London: Children suffering from attention deficit disorder have greater difficulty in falling asleep, proves a new research. The findings showed that children with attention-deficit/hyperactivity disorder (ADHD) are unable to experience deep sleep, as they usually remain more distracted. The duration of their sleep was also found to be less than other children. "Our study confirms what many parents have experienced, which is that children with ADHD take longer to fall asleep at night," said led researcher Anne Virring Sorensen, PhD student at the Aarhus University in Denmark. Further, two out of three children with ADHD have one or more additional psychiatric diagnoses in addition to their attention disorder, which probably increases the risk of sleep disturbance. In addition, unlike in the evening the children with ADHD also showed a tendency to fall asleep faster during the day than the children in the control group. "This is somewhat surprising when you take into account that ADHD is associated with characteristics such as hyperactivity. But this hyperactivity could be compensatory behaviour for not being able to doze off during the day," Sorensen explained. For the study, published in the Journal of Sleep Research, the team included a total of 76 children with ADHD and an average age of 9.6 years participated in the study. The control group consisted of 25 healthy children. "The next step is, of course, to find out where this correlation lies so we can develop better treatments in the long term. Our survey is an important foundation for further studies," Sorensen stated.