Attention deficit hyperactivity disorder can be diagnosed earlier than previously possible, a pediatricians group says as it updated its guidelines.

ADHD is a problem with inattentiveness, over-activity, impulsivity or a combination. It is the most common neurobehavioral disorder in children, with about 8 percent of children and youth being diagnosed with it.

Children can be diagnosed between the ages of 4 and 18 years of age, compared to the previous guidelines which covered children ages 6 to 12, according to the American Academy of Pediatrics.

"Treating children at a young age is important, because when we can identify them earlier and provide appropriate treatment, we can increase their chances of succeeding in school," said Dr. Mark Wolraich, lead author of the report, in a released statement.

"Because of greater awareness about ADHD and better ways of diagnosing and treating this disorder, more children are being helped."

The new guidelines describe special considerations involved in diagnosing and treating preschool children and adolescents. They also include interventions for helping children with hyperactive/impulse behaviors who don’t meet the full diagnostic criteria for ADHD.

Treatment for preschool children should first include behavioral interventions in groups or with behavior management techniques for parents.

“Methylphenidate may be considered for preschool children with moderate to severe symptoms who do not see significant improvement after behavior therapy, starting with a lower dose,” the AAP says.

“For elementary school children and adolescents, the AAP recommends both FDA-approved medications and behavior therapy.”