FRIDAY, Feb. 28, 2014 (HealthDay News) -- Many young kids will have an occasional bad dream, but frequent nightmares or episodes of night terrors over a long period of time could be an early warning sign of mental illness, according to a new study.
British researchers found children who experience persistent nightmares may be at greater risk for psychotic experiences, such as hallucinations, interrupted thoughts or delusions, by the time they are teenagers.
"We certainly don't want to worry parents with this news; three in every four children experience nightmares at this young age," Dieter Wolke, from the University of Warwick in England, said in a university news release. "However, nightmares over a prolonged period or bouts of night terrors that persist into adolescence can be an early indicator of something more significant in later life."
Nightmares occur during the REM, or rapid eye movement, phase of sleep. People who experience a nightmare will be aware of the feeling of waking up abruptly with a sense of fear and worry.
In contrast, night terrors occur during deep sleep. These episodes usually cause a child to wake up in a panic, screaming. In some cases, people may thrash their limbs. However, children with night terrors typically don't recall their activity during the night.
In conducting the study, published Feb. 28 in the journal Sleep, the researchers analyzed a group of children six times between the ages of 2 and 9. The researchers found that children who had frequent nightmares before age 12 were three and a half times more likely to have psychotic experiences early in their teen years. Experiencing night terrors doubled the risk of these problems.
For younger children between 2 and 9 years old who had frequent nightmares, the researchers noted the risk of developing psychotic traits was one and a half times higher.
The odds they would experience psychotic experiences as teens increased with the incidence of nightmares. Those who reported one period of persistent nightmares had a 16 percent higher risk. But those who had three or more ongoing periods of nightmares throughout the course of the study had a 56 percent increase in risk, the study authors said.
"This is a very important study because anything that we can do to promote early identification of signs of mental illness is vital to help the thousands of children that suffer," Lucie Russell, director of campaigns at YoungMinds, a British charity devoted to children's mental health, said in the news release.
"Early intervention is crucial to help avoid children suffering entrenched mental illness when they reach adulthood," she added.
The research didn't prove that nightmares in childhood mean all children will develop emotional problems as teens. It only uncovered an association.
The American Academy of Family Physicians provides more information on nightmares and night terrors in children.