By Professor Tony Attwood and Dr Michelle Garnett
In this two-part article we discuss the prevalence of ADHD in autistic children and adolescents, the effect of being autistic and having ADHD, and how to help your child.
Prevalence of ADHD in Autistic Children
Autism occurs in one in 44 children (CDC, 2021), while attention deficit hyperactivity disorder (ADHD) occurs in one in 20 children (Polanczyk et al, 2014). We have found from our extensive clinical experience that the two conditions can often occur in the same child, with research indicating that the co-occurrence rates for autism plus ADHD vary from 30% to 70%. A recent comprehensive study confirms that 48.4 % of autistic children and adolescents have both conditions (Kerns, Rast and Shattuck (2021). Research has also suggested that autistic girls have lower odds of also having ADHD (Angell et al, 2021).
The primary characteristics of the combination of autism and ADHD are autistic social communication and restrictive, repetitive behaviours and interests as described in the diagnostic criteria for autism and the ADHD characteristics of inattention and hyperactivity/impulsivity and impaired executive functioning (Krakowski et al, 2022).
Perhaps the best way to understand the concept of executive functioning is to think of a chief executive of a large company, who can perceive the ‘big picture,’ consider the potential outcomes of various decisions, is able to organize resources and knowledge, plan and prioritize, and modify decisions based on results and complete projects on time.
Being autistic and having ADHD
Being autistic and having ADHD will affect a student’s academic performance, with many students underachieving, considering their intellectual abilities. This will adversely affect their self-esteem, and is associated with poorer social, occupational, and psychological functioning as an adult (Unitt, 2022). The combination will also increase the risk of developing behaviours of concern to parents and teachers and mental health issues during childhood and adolescence (Rosello et al, 2022).
Autistic children and adolescents who also have ADHD are more likely to experience anxiety, depression, and other mental health conditions than autistic children without ADHD or children with just ADHD (Casseus, Kim and Horton 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).
As clinicians, we recognize that combining autism and ADHD will affect individual and group therapy. Sessions will need to be of shorter total duration and include frequent breaks to sustain attention during therapy sessions (Oerbeck et al, 2021). There is also a greater likelihood of being impulsive and needing more support to implement their new skills in real-life settings (Antshel et al, 2011). The combination will also affect social and emotional group dynamics since each group member is likely to be easily over-stimulated and over-whelmed, leading to more difficulties with self-regulation. Many parents have asked us if their child should be on their medication for ADHD whilst attending their group or individual sessions. We find that the child is far more able to focus and learn from their therapy when they are on their medication, and so we encourage parents to ensure their child has their medication to be ready for the group.
How do I help my child?
Fortunately, there are strategies to maintain and improve attention and executive functioning abilities that can be used at school and home, specifically for autistic children who have ADHD (Kenworthy et al, 2014; Kutscher, 2014). In this article we describe the four components to attention, and how to help your child with each component. We know that physical activity can improve attentional and executive functioning abilities (Pan et al, 2015). Recent research has also confirmed that Yoga can improve executive functions (Tanksale et al, 2021).
Stimulant medication such as methylphenidate (Ritalin) can be beneficial for children who are autistic and have ADHD (Pearson et al, 2020). However, it is important to remember that stimulant medication can affect sleep, appetite and mood, especially irritability. Research on methylphenidate has indicated a positive response rate of 49% of research participants with autism and ADHD but 73% with children with only ADHD (King et al, 2020). There is now a range of new medications for ADHD, such as guanfacine (Intuniv), which may be considered an alternative to methylphenidate, but there are similar side effects.
Attention: What is it and how do we improve it?
Psychologists divide attention into four components: the ability to sustain attention, to pay attention to relevant information, to shift attention when needed, and to encode attention – that is, to remember what was attended to. Autistic children who also have ADHD appear to have problems with all four aspects of attention.
The duration of attention to schoolwork can be an obvious problem, but the degree of attention can vary according to the level of motivation. If the child is attending to an activity associated with their areas of interest, the level of attention can be excessive. The child appears to be almost in a trance of intellectual enjoyment and oblivious to external cues that it is time to move on to another activity or to pay attention to the comments, requests, and instructions of a teacher or parent. The amount of sustained attention can also depend on whether the child wants to give attention to what an adult wants them to do. An autistic child may have his or her own agenda for what to attend to.
Even when an autistic child appears to be attentive to the task set by the teacher, they may not be attending to what is relevant in the material in front of them. Typical children can more easily identify and selectively attend to what is relevant to the context or problem. Autistic children are often distracted and confused by irrelevant detail, and they do not automatically know what to look at. They will need specific instructions as to exactly what to look at in the picture or on the page and important information highlighted in the text.
Some academic activities require the ability to shift attention during the activity and focus on new information. Unfortunately, autistic children can have difficulty ‘changing track’ while engaged in a ‘train of thought.’ There can also be problems with memory processes, such that the learned information is not stored or encoded as well as one would expect. An autistic child may not remember what to attend to when they reencounter the same problem. This characteristic can affect social situations. Autistic children process social information using intellect rather than intuition and can have problems remembering what the relevant social cues are and changing their mental ‘track’ when interacting with more than one person.
An autistic child has considerable problems switching attention to a new activity until there has been closure, i.e., the activity has been successfully completed. Other children appear to be able to pause a thought or activity and move easily to the next activity. In the classroom, autistic children can resist changing activities until they have completed the previous activity, knowing that their thinking cannot as easily cope with transitions without closure. A teacher or parent may need to provide multiple verbal or visual warnings when an activity is going to change, perhaps counting down and, if possible, allowing the autistic child extra time to finish the task.
Remedial programs for autistic children who have problems with attention will include:
- assignments should be broken down into smaller units in keeping with the child’s attention span.
- the teacher or parent supervising homework should regularly monitor and give feedback to maintain attention.
- the number of environmental distractions should be reduced.
- relevant information should be highlighted.
- a quiet, isolated workspace should be provided.
- consideration should be given to the possible value of medication.
Next week, in Part 2 of our artcile we will discuss executive functioning in more detail, what it is, the impacts of difficulties with executive functioning and how to scaffold your child to minimise the impacts.
Where to Now?
If you are interested in learning more, our online course Autism and ADHD covers the latest research on autism and ADHD, the additional strengths and challenges of being autistic and having ADHD, and strategies to cope at school, work, and home.
Angell et al (2021). Journal of Autism and Developmental Disorders 51, 3759-3765
Antshel et al (2011). Journal of Developmental and Behavioral Pediatrics 32, 439-446
Butwicka et al (2017). Journal of Autism and Developmental Disorders 47, 80-89
Casseus, Kim, and Horton (2023). Autism Research
Centers for Disease Control (CDC)
Grandin, T. (1995). Thinking in Pictures and other reports from my life with autism. New York: Doubleday.
Kenworthy et al (2014). Journal of Child Psychology and Psychiatry 55, The Unstuck on Target (UOT) programme
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