Major Depressive Disorder (MDD) and generalized anxiety disorder (GAD) can coexist and patients may have insomnia marked by difficulty falling and/or staying asleep and potentially reduced quality of life (QoL). Eszopiclone has been shown to improve sleep in patients with insomnia comorbid with MDD or GAD. This analysis examined the effects of eszopiclone co-therapy on the HAM-D17 in these two patient populations.

Patients with insomnia comorbid with MDD and baseline HAM-D17>14 (excluding insomnia items; n=545) received morning fluoxetine and were randomized to nightly eszopiclone 3mg or placebo for 8 weeks. Patients with insomnia comorbid with GAD and screening MADRS≤20 (n=593) received daily escitalopram oxalate and were randomized to nightly eszopiclone 3mg or placebo for 8 weeks. Clinician-administered HAM-D17 was evaluated at baseline and Weeks 4 and 8 in both studies.

Baseline HAM-D17 median scores were 22 and 15 in the MDD and GAD populations, respectively. Change from baseline HAM-D17 scores were significantly improved (p<0.02) with eszopiclone co-therapy at Weeks 4 (−10.0±7.6) and 8 (−13.6±7.7) relative to fluoxetine monotherapy (−8.4±6.8 and –11.5±7.1) in the MDD population. Similarly, change from baseline HAM-D17 scores in the GAD population were significantly improved (p<0.002) with eszopiclone co-therapy at Weeks 4 and 8 (−5.8±4.9 and –6.7±5.4) relative to escitalopram monotherapy (−4.3±5.1 and –5.4±5.6).

Treatment of insomnia with eszopiclone was associated with significant improvements in HAM-D17 scores relative to fluoxetine or escitalopram monotherapy in patients with insomnia comorbid with MDD or GAD, even after removal of insomnia items from the scale.