Researchers have found that pre-schoolers with symptoms of attention deficit hyperactivity disorder (ADHD) are much less likely to be ready for school, compared to other children of the same age.

The study, published in the journal Pediatrics, included 93 children 45 children with ADHD and 48 without the condition. Aged between 4-5 years, nearly all had attended or were currently enrolled in preschool and some were enrolled in kindergarten.

It was found that 79 per cent of the children with ADHD had impaired school readiness compared with 13 per cent of children in the control group.

According to Irene Leo, Assistant Professor at Stanford University in the US,

"A lot of these kids are not identified until they're really having a lot of trouble in the school setting," Loe said.

For the study, researchers conducted tests and administered parent questionnaires to measure five areas of the children's functioning: physical well-being and motor development; social and emotional development; approaches to learning; language development; and cognition and general knowledge.

But children with ADHD were much more likely than their peers to struggle in all the four other areas measured.

They were 73 times more likely than children without ADHD to be impaired in approaches to learning; more than seven times as likely to have impaired social and emotional development; six times as likely to have impaired language development; and three times as likely to have impaired physical well-being and motor development.

The findings suggest that identifying and helping kids with significant levels of ADHD symptoms could reduce their struggles in elementary school.