Abstract

BACKGROUND:

This study examined the efficacy and tolerability of duloxetine and venlafaxine extended-release (XR) treatment for generalized anxiety disorder (GAD), with a secondary focus on psychic and somatic symptoms within GAD.

METHOD:

The design was a 10-week, multi-center, double-blind placebo-controlled study of duloxetine (20 mg or 60-120 mg once daily) and venlafaxine XR (75-225 mg once daily) treatment. Efficacy was measured using the Hamilton Anxiety Rating Scale (HAMA), which includes psychic and somatic factor scores. Tolerability was measured by occurrence of treatment-emergent adverse events (TEAEs) and discontinuation rates.

RESULTS:

Adult out-patients (mean age 42.8 years; 57.1% women) with DSM-IV-defined GAD were randomly assigned to placebo (n=170), duloxetine 20 mg (n=84), duloxetine 60-120 mg (n=158) or venlafaxine XR 75-225 mg (n=169) treatment. Each of the three active treatment groups had significantly greater improvements on HAMA total score from baseline to endpoint compared with placebo (p=0.01-0.001). For the HAMA psychic factor score, both duloxetine treatment arms and venlafaxine XR demonstrated significantly greater improvement compared with placebo (p=0.01-0.001). For the HAMA somatic factor score, the mean improvement in the duloxetine 60-120 mg and venlafaxine XR groups was significantly greater than placebo (p0.05 and p0.01 respectively), whose mean improvement did not differ from the duloxetine 20 mg group (p=0.07). Groups did not differ in study discontinuation rate due to adverse events.

CONCLUSIONS:

Duloxetine and venlafaxine treatment were each efficacious for improvement of core psychic anxiety symptoms and associated somatic symptoms for adults with GAD.