Duloxetine is more effective than placebo in improving daily function at home and at work in patients with generalized anxiety disorder, according to results from two studies presented at the annual meeting of the American Psychiatric Association. The improvements were due to decreases in anxious symptoms as well as improvements in associated painful physical symptoms.

Data from two double-blind, placebo-controlled trials in adults with generalized anxiety disorder were pooled (total number of patients, more than 840). In the first, 9-week, trial, patients received 60 mg or 120 mg once daily duloxetine or placebo. In the second trial, patients were started at 60 mg duloxetine but dose could be increased to 120 mg once daily; the other patients were randomized to placebo for the 10 weeks of prospective study.

In both trials, the Hamilton Anxiety Scale (HAMA) was used to measure anxious symptoms, the Sheehan Disability Scale was used to assess global functional impairment and the Visual Analog Scale for Overall Pain (VAS) was used to measure severity of painful physical symptoms.

Pearson partial correlations were used to assess the magnitude and significance of the associations between global functional impairment and psychic anxiety or painful physical symptoms. Path analysis was used to assess the relative contributions of changes in psychic and somatic anxiety and painful physical symptoms on improved functional outcomes.

In the first study, patients treated with 60 mg or 120 mg daily had statistically significant improvements compared with patients treated with placebo as defined by mean change in scale score (7.76 and 7.04 vs. 3.83). In the second study, patients treated with 60-120 mg daily had statistically significant improvements compared with patients treated with placebo defined by mean change on scale score (5.78 vs. 3.11).

In the pooled analysis, among duloxetine-treated patients, 48 percent of improvement in global functioning was from improvements in psychic anxiety, while 9 percent was from improvements in painful physical symptoms and 7 percent was from improvements in somatic anxiety.

"This study underscores the importance of treating all of the many symptoms of generalized anxiety disorder and reducing the global functional impairment associated with the disorder," said David Sheehan, MD, lead study author and professor of psychiatry at the University of South Florida College of Medicine in Tampa. "This information may be important for physicians to consider when choosing a treatment for their patients with generalized anxiety disorder since different medications may affect symptoms differently."