It is probably no coincidence that forums for ADHD, like this one, usually have some parents who come to the site who have a child with autism. Likewise there are many newsgroups and forums for autism where some members have a child diagnosed with ADHD. Why is this so? Because there is a great overlap of symptoms between ADHD and an autism spectrum disorder. In fact I know that for some of you, your child may have been diagnosed with both disorders at one point or another.
The Interactive Autism Network (IAN) found that over a quarter of the children in IAN Research with an Autism Spectrum Disorder had also been diagnosed, at some point in their lives, with ADHD. When they took a look at children having an autism spectrum disorder who were 10-years of age and older, the percentage of these children who had previously been diagnosed with ADHD shot to 52%. This tells me that sometimes it takes awhile to figure out that a child’s symptoms may mean something more than ADHD alone.
Is it possible to have autism and ADHD?
Some experts say no, that these are two separate disorders and that being diagnosed with one disorder will automatically exclude the other diagnosis. Part of the diagnostic criteria for ADHD states that the symptoms do not happen only during the course of a Pervasive Developmental Disorder which includes Asperger’s Disorder and autism. Yet there are other experts, teachers, and parents who feel that one person can have both disorders. Diane M. Kennedy is one parent who delves into the similarities between these two conditions in her book, The ADHD-Autism Connection. Kennedy has three children who were diagnosed with ADHD. But something seemed different with her youngest son who did not respond favorably to traditional ADHD treatment. It took nearly seven years for her son to eventually be diagnosed with Asperger’s Disorder. She is not the only parent to go through this diagnostic journey and it leaves the question as to whether or not autism is sometimes being misdiagnosed as ADHD or whether these two disorders are simply co-morbid conditions.
Some are advocating that ADHD and autism be co-diagnoses in the next version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V), which is supposed to come out in May 2013. To add to the confusion, the diagnosis of Asperger’s Syndrome may be eliminated in this new edition.
What are the similarities between ADHD and autism?
• Inattention
Children who have ADHD and children with autism may have difficulties with paying attention. Yet despite the inability to filter out extraneous stimuli in order in order to concentrate on some things, children who have either ADHD or autism may also have what is known as hyperfocus, which is an intense focus upon select topics or interests.
• Hyperactivity
Some children with ADHD or autism may engage in hyperactive behavior. This means that the child may be fidgety, restless, constantly on the go, or talking excessively.

