ADHD and ASD – A review of comorbid diagnoses in children

ADHD and ASD – A review of comorbid diagnoses in children

By Ms. Toneya Ashby, Psychologist

Individuals on the Autism Spectrum often present with additional diagnoses, which are referred to as comorbidities. One of the most common comorbid diagnoses for an individual with ASD is Attention-Deficit/Hyperactivity Disorder (ADHD). Research suggests that between 37-85% of individuals with ASD will also present with features of ADHD (Leitner, 2014). As a result of this statistic, ADHD is commonly screened for at Minds and Hearts when undertaking an ASD diagnostic assessment.

Research has suggested that children with comorbid diagnoses of ASD and ADHD experience:
• More significant executive dysfunction than individuals with a single diagnosis of ASD
o Including poorer inhibitory control, sustained attention, verbal working memory, and cognitive flexibility
• Greater difficulty with Theory of Mind (the ability to attribute mental states such as beliefs, desires, feelings, and intentions of others) than individuals with a single diagnosis of ADHD
o Including recognising facial emotions
• More behavioural problems than individuals with a single diagnosis of either ASD or ADHD
o Including aggression, delinquent behaviours, conduct problems, and oppositional behaviours

Individuals with either ASD or ADHD as a single diagnosis will experience a range of challenges and difficulties across the lifespan associated with their symptoms; however, this line of research emphasizes that the comorbid occurrence of both diagnoses brings with it a more complex presentation, with some significant differences in the challenges and difficulties experienced.

The authors argue that effective treatment is reliant on the accurate diagnosis of both disorders, and that a multi-disciplinary approach to treatment is used. Children with comorbid diagnoses of ASD and ADHD have greater treatment needs than children with a single diagnosis (Zablotsky, Bramlett & Blumberg, 2017), and are at risk of missing necessary supports when they are not assessed and treated for both disorders.

If you or your child’s teacher have noticed difficulties with inattention (such as difficulty paying attention, organising one’s belongings, listening to others, or making careless mistakes) and/or with hyperactivity or impulsive behaviour (such as difficulty playing quietly, constant movement or fidgeting, interrupting others, or showing poor self-control), it may be useful to undergo an assessment for ADHD.

Research article:
Berenguer, C., Rosello, B., Colomer, C., Baixauli, I., & Miranda, A. (2018). Children with autism and attention deficit hyperactivity disorder. Relationships between symptoms and executive function, theory of mind, and behavioural problems, Research in Developmental Disabilities, 83, pp. 260-269.