As a clinical psychologist, I am often faced with a dilemma when diagnosing children who display clusters of symptoms characteristic of both autism and attention-deficit hyperactivity disorder. Do these children suffer from two separate conditions, or can we view the ADHD symptoms as a byproduct of a more pervasive diagnosis of autism? Young children with autism have triple the rate of ADHD symptoms compared to normally developing children. In one study, researchers asked the parents of four-to-eight-year-old children with autism if they had symptoms of ADHD (e.g. if the children were able to wait their turn, if they interrupted others when they were speaking, if they could slow down when they needed to, etc.). Of the children with autism, 29% showed signs of comorbid ADHD, all of whom were boys. These symptoms of hyperactivity and inattention can complicate treatment of autism, but the fact that autism and ADHD go hand-in-hand for some children is not surprising. According to Dr. Andrew Adesman, chief of pediatrics at Schneider Children's Hospital ,“Something that’s going to affect the brain and cause one developmental outcome may also cause a second developmental outcome.”
In another study, researchers compared
children with high-functioning autism (accompanied or not by ADHD) with non-autistic
children who had ADHD. They looked at different types of memory, learning, and
behavior. They found that there were remarkable similarities between the
children with high-functioning autism and those with ADHD. They had similar levels
of working memory and memory in general. The two groups had similar problems in
all three areas that were measured. This was surprising: The researchers
expected the children with autism to be more impaired when it came to
remembering tasks after a delay, and the children with ADHD to be more impaired
in actually acquiring new knowledge. Additionally, they were able to contradict
some previous studies that found that only complicated tasks illustrated the
working memory issues in high-functioning autistic children. In fact, no
significant differences between the children with autism, those with ADHD, and neurotypical
children were found when it came to visual working memory. Of course, the power
of the findings of this study may be weakened by the fact that the group of
autistic children was divided into two subgroups – those with symptoms
consistent with ADHD and those without, and also because the groups were not
equally weighted by gender. ADHD symptoms, as in typically developing children,
tend to affect boys with autism more than girls. The researchers did not
subdivide the group of typically developing children in a similar fashion
because that group all had similar levels of attention deficits. In dividing up
the autistic group, it was possible to look at the way autism interacts with
ADHD, because some of the children had both sets of symptoms, and some only had
one or the other. The group of children with high-functioning autism and ADHD
symptoms had more serious issues in their verbal working memories than either
of the other two groups, including the ADHD group. The researchers found this
to be interesting, because it hints at an additive effect when it comes to
attention problems and autism; Those with both sets of symptoms are more
impaired than those with either one alone. This is not the first time that an
additive effect has been found for autism and attention issues, however, as a
similar effect has been found with deficits in inhibition. Another finding of
the study is that attention deficits alone could not explain the difficulty which
children with autism had in the acquisition of new
information. That difficulty appears to be characteristic of autism, regardless
of the child’s ability or inability to regulate their attention.
These findings necessitate the
development of questionnaires and treatments specifically to measure ADHD symptoms in children
with autism and then help them, because their problems and symptoms may differ
from those of children who have ADHD alone. Additionally, they bring attention
to the fact that those with autism and attention problems at a clinical level
may have further difficulties with their verbal working memory and with their
ability to recall information in general. This may help the parents of autistic
children better understand the issues they are facing and provide more directed
and relevant help. It also explains some of the other findings on children with
high-functioning autism and attention, because it appears that this is a
heterogeneous group, and there would be two findings for each of the two
groups; combined results may be misleading. Future research should work on
developing more specific questionnaires and tests to measure this pattern, and
explore whether children with high-functioning autism can benefit from working
memory training and how the symptoms of ADHD may complicate the efficacy of
other special instruction the children are receiving, such as social skills
training.
Author Bio: Dr.
Tali Shenfield is a Clinical Psychologist and Director of Richmond Hill
Psychology Center. She holds a PhD in Psychology from the University of Toronto
and is a member of the College of Psychologists of Ontario, Canadian Register
of Health Service Providers in Psychology, and Canadian Psychological
Association. When she is not busy with psychological assessments and
psychotherapy, Dr. Shenfield spends time on writing professional articles on parenting
and psychology topics. You can follow her on Twitter at @DrShenfield.
Image Credit: http://www.flickr.com/photos/ebolasmallpox/2945610839
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