Many children with autism have difficulty sleeping and new research suggests that such nighttime troubles may be directly tied to behavioral issues.

Kids on the spectrum who didn’t sleep well at night displayed more aggression, irritability and had greater difficulty paying attention during the day, according to findings published online recently in the Journal of Autism and Developmental Disorders.

For the study, researchers surveyed parents of 81 children with autism ages 3 to 19 about their kids’ level of bedtime resistance, daytime sleepiness, nighttime wakings, sleep anxiety and duration, among other issues. Parents also answered questionnaires about behaviors including physical aggression, hostility, hyperactivity and impulsivity in their children.

Kids who woke repeatedly during the night had the most trouble with behavior, exhibiting higher levels of physical aggression, hostility, lack of attention and hyperactivity, the study found. Other issues including how long a child slept and the sleeping disorder parasomnia were also associated with increased behavior problems.

Though it’s unclear what’s driving sleep challenges in those with autism, the researchers said their findings highlight the importance of considering sleep habits, especially when evaluating behavior.

“If parents are noticing that their children are having behavioral problems, it may be helpful to make sure they are sleeping well at night,” said Micah Mazurek, an assistant professor of health psychology at the University of Missouri and an author of the study. “For all children with ASD, it is important that parents and professionals routinely screen for sleep problems. Addressing these issues will help children be at their best during the day.”