MONDAY, Feb. 11, 2019 (HealthDay News) -- Young children with autism are more than twice as likely to have sleep problems than typical kids or those with other developmental delays, a new study reports.

Several factors profoundly affect the sleep of 2- to 5-year-olds with autism spectrum disorder (ASD), said lead researcher Dr. Ann Reynolds. They are more likely to resist their bedtime, have trouble getting to sleep, suffer from anxiety regarding sleep, wake up in the middle of the night, and experience night terrors.

"It was very clear that kids with features of autism have more sleep issues," said Reynolds, an associate professor of developmental pediatrics at the University of Colorado School of Medicine in Aurora. "For almost all categories, there was a difference between ASD kids and the general population."

It was already known that kids with autism struggle with sleep. Studies have consistently found that more than half of them and possibly as many as 4 in 5 have at least one chronic sleep problem, according to Autism Speaks.

Reynolds and her team decided to delve deeper into the issue, to see which sleep problems appeared to be more affected by the symptoms of autism. They also wanted to compare kids with ASD to average children and to those who have other disorders that cause developmental delay.

Researchers recruited almost 2,000 children between the ages of 2 and 5 across the United States. They included 522 kids diagnosed with ASD; 228 with developmental delay that included aspects of autism; 534 with developmental delay unrelated to autism; and 703 typical children.

Parents completed a sleep habits questionnaire for all the children. Researchers tallied up the scores, and then compared how well the four groups fared at bedtime.

They found that kids with ASD were more than twice as likely to have serious problems getting quality sleep as kids without autism symptoms.

Kids with autism were also 45 percent more likely to have moderate sleep problems than children with other forms of developmental delay, and 75 percent more likely than typical kids.