Sleep difficulties are very common among toddlers and preschool-aged children who are receiving clinical treatment for a wide range of psychiatric disorders, according to a recent study.

John Boekamp, who led the study, and his colleagues were interested in learning more about sleep and sleep problems in young children with behavior problems, as early sleep problems may be both a cause and consequence of children's difficulties with behavioral and emotional self-regulation.

"The most common sleep difficulties reported nationally for toddlers and preschoolers are problems of going to bed, falling asleep and frequent night awakenings - collectively, these problems are referred to as behavioral insomnias of childhood," Boekamp, clinical director of the Pediatric Partial Hospital Program (PPHP) at Bradley Hospital, said in a statement.

For the study, the research team examined the nature and prevalence of diagnostically defined sleep disorders, including Sleep Onset Insomnia (SOI) and Night Waking Insomnia (NWI), in a group of 183 young children admitted to the program.

Diagnosable sleep disorders, particularly SOI, were quite common in the group, exceeding previous estimates obtained in community settings. Overall, 41 percent of children in the study also met diagnostic criteria for a sleep disorder. Sleep problems were especially common in children with disruptive behavior, attention, anxiety and mood problems.

"It is important for families to be aware of how important sleep is to the behavioral adjustment and wellbeing of young children," Boekamp said. "Sleep disorders may be unrecognized and under-diagnosed in young children, particularly when other behavioral or emotional problems are present."

Difficulties with sleep may be particularly important to address when children are also struggling with challenging daytime behaviors, such as problems with compliance, aggression, attention and mood. Sleepiness and fatigue may exacerbate these problem behaviors.

This study is a "great reminder" that it's critical for mental health providers working with young children and their families to ask about children's sleep.

"Simple questions about children's sleep patterns, including how long it takes a child to fall asleep at night and how frequently a child awakens after falling asleep, may yield important information that is relevant to clinical care, even when sleep problems are not the primary focus of treatment," Boekamp said.

The findings were published in the journal Child Psychiatry & Human Development.