London, Sep 12 (IANS): Children who are bullied at ages 8-10 are more likely to suffer from sleep walking, night terrors or nightmares by the time they are 12-year old, says an alarming study.

“Moreover, those who were bullied and bullied others (bully/victims) were most likely at the risk of developing sleep disorders known as parasomnias,” said professor Dieter Wolke from University of Warwick.

For the study, a cohort of children from the Avon Longitudinal Study of Parents and Children (ALSPAC) were interviewed at elementary school age (8 and 10 years) about bullying experiences and then about parasomnias at secondary school age (12-13 years).

“Being a female, having persistent sleep problems and emotional and behaviour problems in childhood additionally increased the risk for parasomnias at age 12,” Wolke noted.

Stress could be an important mechanism for the association between being bullied and parasomnias.

“Nightmares may occur when anxiety exceeds a threshold level and several studies have suggested that trait anxiety may be related to the frequency of parasomnias,” said Suzet Tanya Lereya from department of psychology.

However, even after controlling for pre-existing anxiety problems, our results showed that being bullied may increase the risk for parasomnias, she stated.

The study was published in the journal Pediatrics.