More than 60 percent of children with a mother and father who both sleepwalk will develop the condition as well, according to a new study published in the journal JAMA Pediatrics.

Sleepwalking is a common childhood sleep disorder that usually resolves itself by the teen years, although it can continue or appear in adulthood. Sleep terrors are another sleep disorder common in childhood and is characterized by fear, screaming, and a prolonged period of inconsolability.

The two disorders, known as parasomnias, share many of the same traits and usually occur during slow-wave sleep, according to background information in the study.

“These findings point to a strong genetic influence on sleepwalking and, to a lesser degree, sleep terrors. This effect may occur through polymorphisms in the genes involved in slow-wave sleep generation or sleep depth.

“Parents who have been sleepwalkers in the past, particularly in cases where both parents have been sleepwalkers, can expect their children to sleepwalk and thus should prepare adequately,” writes Jacques Montplaisir, M.D., Ph.D., of the Hopital du Sacre-Coeur de Montreal, and co-authors.

For the study, the researchers looked at sleep data from a group of 1,940 children. Sleep terrors and sleepwalking, including parental sleepwalking, were assessed through questionnaires.

The researchers looked for the following: the prevalence of sleepwalking and sleep terrors during childhood; any link between early sleep terrors and sleepwalking later in childhood; and the degree of association between parental history of sleepwalking and the presence of sleepwalking and sleep terrors in children.

The findings showed an overall childhood prevalence of sleep terrors (ages one and a half to 13 years) of 56.2 percent. There was a high prevalence of sleep terrors (34.4 percent) at one and a half years of age but that prevalence decreased to 5.3 percent at age 13.

The overall childhood prevalence of sleepwalking (ages two and a half to 13 years) was 29.1 percent. Sleepwalking was fairly rare during the preschool years but the prevalence increased steadily to 13.4 percent by age 10 years.

Children who had sleep terrors during early childhood (one and a half to three and a half years) were more likely to develop sleepwalking later in childhood at age five years or older than children who did not experience sleep terrors in early childhood (34.4 percent vs. 21.7 percent).

Children’s odds of sleepwalking rose along with the sleepwalking history of their parents. Children who had one sleepwalking parent had three times the odds of becoming a sleepwalker compared with those without sleepwalking parents; and children whose parents both had a history of sleepwalking had seven times the odds of becoming a sleepwalker.

Overall the prevalence of sleepwalking was as follows: 22.5 percent of children without a parental history of sleepwalking developed sleepwalking; 47.4 percent of children with one parent who was a sleepwalker developed sleepwalking; and 61.5 percent of children developed sleepwalking when both parents were sleepwalkers.

Source: JAMA