A James Cook University study has found sleep problems in pre-schoolers could help predict whether children are at risk of developing conditions such as autism spectrum disorder and ADHD.
Sixth-year medical student Emily Sawyer's honours research project investigated whether disruptive sleep patterns in pre-schoolers could be used to predict children at risk of developing a range of emotional and behavioural disorders.
"Very few studies have examined sleep problems in pre-schoolers," she said. "This is surprising, given that pre-school age, when children are typically four to six years old, is a major period of sleep consolidation, a time when children begin to develop adult-like sleeping patterns.
"Sleep problems in this age group are more likely to persist than those from infancy and importantly, strongly predict problems in later childhood and even into adulthood.
"Insufficient sleep has been associated with poorer learning, heightened emotional reactivity and poor mental health. Sleep problems have been found in many major forms of child emotional and behavioural disorders, including anxiety, depression and ADHD."
Ms Sawyer reviewed past research and also analysed data on 758 children who took part in an Australian longitudinal study, Effective Early Education Experiences (E4Kids) from 2010 to 2015.
She looked at data collected when the children were aged four to six, then again two years later.
While most previous studies have looked at sleep problems in isolation, she explored connections between individual sleep issues and their association with the health of children two years later.
She identified three persistent sleep problems – short night sleeps, night awakenings and nightmares – which were strongly associated with specific emotional and behavioural disorders.
"Short sleep was associated with autistic spectrum traits – peer problems and poor social skills," the researcher said.
"Previous studies have shown that children diagnosed with autistic spectrum traits often have very poor sleep. However, to our knowledge, no studies have examined how specific early sleep problems may be a marker of later ASD (autistic spectrum disorder)."
Ms Sawyer also found that pre-schooler nightmares were associated with emotional and peer problems.
"These are both classified as internalising disorders, which suggest conditions such as anxiety and depression. Prior studies of internalising disorders in adolescence have shown a strong association with sleep problems."
Night awakening – when children typically wake up three or more times during the night – is strongly associated with autistic spectrum traits, hyperactivity, emotional and peer problems.
Early in her research, Ms Sawyer discovered that there were no standard measures to compare children's sleeping habits. After reviewing available data on the subject, she developed specific methods to assess sleep duration, as well as abnormal rates of napping and timing of sleep.
She hopes that the results of her study will lay the foundation for future research into sleep and its association with developmental disorders in young children.
"This is important, as persistent sleep problems can be identified from as early as pre-school age, whereas emotional and behavioural disorders are not usually diagnosed until children reach school age," Ms Sawyer said.
"We hope that research like ours will assist in enabling earlier identification of problems and subsequent support for children."
Ms Sawyer's research project was supervised by Ronny Gunnarsson, Adjunct Professor in General Practice, Gothenburg University, Sweden, and Associate Professor Honey Huessler, Medical Director Child Development and Senior Medical Officer Respiratory and Sleep Medicine, Children's Health Queensland, Centre for Children's Health Research, University of Queensland.
