One aspect of the present invention relates to pharmaceutical compositions containing two or more active agents that when taken together can be used to treat, e.g., insomnia. The first component of the pharmaceutical composition is a GABA receptor modulating compound. The second component of the pharmaceutical composition is a serotonin reuptake inhibitor, a norepinephrine reuptake inhibitor, a 5-HT2A modulator, or dopamine reuptake inhibitor. In certain embodiments, the pharmaceutical composition comprises eszopiclone. In a preferred embodiment, the pharmaceutical composition comprises eszopiclone and fluoxetine. The present invention also relates to a method of treating a sleep abnormality, treating insomnia, treating depression, augmenting antidepressant therapy, eliciting a dose-sparing effect, reducing depression relapse, improving the efficacy of antidepressant therapy or improving the tolerability of antidepressant therapy, comprising co-administering to a patient in need thereof a GABA-receptor-modulating compound； and a SRI, NRI, 5-HT2A modulator or DRI.
