Co-Occurring ADHD in Autistic Children

Co-Occurring ADHD in Autistic Children

Interest in the co-occurrence of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) has grown in the last decade. Both are neurodevelopmental disorders with onset of symptoms in early childhood. Research, practice and theoretical models indicate that these disorders frequently overlap and co-occur. For example, studies conducted in the US and Europe indicate that children with ASD in clinical settings present with comorbid (co-occurring) symptoms of ADHD with rates ranging between 37% and 85%. In fact, ADHD is a relatively common initial diagnosis in young children with ASD. Some researchers suggest that there are sub-groups of children with ASD with and without ADHD symptoms.

More severe externalizing, internalizing and social problems, as well as more impaired adaptive functioning, and more autistic traits and maladaptive behaviors have been reported in children with both ASD and ADHD than children identified with only ASD. For example, school-age children with co-occurrence of ASD and ADHD were significantly more impaired than children with only ASD on measures of cognitive and social functioning, as well as in the ability to function in everyday situations. Symptoms included inattention, impulsivity, hyperactivity and other features such as low frustration tolerance, poor self-monitoring, temper and anger management problems, and mood changes in the classroom. They were also more likely to have significant cognitive delays and display more severe autism mannerisms, such as stereotypic and repetitive behaviors in comparison with children identified with only ASD.

It is imperative that practitioners recognize the high co-occurrence rates of these two disorders as well as the potential increased risk for social and adaptive impairment associated with comorbidity of ASD and ADHD. Children with the combined presence of ASD and ADHD may need different treatment methods or intensities than those with ASD only in order to achieve better outcomes.

If clinically significant ADHD symptoms are identified, and social development does not appear to be responding to intervention, changes in the intervention pro­gram (e.g. intensity, strategies, and goals) may be required. It is also important to note that a significant change in the DSM-5 is removal of the DSM-IV-TR hierarchical rules prohibiting the concurrent diagnosis of ASD and ADHD. When the criteria are met for both disorders, both diagnoses are given. Thus, an assessment of ADHD characteristics should be included whenever inattention and/or impulsivity are indicated as presenting problems. 

Although the social deficits of autism are typically described as being “reciprocal” in nature and those of ADHD are considered to be the result of inattention and disinhibition, the distinction is not always easy to make in real-world practice. In addition to rating scales, an examination of the child’s neuropsychological characteristics and profile may be helpful in identifying the comorbidity of ASD and ADHD. For example, a comprehensive developmental assessment may include measures of neuropsychological functions such as working memory, planning and strategy formation, cognitive flexibility, response inhibition, and self-regulation. More research is needed to further clarify the behavioral characteristics of children with co-occurring ASD and ADHD so that specialized treatments and interventions may be designed to improve outcomes and quality of life for this group of children. Further information on best practice guidelines for assessment of ASD is available from A Best Practice Guide to Assessment and Intervention for Autism Spectrum Disorder in Schools (2nd Edition)

Key References and Further Reading

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.) Washington, DC: Author.

Colombi, C., & Ghaziuddin, M. (2017). Neuropsychological Characteristics of Children with Mixed Autism and ADHD. Autism Research and Treatment, 1-5. 

Doepke, K. J., Banks, B. M., Mays, J. F., Toby, L. M., & Landau, S. (2014). Co-occurring emotional and behavior problems in children with Autism Spectrum Disorders. In L. Wilkinson (Ed.), Autism Spectrum Disorders in Children and Adolescence: Evidence-based Assessment and Intervention in Schools (pp. 125-148). Washington, DC: American Psychological Association.

Kuhlthau K., Orlich F., Hall T.A., et al. (2010). Health- Related Quality of Life in children with autism spectrum disorders: results from the autism treatment network. Journal of Autism and Developmental Disorders, 40(6), 721–729.

Loveland K. A., Tunali-Kotoski, B. (2005), The school age child with autism. In F. R. Volkmar, R. Paul, A. Klin, & D. Cohen (Eds.), Handbook of autism and pervasive developmental disorders: Vol. 1. Diagnosis, development, neurobiology, and behavior (3rd ed., pp. 247-287). New York: Wiley.

Murray M.J., (2010). Attention-deficit/hyperactivity disorder in the context of autism spectrum disorders. Current Psychiatry Reports, 12(5), 382–388.

Rao, P. A., & and Landa, R. J. (2014). Association between severity of behavioral phenotype and comorbid attention deficit hyperactivity symptoms in children with autism spectrum disorders. Autism, 18, 272-280.

Sikora, D. M., Vora, P., Coury, D. L., & Rosenberg, D. (2012). Attention-Deficit/Hyperactivity Disorder Symptoms, Adaptive Functioning, and Quality of Life in Children With Autism Spectrum Disorder. Pediatrics, 130, S91-97. DOI: 10.1542/peds.2012-0900G

Wilkinson, L. A. (2017). A best practice guide to assessment and intervention for autism spectrum disorder in schools. London & Philadelphia: Jessica Kingsley Publishers.

Lee A. Wilkinson, PhD, is a licensed and nationally certified school psychologist, and certified cognitive-behavioral therapist. He is author of the award-winning books,  A Best Practice Guide to Assessment and Intervention for Autism and Asperger Syndrome in Schools and Overcoming Anxiety and Depression on the Autism Spectrum: A Self-Help Guide Using CBT. He is also editor of a text in the APA School Psychology Book Series, Autism Spectrum Disorder in Children and Adolescents: Evidence-Based Assessment and Intervention in Schools. His latest book is A Best Practice Guide to Assessment and Intervention for Autism Spectrum Disorder in Schools (2nd Edition).