Is it ADHD or an Autism Spectrum Disorder?

by Anne Windermere Patient Advocate

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.

  • Impulsivity

Children with ADHD or autism may act impulsively and without recognizing the consequences of their actions. Some impulsive behaviors shared by children with ADHD or autism may include interrupting others, engaging in risky or dangerous behavior, and/or aggression.

  • Sensory Processing Difficulties

A co-morbid disorder to both autism and ADHD is what is known as sensory integration disorder. This describes a condition where the child is unable to regulate stimuli coming in through their senses. For example some children with sensory integration disorder will demand that the tags be cut out of all their clothes because of tactile issues, they may cover their ears because they perceive some sounds as painful, or they may be extremely picky eaters because they have an aversion to certain textures of food.

  • Behavior Problems

We talk a lot here about behavioral issues on ADHD Central and for good reason. Many children with an ADHD diagnosis may have behavioral challenges which set them apart from their peers. Likewise, many children with an autism spectrum disorder may have significant behavior problems which interfere with learning and making friends.

  • Impaired Social Skills

The child with either ADHD or autism may have great difficulty in making friends or fitting in at school or with their peers. This may be caused by an inability to figure out the rules of social interaction and engagement.

What are the differences between an autism spectrum disorder and ADHD?

So far we have a lot of similarities going on between a child with ADHD and a child with autism. But what are the differences which indicate that there is more than just ADHD going on?

  • Communication skills are usually more impaired with an autistic child

A child with ADHD may have some communication difficulties or trouble grasping some aspects of language especially if they have a co-morbid condition of a learning disability or speech problems. Yet overall, the child with autism is going to have more significant communication difficulties. These difficulties are not limited to expressive language. The child with autism may have great challenges in deciphering body language, facial expressions, tone of voice, sarcasm, and other elements of non-verbal communication. They may have difficulty with pragmatic language skills
or those aspects of interpersonal communication such as all the unwritten rules of how to carry on a conversation. The communication difficulties of the child with ADHD are not going to be as pervasive as with autism.

  • Children with autism or Asperger's Syndrome may lack "theory of mind." Although some children with ADHD may seem to lack empathy at times there is more cognitive awareness of how others may think or feel than with a child who has an autism spectrum disorder. Some experts theorize that one of the hallmark distinctions between autism and other disorders is a lack of theory of mind. Some define theory of mind as the ability to imagine other people's mind states including their thoughts, feelings, and intentions. We use theory of mind everyday to anticipate how others will react or feel to certain events or actions.

There is a classic assessment used to see if a child has theory mind which was developed by Uta Frith called the Sally-Ann Test. There are some people who have autism or Asperger's Syndrome who are offended by this theory and have created their own version of a diagnosis for the "neurologically typical" which I find to be amazingly on target.

  • Children with ADHD are usually more capable of engaging and connecting with others.

I may get some flak for this one but I do think that the child with ADHD may have problems with social skills but they still may be more able to engage with others than the child who has an autism disorder. And here is what I mean by this. Some of the pre-verbal communication skills essential for social interaction include eye contact, a desire to share, and joint attention.

Many children on the autism spectrum will avert their gaze to not look into someone's eyes because it makes them feel uncomfortable. But imagine all the social cues which are lost by not maintaining any eye contact.

Along with a lack of eye contac, another early sign of autism for my son was a lack of pointing. He didn't point and he didn't share. There was never an utterance of "Look at me" or a coming to show me something he did such as a drawing.

Joint attention is also critical for engaging with another person. An example of joint attention is when a toddler follows his mother's gaze to a bird on the window sill. The normally developing toddler will react by looking at the bird and then will look back to the parent and maybe smile in that shared moment. The child with autism may not pay attention to gestures, pointing, or track the eye movements of others.

In later years the child with autism or Asperger's Syndrome who develops language may perseverate on favorite idiosyncratic topics to the exclusion of the interests of others. In short, the child with an autism spectrum disorder seems to have much more difficulty with connection than the child with ADHD.

Reaction to medication may help differentiate the diagnoses

There are many other differences and similarities between the symptoms of ADHD and autism, too numerous to list. But I did want to add one other essential difference which may help to differentiate the two disorders. The way in which the child responds to medication may be telling in which diagnosis is more accurate. Typically, the child with autism is not going to respond as favorably to the ADHD medications including psychostimulants as well as the child with ADHD. These types of medications may heighten irritability and hyperactivity for some children on the autism spectrum.

However, there is a subset of children who have autism or Asperger's Syndrome who do react well to the traditional ADHD medications. In probably one of the best articles I have read on this topic, Is it Aspergers' or ADHD?, Doctor Daniel Rosenn offers his hypothesis:

Perhaps in the future we will know more about the causes for both ADHD and autism and we will be in a better position to make clear cut distinctions between these diagnoses. It is my personal theory that we will come to understand that there may be many subsets of disorders within the giant umbrellas of ADHD and autism and some of these classifications may overlap. Right now though, there is still much confusion which is hard on both the child and the parents.

If you are a parent who has a child who is limbo as far as a definitive diagnosis, please know that you are not alone. We are here to listen and provide support as well as give you information and resources to help you and your child along your journey.

We would love to hear from you. Do you suspect that despite your child's ADHD diagnosis, that your child may also have symptoms of autism? Have any of you experienced having your child receive a diagnosis of ADHD only to have it change later to an autism spectrum disorder diagnosis? Do you believe that a child can have autism and ADHD at the same time? What do you feel are the differences in ADHD vs. autism symptoms and behaviors?** Additional Resources**

Anne Windermere
Meet Our Writer
Anne Windermere

These articles were written by a longtime HealthCentral community member who shared valuable insights from her experience living with multiple chronic health conditions. She used the pen name "Merely Me."