All parents know the pain of trying to get their children to sleep. You can rock them. You can sing to them. You can read them "Go the F--k to Sleep" while doing your best Samuel L. Jackson impression. Fighting bedtime can be just "kids being kids," but sometimes, the problem is more serious.

A new study published in the Journal of Developmental and Behavioral Pediatrics indicates a bidirectional relationship between childhood insomnia and psychiatric problems later in life. Children with insomnia have a greater risk of developing psychiatric symptoms and vice versa.

Researchers from the Norwegian Institute of Science and Technology interviewed parents of about 1,000 4-year-olds in Trondheim, Norway using the Preschool Age Psychiatric Assessment. Two years later, 795 parents completed a follow-up interview.

"Previous studies of sleep problems in children have mainly used a questionnaire format, with questions like, 'Does your child have trouble sleeping?' But what parents define as sleep problems will vary," said Silje Steinsbekk, an associate professor and psychologist at the Norwegian University of Science and Technology, according to Psych Congress Network. "In the diagnostic interview we ask parents questions until we are confident that we have enough information to assess whether a symptom is present or not. The information we've collected is more reliable than information obtained from the questionnaire."

Children who suffered from insomnia were at a greater risk of developing conduct disorder, major depressive disorder and social phobia. Researchers found that 43 percent of children with insomnia at age four still had the symptoms at the two-year follow-up.

Also, children who exhibited signs of ADHD, oppositional defiant disorder and major depressive disorder at age four were more likely to have insomnia at age six. Sleepwalking was associated with later separation anxiety disorder.

"It is common for children to have periods when they sleep poorly, but for some children, the problems are so extensive that they constitute a sleep disorder," Steinsbekk said, according to Nordic Life Science News. "Our research shows that it is important to identify children with sleep disorders, so that remedial measures can be taken. Sleeping badly or too little affects a child's day-to-day functioning, but we are seeing that there are also long-term repercussions."