, but correlated −0.24 (p<0.01), −0.26 (p<0.01), and −0.31 (p<0.001) with the SF-36 Physical Function, Bodily Pain, and Physical Role subscales, respectively. Preliminary minimally clinically important difference (MCID) estimates range from about 10 mm to 15.5 mm.
CONCLUSIONS: This study demonstrates the ability of the GA-VAS to validly and effectively capture a reduction in anxiety symptoms as quickly as 24 hours post-dose.
