Sleep is a state of rest when the eyes are closed (for most species) and consciousness is altered. Dreaming takes place once a lifeform reaches REM sleep.
Unable to reach REM sleep within Tyken's Rift, the crew of the USS Brattain went insane and seemingly murdered each other. (TNG: "Night Terrors")
Because he was an android, Data did not require sleep, a fact that disturbed Captain Picard when he was trying to fall asleep on a Klingon vessel headed for the Romulan Star Empire on a secret mission in 2368. (TNG: "Unification I")
Species 8472 do not sleep. (VOY: "In the Flesh")
Sleep technologies
See also
- Dream species
- Hibernation