There are three main presentations of ADHD: Predominantly Inattentive (ADHD-I), Predominantly Hyperactive-Impulsive (ADHD-H/I), and Combined (ADHD-C), which includes both inattentive and hyperactive-impulsive symptoms.
ADHD and ASDfrequently co-occur, with studies estimating that 30-70% of individuals with anASD diagnosisalso meet criteria for ADHD. This overlap can lead to significant challenges in diagnosis and treatment, as the symptoms of both disorders can interact and exacerbate each other.
Careful assessment is crucial to identify the presence of both disorders and develop appropriate interventions tailored to the individual’s unique needs.
Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) are both considered neurodiverse conditions, meaning they represent natural variations in brain functioning that can lead to unique strengths and challenges in cognitive, social, and behavioral domains.
Key Points
The main findings of this study on identifying co-occurring ADHD in autism include:
Rationale
ADHD commonly co-occurs with autism, with cooccuring rates ranging from 30-70% (Antshel, Zhang-James, Wagner, Ledesma, & Faraone, 2016; Joshi et al., 2017).
However, ADHD is often under-identified in this population, precluding access to appropriate treatment (Joshi et al., 2017).
Moreover, prior research suggests that commonly used ADHD rating scales may not adequately capturesymptoms in ASD(Yerys et al., 2017).
The current study aimed to identify DSM-5 ADHD presentation prevalence rates in ASD without ID and determine which measures most effectively identify co-occurring ADHD symptoms to inform assessment practices.
Method
This study used archival neuropsychological assessment data from clinically-referred youth with an ASD diagnosis but without ID.
A subset of 210 participants with complete parent/teacher data were further analyzed.
Procedure
Archival data from clinical and research-based assessments were used. Participants’ parents consented to data storage and de-identified use for research. Clinicians used a comprehensive assessment battery to determine ASD and ADHD diagnoses based on DSM-5 criteria.
Sample
The sample included 419 youth (76% male) aged 6-18 years (mean age 11.12) with autism spectrum disorder (ASD) and average overall intellectual functioning (mean FSIQ score of 99.18) referred for neuropsychological evaluation. 61.8% also met the criteria for co-occurring ADHD.
Measures
Statistical Measures
Receiver operating characteristic (ROC) curve analyses compared diagnostic discriminability of measures. Area under the curve (AUC) values indicated diagnostic accuracy.
Results
Insight
This study provides important insights into the prevalence of ADHD presentations in ASD and the effective use of rating scales in identifying co-occurring symptoms.
The high co-occurrence rates, especially of ADHD-Combined presentation, highlight the need for routine ADHD screening in ASD.
However, the limited discriminability of most scales for ADHD-Inattentive symptoms suggests clinicians cannot rely heavily on these questionnaires alone to capture inattention.
Future research should examine item-level scale performance and compare additional measures like the BASC-2 in cooccuring ASD-ADHD.
Strengths
This study had several methodological strengths, including:
Limitations
Despite strengths, this study also came with several limitations, including:
Implications
The high prevalence of co-occurring ADHD in ASD underscores the importance of screening for ADHD symptoms in this population to inform treatment planning.
However, the results suggest rating scales alone are insufficient, especially for identifying ADHD-Inattentive presentation.
Clinicians evaluating ADHD in ASD should use rating scales in combination with detailed clinical interviews and observations to capture inattentive symptoms.
The study also highlights the need for further research to refine ADHD rating scales for use in ASD and examine their long-term predictive validity.
Improved assessment can ensure autistic individuals with cooccurring ADHD receive appropriately tailored interventions and supports.
References
Primary reference
Rau, S., Skapek, M. F., Tiplady, K., Seese, S., Burns, A., Armour, A. C., & Kenworthy, L. (2020). Identifying comorbid ADHD in autism: Attending to the inattentive presentation.Research in Autism Spectrum Disorders,69, 101468.https://doi.org/10.1016/j.rasd.2019.101468
Other references
Antshel, K. M., Zhang-James, Y., Wagner, K. E., Ledesma, A., & Faraone, S. V. (2016). An update on the comorbidity of ADHD and ASD: A focus on clinical management.Expert Review of Neurotherapeutics, 16(3), 279–293.https://doi.org/10.1586/14737175.2016.1146591
Joshi, G., Faraone, S. V., Wozniak, J., Tarko, L., Fried,Joshi, G., Faraone, S. V., Wozniak, J., Tarko, L., Fried, R., Galdo, M., Furtak, S. L., & Biederman, J. (2017). Symptom Profile of ADHD in Youth With High-Functioning Autism Spectrum Disorder: A Comparative Study in Psychiatrically Referred Populations.Journal of Attention Disorders,21(10), 846-855.https://doi.org/10.1177/1087054714543368
Yerys, B.E., Nissley-Tsiopinis, J., de Marchena, A.et al.Evaluation of the ADHD Rating Scale in Youth with Autism.J Autism Dev Disord47, 90–100 (2017).https://doi.org/10.1007/s10803-016-2933-z
Keep Learning
Here are some reflective questions related to this study that could prompt further discussion:
Saul McLeod, PhD
BSc (Hons) Psychology, MRes, PhD, University of Manchester
Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.
Olivia Guy-Evans, MSc
BSc (Hons) Psychology, MSc Psychology of Education
Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.
