New research found that over half of autistic children may also meet the diagnostic criteria for ADHD, but few are assessed for this condition.
Autism spectrum disorder (ASD) is a neurodevelopmental condition that impacts social communication, language, and behaviors. An autistic person can have a wide range of support needs, from minimal to substantial, and this depends on several factors, including verbal language abilities and the level of sensory challenges.
Still, some experts believe autism is a neurodivergent condition and not a disorder, and this has created debate among scientists, healthcare providers, and autistic individuals. Other conditions that fall under the neurodivergent umbrella include dyslexia and attention deficit hyperactivity disorder (ADHD).
Moreover, some autistic individuals may have more than one neurodivergence. For example, a 2023 systematic review and meta-analysis of 340 studies revealed that 37% of children with ASD also had ADHD.
Now, new research published in PLOS One, led by scientists from the University of Glasgow, Scotland, suggests that the number of autistic children with ADHD or other neurodivergent conditions may be much higher.
To conduct the research, the scientists evaluated the medical records of children between the ages of two and 17 years who were referred for autism assessment.
Parents or caregivers were asked to complete the Five to Fifteen (FTF) or Five to Fifteen–Toddler (FTF-T) questionnaire as part of a standard clinical evaluation. In addition, each parent or caregiver completed a comprehensive childhood developmental history form. Then, each child had at least one face-to-face clinical assessment session with an experienced healthcare provider.
Of 114 children referred for assessment, 64 received an autism diagnosis. Out of those 64 individuals, questionnaires showed that 76.2% potentially had at least one other underlying neurodivergence in addition to ASD.
Specifically, 55.6% had evidence of a possible ADHD-like neurotype, 52.4% showed possible motor differences, and 36.5% had indications of a potential learning difficulty or disability.
Still, only 26.3% were formally investigated for an additional underlying diagnosis.
Though the study analyzed a small number of participants, it highlights the need for more recognition and assessment of co-occurring neurodevelopmental disorders in autistic individuals.
"This is a very comprehensive study with significant findings and confirmation of the overlap between ADHD and ASD. In my clinical experience, I have seen similar rates, especially in the adult demographic," says Dr. Pablo Jeczmien, FRCPsych Consultant Psychiatrist and Psychotherapist and founder of the Harley Row Clinic, London, Surrey, and Sussex, UK, who was not involved in the study.
Holistic assessments that diagnose both conditions could help identify individuals with ASD and ADHD and lead to more tailored interventions.
"Having one assessment that encapsulates both diagnostic criteria could be more efficient and, indeed, holistic," Jeczmien tells Healthnews, "Interestingly, at our practice, we are considering having just one assessment for children which would combine the ASD and the ADHD assessment. This is particularly relevant in children under 5, since it is very difficult to differentiate between the two conditions at that age."
For individuals diagnosed with ASD and ADHD, psychoeducational coaching can be an effective intervention, Jeczmien suggests.
"The educational element helps patients and families learn about their unique diagnosis and understand why and how their brain works," he explains. "The coaching element is a chance to learn tools and actions to reduce the challenges of neurodiversity and harness strengths."
Psychotherapy and coaching can also address unique emotional experiences related to ASD and ADHD, especially for adults diagnosed later in life.
Additionally, Jeczmien suggests that a holistic treatment plan should include nutritional therapy since 50% of ASD children have gastrointestinal disorders.
"Studies have found that making simple dietary changes like boosting Omega 3-6, magnesium, zinc, and B6 can be helpful for managing the symptoms of ADHD," Jeczmien says. "Our clinical experience supports the approach that having an appropriate diet to rebalance the microbiome can also help."
- Neuroscience & Biobehavioral Reviews. Prevalence of co-occurring conditions in children and adults with autism spectrum disorder: A systematic review and meta-analysis.
- PLOS One. Towards system redesign: An exploratory analysis of neurodivergent traits in a childhood population referred for autism assessment.
- University of Glasgow. Three Quarters of Autistic Children Also Have Other Types of Neurodivergence.