Doctors and parents are being reminded to investigate possible sleep problems for children who have behavioural difficulties.
In not-so-good news for parents, an Australian first-of-its-kind study has shown children who experience sleep problems will also have behavioural issues, and a child that acts out is more likely to experience poor sleep.
Sleep pediatrician at Sydney Children's Hospital Dr Arthur Teng says young children can sleep up to 12 hours a day but many doctors and caregivers focus only on what happens during the eight hours they're awake.
"It really is very important message, doctors must not forget to ask about sleep when seeing children with a range of difficulties," Dr Teng told AAP.
Researchers at the Murdoch Children's Research Institute examined the complex two-way relationship between sleep problems and behavioural difficulties in almost 5000 preschoolers about to start school, from the Longitudinal Study of Australian Children.
Study participants were followed up five times from ages four to five and 12-13 years.
The study, published in the journal JAMA Pediatrics, found sleep problems (such as night-waking and an inability to sleep alone) and 'poor' behaviours such as hyperactivity were related to each other over time.
"Worse outcomes in one led to problems in the other, and vice versa," said senior author Dr Jon Quach.
The strongest relationship between these two outcomes was found in the preschool-to-school transition period.
Sleep problems were also associated with poorer outcomes in emotional difficulties, but there was no evidence that emotional problems led to poor sleep.
Dr Teng says the study highlights the 'chicken or the egg' scenario that researchers have grappled with for years.
In this case, is it the sleep problem or the behavioural problem which comes first?
"You can have a primary behavioural disorder and you can have very bad sleep, or you can have very bad sleep because of a primary sleep disorder and look like you have a secondary behavioural disorder like ADHD (Attention Deficit Hyperactivity Disorder)," Dr Teng told AAP.
Earlier this year, a group of international scientists proposed a new theory which says that much of ADHD may in fact be a problem associated with lack of regular circadian sleep.
Dr Teng says ADHD is a real biological problem, but emerging evidence suggests treating children's sleep issues first may improve the behavioural problems associated with ADHD.
