Drugs such as ritalin can be used to treat ADHD
Injuries in very young children are associated with later diagnosis of attention deficit hyperactivity disorder, UK research suggests.
A study of 62,000 children shows both head and burn injuries before the age of two are linked with almost double the risk of ADHD diagnosis by age 10.
It suggests injuries in general are an early sign of ADHD behaviour.
The British Medical Journal study may help GPs spot children who need specialist referral, experts said.
Previous research has suggested mild brain injury is associated with behavioural changes in children.
The researchers said that although a link between head injury and ADHD had been shown it was not clear which comes first.
In the latest study, a team of UK and US researchers, predicted that they would find higher rates of ADHD diagnosis in children who had been treated for a head injury when they were younger than in those who had burn injuries.
Using data from more than 300 general practices from between 1988 to 2003 they found that both types of injuries were associated with greater rates of ADHD diagnosis than children who had no injuries.
The study also found that children who had a head injury after the age of two had a greater likelihood of being diagnosed with ADHD before their 10th birthday among all three groups.
Children who go on to develop ADHD may exhibit more risk-taking behaviours as young children and are therefore more likely to experience early injuries, the researchers suggest.
There is considerable debate over the cause of ADHD.
The National Institute for Health and Clinical Excellence guidelines state that risk factors for ADHD are likely to interact and that although genetics is important, environmental factors such as injury or maternal smoking may also contribute.
Study leader Professor Heather Keenan, from the University of Utah, said: "The head injury itself does not seem to be causal in the development of ADHD.
"Rather, some other factor seems be associated generally with early injury and the development of ADHD."
In an accompanying editorial, Dr Morris Zwi, a consultant in child and adolescent mental health in south west London said the research suggests the main symptoms of ADHD - excessive attention, hyperactivity, and impulsivity - might predispose children to injury.
"The findings indicate that primary care clinicians should assess children with injuries for symptoms of ADHD and continue to monitor them," he added.
Professor Steve Field, chair of the Royal College of GPs, said diagnosing ADHD was "very difficult".
"This paper is useful because it highlights that children who present with accidents could well have ADHD and might benefit from specialist referral."