Objective: This is the first trial examining duloxetine for generalized social anxiety disorder (GSAD) and the effect of increased dose for those without early remission.
Methods: Individuals (n=39) with GSAD received 6 weeks of open-label duloxetine 60 mg/day; those with a Liebowitz Social Anxiety Disorder Scale (LSAS) score >30 at week 6 were randomized in double-blind fashion to an additional 18 weeks of continued duloxetine 60 mg/day or to duloxetine 120 mg/day.
Results: Duloxetine was associated with a significant LSAS reduction at week 6 (91.3 [17.7] to 69.8 [28.5], paired t [df]=5.2 [38], P<.0001), and randomized participants overall continued to improve at week 24 (74.6 [23.9] to 60.3 [29.7]; paired t [df]=3.3 [27], P=.0026). Though the increased dose strategy was associated with a moderate effect size (Cohen's d=.57), there was no significant difference at week 24 endpoint in LSAS reduction (20.5 [26.0] versus 7.3 [17.2], t [df]=1.6 [26], P=.13) nor remission (33% versus 8%) for duloxetine with dose increased to 120 mg/day compared to duloxetine continued at 60 mg/day. Overall, 44% (17/39) discontinued prior to week 24.
Conclusions: Though with limited power, these data provide preliminary support for the efficacy of duloxetine for GSAD, and suggest continued improvement but limited remission overall at 24 weeks for individuals remaining symptomatic at week 6. These observations warrant further controlled study.