Background: Duloxetine, a serotonergic noradrenergic reuptake inhibitor, improved functional outcomes in each of three clinical studies for the treatment of adults with generalized anxiety disorder (GAD). Using comparison norms, the current work describes the clinical relevance of these functional improvements in terms of return to normative functioning and symptom remission.
Methods: Data were pooled at the individual patient level from three double-blind, placebo-controlled trials of duloxetine treatment (9-10 weeks acute therapy, dose ranges 60-120mg). Inclusion/exclusion criteria were consistent across studies, and outcome measures included the Sheehan Disability Scale (SDS), Quality of Life Enjoyment and Satisfaction Questionnaire Short Form (Q-LES-Q-SF), and European Quality of Life 5 Dimensions (EQ-5D).
Results: Adult patients (mean age=42.4 years; 65% women) were randomly assigned to duloxetine (N=668) or placebo (N=495). At baseline, the majority of patients were impaired on the SDS global functioning (89%), Q-LES-Q-SF maximum percent (95%), and EQ-5D (76%) scores. On each measure, a greater percentage of duloxetine-treated patients converted from an impaired baseline to a normative endpoint score than did placebo-treated patients (p0.001, all comparisons). Remission defined as a HAMA total score at endpoint of 10, compared with 7, captured a greater proportion of patients who were functionally in remission.
Conclusions: GAD is associated with substantial impairment in functioning and subjective well-being, and patients treated with duloxetine 60-120mg/day, compared with placebo, experienced a greater return to normative functioning. Attention to role functioning and quality of life may refine our definition of remission when using standard symptom measures of anxiety.