Most sleeping aids belong to the class of drugs called sedative-hypnotics, which are used to induce sleep in patients with insomnia or sleeplessness. Sedative hypnotics include benzodiazepines, such as Etizolam and Zopiclone. They are also used for the treatment of anxiety. One must use sleep medications under the supervision of a doctor. Although the exact mechanism of sleeping aids is unknown, they are presumed to work on the central nervous system to produce calming effects, inducing sleep.