Talking

It can be hilarious to listen to the ramblings of a sleep-talker – or it can be downright freaky. Either way, about half of kids and 5 percent of adults experience somniloquy – that midnight chitchat that's harmless but could cause sleep deprivation in a disturbed partner.

Causes include certain medications, fever, stress, and mental health disorders, including substance abuse. Sleep talkers – and those who have to listen to them – may find relief by pushing back the times when they take in caffeine, certain medicines and exercise.

If the discussion is disturbing to other household members or is fearful or loud in nature, then a doctor visit may be warranted, but sleep talking is usually harmless.

Night Terrors

Who wouldn't be freaked out if woken by bloodcurdling screams and thrashing? That is exactly to what those who experience night terrors may subject family members or roommates. During night terrors, sufferers may sit straight up in bed and shout out or scream, sometimes thrashing or jerking extremities. It may be difficult to rouse the sufferer.

Night terrors usually occur in deep, non-REM sleep within two to three hours of falling asleep as the body transitions to lighter REM sleep, during which dreaming occurs. So night terrors aren't necessarily a result of having a nightmare, and sufferers don’t remember the occurrence in the morning as they would a dream.