The Latest Research on Autism plus ADHD

In our extensive clinical experience, we often recognise the signs of attention deficit hyperactivity disorder (ADHD) in autistic children and adults. A recent research study has confirmed that 48% of autistic children and adolescents are both autistic and ADHD (Kerns et al., 2021). Even if an autistic person does not meet the full diagnostic criteria for ADHD, they often have fragments of ADHD in their profile of abilities.

Being autistic and ADHD is associated with significantly poorer cognitive performance and social/adaptive abilities compared to autism without ADHD. The combination may have a distinctive pattern of abilities and neurology compared to autism without ADHD. Those who have both characteristics are also more likely to have greater impairments in executive and social processing and develop emotional/behavioural difficulties, especially externalizing problems (Rosello et al., 2022).

Hannah Gadsby (2022, page 267) describes their autism, executive functioning, and attention difficulties in her autobiography:

The bit of the brain that is responsible for prioritising, integrating and sorting out all the incoming – is just a bit sh** at its job. My brain is a Ferrari with bicycle brakes, it has no filing system or what medical professionals call ‘executive function.’

It’s not so much that I have a deficit in attention. I take it all in. I pay attention to everything. If anything, it’s attention overload. The deficit is working out what is important and dealing with it in a timely manner.

New conceptualisations of ADHD

Clinicians and researchers seek patterns of abilities and behaviour associated with ADHD and develop new conceptualisations. Two new conceptualisations of ADHD have recently been identified: Emotion Regulation Difficulties (ERD) and Sluggish Cognitive Tempo (SCT).

Emotion Regulation Difficulties

Forty to fifty percent of ADHD children have emotion regulation difficulties (ERD) characterised by anger, irritability, and low distress tolerance. (Faraone et al. 2019). There seems to be an emotional reaction without reflection, inhibiting the effectiveness of behaviour management strategies and cognitive behaviour therapy (CBT). There is also the risk of greater social rejection by peers due to episodic explosive reactions, family distress, reduced quality of life and educational and occupational outcomes. ERD may be linked to hyperactivity and impulsivity and may be a diagnostic subtype (Martel, 2009).

Sluggish Cognitive Tempo

Sometimes, a new term is associated with interesting imagery. Sluggish Cognitive Tempo (SCT) or Cognitive Disengagement Syndrome (CDS) has a distinct cognitive and motor pattern and occurs in 25-40% of ADHD teenagers and young adults (Becker et al., 2016). The characteristics include excessive daydreaming, being lost in a mental ‘fog’ underactive and slow moving. SCT is associated with social withdrawal and internalising symptoms, especially depression and is linked to inattention.

There is discussion in the research literature as to whether ERD and SCT should be considered as part of the ADHD diagnostic criteria. Both descriptions could also be applied to those individuals who have both autism and ADHD.

The neurology of autism plus ADHD

Research on the neurology of autism plus ADHD has confirmed that the combination is not simply an overlap of the associated neurological structures but a unique frontoparietal brain dynamic (Watanabe & Watanabe, 2023) with a distinct and robust neuroanatomical signature of widespread increases in cortical thickness and certain decreases in surface area (Bedford et al., 2023).

The experience of autism plus ADHD

Autism and ADHD have many distinct characteristics. When autism and ADHD combine, the characteristics of both neurotypes can create considerable confusion and internal conflict as to whether autism or ADHD is dominant in a specific situation. Examples are:

⦁ Struggling to be on time (ADHD) but upset when a few minutes late (autism)
⦁ Forgetting steps in plans (ADHD) but needing to execute plans perfectly (autism)
⦁ Enticed by novel foods (ADHD) but being particular about food taste and texture (autism)
⦁ Needing novel experiences (ADHD) and needing predictability and sameness (autism)

Noah described his contrast between both and subsequent challenges:

One of the biggest challenges I face is that my brain often works in non-linear ways. I can see connections and patterns that others miss, and I have a natural ability to think creatively and come up with unique solutions to problems. But at the same time, I also struggle with organization, executive functioning, and other challenges that can make it difficult for me to bring my ideas to fruition.

An AuDHDer, their family members and teachers often have difficulty determining the dominance of an autistic or ADHD characteristic and how a compromise or resolution can be achieved. They will need access to expertise in both neurotypes.

Autism plus ADHD and mental health

Autistic and ADHD children and adolescents are more likely to experience anxiety, depression, and other mental health conditions than those who have only one of the neurtypes (Casseus et al., 2023). There is also an association between autism, ADHD and substance abuse (Butwicka et al., 2017; Ressel et al., 2020) and suicide (Kolves et al. (2021).  

Autism plus ADHD and depression

A recent study of those who are autistic and have ADHD has found a prevalence of depression at age 19 of 23% and 44% before the age of 30 (Thapar et al., 2023). The risk factors for depression in ADHD and Autism, according to the Thapar et al. study are:

1: Genetic liability
Both ADHD and autism are highly heritable and parents of those with ADHD and Autism have heightened rates of depression.

2: Trauma
The characteristics of both conditions increase the likelihood of trauma when combined with social-environmental stressors, which increase depression risk.

3: Social-environmental mechanisms
Friendship quality, peer problems, being victimised, loneliness, and lack of social support networks can contribute to depression.

4: Academic competence
Sluggish Cognitive Tempo (SCT) can lead to low academic achievements and low self-esteem, which leads to depression.

5: Other disorders
This can include anxiety and alexithymia and the effects of emotion regulation difficulties (ERD) leading to emotion dysregulation and feelings of intense despair and suicidal ideation.

Artificial Intelligence (AI)

In the future, Artificial Intelligence (AI) tutors may help students who are autistic and ADHD to achieve greater academic success. They are often more patient than a human teacher and can incorporate data from cognitive assessments, learning profiles and personality to create an individualised curriculum. There is no waiting for teachers with real-time feedback, and AI can adjust the curriculum based on past and current performance. Another advantage is that you do not have to put your hand up in front of 30 students to ask for help.

References

Becker et al. (2016). Jr of the Am. Acad. Of Child & Adolescent Psychiatry
Bedford et al. (2023). Brain-charting autism and ADHD (In press)
Butwicka et al (2017). Journal of Autism and Developmental Disorders 47, 80-89 
Casseus, Kim, and Horton (2023). Autism Research  
Faraone et al (2019). Journal of Child Psychology and Psychiatry)
Gadsby H. (2022) Ten Steps to Nanette. Ballantine Books
Kerns et al (2020) Autism 24 515-525
Kolves et al (2021). JAMA Network Open January 2021 
Martel (2009), Journal of Child Psychology and Psychiatry
Ressel et al (2020). Autism 24, 899-918 
Rosello et al (2022). Autism 26, 743-760 
Thapar et al. (2023). The Journal of Child Psychology and Psychiatry 64:1, 4-15.
Watanabe and Watanabe (2023) eNeuro 10 (7)