How to differentiate an ADHD and an ASD diagnosis: Expert clinician webinar

Overlapping symptoms

Jess and Ryan emphasize the significant overlap in symptoms between ADHD and ASD. It is specifically visible in areas like attention, social communication, and sensory needs. This overlap often leads to misdiagnosis or delayed diagnosis, especially in younger children.  

Jess said: “I’ve seen many adults come through my clinic where they're thinking about co-occurring needs or have had a referral for possible ADHD. And actually, we're seeing other elements of neurodivergence instead."

"Whether it's ADHD or an autism spectrum condition, we see that camouflaging or masking behaviors."

“Sometimes, based on feedback, people become quite aware of these social communication differences, which I imagine is different for young people.” 

She explains that there may be a child who's very hyperactive, and when they’re observed in a clinic, there’re higher sensory needs. ADHD also comes with its own sensory needs, but in autism, we often see these restricted and repetitive movements. For example: rocking, hand clapping, and some stimming and regulatory behaviors.  

Ryan added: “Individuals are labelled as hyperactive because they're hand flapping or because they're rocking. It goes back to context. When are these behaviors occurring? Is this a stressful environment? Is it always present? Is it only present when we're doing specific tasks?” 

Core differences in symptomatology

Jess and Ryan highlight the core differences between ADHD and ASD, particularly in social communication, sensory regulation, and language use. 

Ryan noted that the crux of ASD diagnosis really falls on social communication. This is the inability to pick up on nonverbal cues and social reciprocity. For example, a child with ASD might fixate on a specific topic and struggle to engage in reciprocal conversation when someone engages with the topic.  

In contrast, a child with ADHD may bounce between topics, struggle with sustained attention, and exhibit impulsivity in conversation. 

Jess summarized that in ADHD, hyperactivity and impulsivity often manifest as a need to 'get energy out.' Whereas, in ASD, sensory-seeking behaviors like rocking or hand-flapping are more about self-regulation and managing overwhelm. 

Ryan said, "I've seen people with ASD persevere and hammer through tasks because they become hyperfixated. That's not always a good thing, but they're able to tap into that, whereas people with ADHD tend to see burnout, especially in pediatrics. 

“They've hit that wall where the child with ASD may persevere. So, it's a little bit different that way in terms of looking at that differentiation. It's when and where the symptoms are present.” 

Developmental and age-related considerations

The discussion underscores the importance of considering developmental stages, particularly the age range of 3 to 7. This is when social communication skills are developing. 

Ryan commented, "That time frame when children are starting to learn all of these different types of social communications and understanding other people's emotions and how to reciprocate."

“Individuals with ASD, we start seeing some weaknesses where they're not doing some of those things. So that's a that's a very pivotal age that we're looking at which was a big part of the clinic that I worked with as well.” 

Jess compared this to adults, explaining what we often see as masking or camouflaging behaviors. Individuals have learned to compensate for social communication difficulties. For example, they might force eye contact or rehearse conversations to fit societal expectations." 

Trauma and comorbidities

Both the ADHD and ASD populations are at higher risk for trauma. This is due to difficulties with social communication, impulsivity, and vulnerability to exploitation. 

Jess discusses her work with adolescents and adults and how impulsivity in ADHD can lead to risky behaviors. Social communication difficulties in ASD can make individuals more vulnerable to exploitation or misunderstanding in relationships. 

She said, “Those who are neurodivergent may be more susceptible to things like domestic abuse. We can get patterns of trauma embedded, whereas the break in routine or the change of environment may feel too much to exit.”  

Trauma can have long-lasting effects, especially when individuals with ASD or ADHD are misunderstood or mishandled in traumatic situations. Clinicians must be aware of these risks and provide appropriate support.