"If it happens during REM sleep [the stage characterized by rapid eye movements], it could be associated with dreaming," said Dr. Mark Dyken, professor of neurology at the University of Iowa College of Medicine.
Sleep talking can be caused by stress, certain medications and certain mental illnesses. Experts estimate about half of all children between the ages of 3 and 10 talk in their sleep, and about 5 percent of adults do it.
If talk becomes violent, that's a characteristic of a more serious disorder known as REM behavior disorder.
"There will be screaming, yelling, punching and other outbusts, such as flying out of bed or lunging at something," said Walsleben.
REM behavior disorder is most common among older men. It's caused by a deterioration in the brain, Walsleben said.
There are often stories of people who wake up with crumbs in their bed but have no idea how they got there, or people who walk into their kitchen in the morning and find it inexplicably in complete disarray. People may also find that they've eaten bizarre things, like cigarette butts or flour.
Sleep experts believe there are a number of factors that contribute to sleep eating.
"If you go to bed hungry, your stomach is going to win," said Emsellem.
Certain medications can also precipitate sleep eating.
"Ambien is known to increase the risk of nocturnal eating," said Emsellem. She also said selective serotonin reuptake inhibitors -- antidepressants similar to Prozac -- can also lead to sleep eating episodes.
Stress can also play a role, especially if someone is dieting and focused heavily on food during waking hours.
Dyken also suggested the roots of sleep eating are planted during infancy and childhood.
"Parents sometimes feed kids late at night, and they wake up becasue their rhythms are off and have adpated to being hungry at night. It's induced by parents who have been negatively conditioned by a hungry child," said Dyken. "This has developed into a patient wandering around and going to the kitchen."
Sleep deprivation and improper use of sleep medication are two causes experts believe contribute to the phenomenon of texting while asleep.
Studies have shown that tech-crazed kids frequently lose a lot of sleep over those gadgets they can't put down, but that could cause them to send messages they can't even remember.
"Some of these kids are working on fumes. They just have to text and it interferes with getting into sleep. They may actually be in an early stage of sleep when they're texting," said Dyken.
Adults who take sleep medication incorrectly may also find themselves sending text messages or e-mails while asleep.
"People need to be in a dark room and in bed when they take sleep medication," said Walsleben. "A lot of times, they'll just take it and think they have 20 minutes or so to send an e-mail or a text message."
Sex during sleep, or sexomnia, is a sub-category of the parasomnias known as confusion arousals, according to Dyken. Confusion arousals occur when a person is in a mixed state of being both asleep and awake.
A recent study in the Journal of Sleep Research analyzed more than 800 people suspected of having sleep disorders. The study found that about 8 percent of them were having sex while they slept.
"There's probably a lot more of it going on than people like to talk about," said Emsellem.