Almost 30% of young children with autism also show signs of
attention-deficit/hyperactivity disorder (ADHD), a rate that's three times
higher than it is in the general population, a new study shows.
"We don't know the cause for ADHD in most cases. We don't know the cause of
autism in most cases. It's not surprising that something that's going to affect
the brain and cause one developmental outcome may also cause a second
developmental outcome," said Dr Andrew Adesman, chief of developmental and
behavioural paediatrics at Steven and Alexandra Cohen Children's Medical Center
in Lake Success, NY. He was not involved in the study.
Kids in the study who had both problems together also tended to have more
difficulty learning and socialising than children who had autism alone.
ADHD treatment and autism
The researchers noted that the treatment of ADHD may benefit children with
autism if they aren't making progress with autism treatment programmes, which
often require sustained focus on specific skills.
"In a child [with autism] who has great difficulties with attention, or
hyperactivity or both, you really have to layer in another level of intervention
strategies for them," said study author Rebecca Landa, director of the Center
for Autism and Related Disorders at the Kennedy Krieger Institute in
For the study, which is published in the June 5 online issue of the journal
Autism, researchers asked parents of kids enrolled in a community-based
study of child development about symptoms of attention and hyperactivity -
whether or not children could wait their turn, interrupted others who were
speaking, fiddled with things during meals or could not slow down, for example.
All the children in the study were between the ages of four and eight.
Out of 62 children diagnosed with autism, 18 (29%) also showed signs of
ADHD. A previous study of slightly older children found that 31% of children had
the two disorders together.
"It's not surprising," said Dr Patty Manning-Courtney, director of the Kelly
O'Leary Center for Autism Spectrum Disorders at Cincinnati Children's Hospital
"What's good about this study is that they went to the trouble to look at who
met diagnostic criteria and what was different about those children," said
Manning-Courtney, who was not involved in the research.
All the children who had both problems together were boys. Boys have higher
rates of autism and ADHD than girls, research shows.
Hard to tell
One limitation of the study was that researchers had to rely on
questionnaires that are meant to spot ADHD in typical children. There really
aren't good tests for attention and hyperactivity developed for kids with
autism, and their problems may look different than those seen in typical
Children who are higher functioning on the autism spectrum can have fairly
obvious problems with attention.
"It's not that they have a deficit of attention. It's that they can't
allocate their attention, or shift their attention to what it needs to be on,"
Courtney-Manning said. "I talk to parents of kids with autism about attention
regulation more than attention deficit."
In children who are more severely autistic, ADHD can be harder to spot.
"It's hard to tell if their activity level is different because they're
delayed or they're more severely autistic or if it's ADHD," Courtney-Manning
But if parents and teachers are noticing that attention or activity problems
are interfering with a child's ability to make progress, that's the time to seek
help, she noted.
First-line treatments for attention problems in kids with autism involve
behavioural interventions that aim to teach kids to better control their
If the behaviours don't get better with help, Landa said doctors will then
move on to medication.
"If your child is having those kinds of problems, it's worth mentioning to
the child's doctors and also touching base with the child's teachers," Landa
For more information on ADHD, head to the US Centers for Disease Control