Misdiagnosis of ADHD and ASD: Why It Happens and How We Can Improve

When children show signs of struggling with attention, social interaction, or behavior regulation, parents and teachers often wonder: Is this Attention-Deficit/Hyperactivity Disorder (ADHD), or could it be Autism Spectrum Disorder (ASD)?

Both are among the most common neurodevelopmental conditions. However, due to overlapping symptoms, many children are misdiagnosed—or diagnosed much later than they should be. This misdiagnosis can lead to incorrect treatments, delayed interventions, and unnecessary stress for families.

The Overlap Between ADHD and ASD

At first glance, ADHD and ASD can look very similar:

• Shared Traits: Difficulties with executive functioning, sensory sensitivities, emotional regulation challenges, and sometimes repetitive movements (often referred to as “stimming”).

• ADHD-Specific Traits: Impulsivity, hyperactivity, a craving for novelty, and rapid shifts in attention.

• ASD-Specific Traits: Preference for routines, restricted interests, social-communication difficulties, and repetitive behaviors.

The overlap between these traits is substantial. A child who struggles to focus, talks excessively, or has meltdowns in overwhelming environments could fit criteria for either condition—or both.

How Common Is Co-Occurrence?

Research shows that ADHD and ASD frequently co- occur: Around 50–70% of children with ASD also exhibit ADHD symptoms (Ghamdi & AlMusailhi, 2024), and about 13% of children initially diagnosed with ADHD are later diagnosed with ASD as well (Ghamdi & AlMusailhi, 2024). This presents clinicians with a tricky challenge: what appears to be “just ADHD” could be ASD—or both. Without a thorough assessment, children risk having only part of the issue addressed.

Delayed ASD Recognition

One major consequence of this overlap is a delayed ASD diagnosis. A large-scale study (Kentrou et al., 2018) found that children who were initially diagnosed with ADHD received an ASD diagnosis approximately 1.8 years later than children diagnosed directly with ASD. The gender difference is significant as well. The delay was more pronounced for girls: about 2.6 years, compared to 1.5 years for boys (Ghamdi & AlMusailhi, 2024; Kentrou et al., 2018). For adults, prior ADHD did not significantly affect timing of diagnosis, but ASD recognition was still notably delayed overall (Ghamdi & AlMusailhi, 2024; Kentrou et al., 2018). This gender gap highlights another important issue: girls often camouflage their ASD symptoms, masking difficulties by imitating peers or following social scripts. As a result, clinicians may misinterpret these children as having ADHD or anxiety, overlooking ASD altogether.

What’s at Stake When Misdiagnosis Happens

Getting the wrong diagnosis is not just a labeling problem—it alters the course of care:

• Medication Mismatches: A child misdiagnosed with ADHD may be prescribed stimulants, which do not address ASD-related rigidity or communication challenges.

• Overlooked Co-occurrence: Many children meet the criteria for both conditions, but if only one is recognized, interventions remain incomplete.

• Mental Health Risks: Misdiagnosed individuals face higher risks of anxiety, depression, and even suicidality (Ghamdi & AlMusailhi, 2024).

• Missed Early Interventions: The earlier ASD is identified, the more effective specialized therapies can be. Delayed recognition means losing valuable developmental time (Ghamdi & AlMusailhi, 2024).

Why It’s Difficult to Distinguish

Part of the challenge lies in the brain itself. Studies show that:

• Both conditions involve differences in regions such as the basal ganglia and amygdala.
• Both conditions exhibit white matter disruptions, though in slightly different areas.
• EEG studies suggest ADHD is linked to impaired inhibition, while ASD is more closely related to social processing networks (Ghamdi & AlMusailhi, 2024).

While ADHD and ASD share neurobiological features, they also follow distinct developmental pathways. Clinically, however, these differences are not always apparent.

How Clinicians Can Improve Accuracy

Improving diagnostic accuracy requires a multidimensional approach. Clinicians benefit from collaborating within multidisciplinary teams that include psychologists, psychiatrists, social workers, and speech-language specialists, ensuring that diverse perspectives are considered. Using structured tools such as the ADOS-2, ADI-R, CPT-3, and BRIEF-2 helps capture symptoms systematically across various domains (Kentrou et al., 2018). Additionally, collecting detailed developmental histories is crucial, as understanding how behaviors evolve over time can help clarify whether they align more with ADHD, ASD, or both. Another critical step is adopting gender-sensitive approaches, recognizing that girls often camouflage their difficulties in ways that make ASD less visible and more likely to be mistaken for ADHD or anxiety  (Ghamdi & AlMusailhi, 2024). Finally, educating caregivers about the similarities and differences between ADHD and ASD empowers families to advocate effectively and ensures that treatment planning is both accurate and comprehensive.

Conclusion

ADHD and ASD overlap in many ways, but they are distinct conditions. Misdiagnosis can result in incorrect treatments, delayed interventions, and serious mental health consequences.

By recognizing co-occurrence, considering gender differences, and adopting multidisciplinary, structured assessments, we can achieve more accurate diagnoses—and ultimately, better outcomes for children and families.

References

Ghamdi, K. A., & AlMusailhi, J. (2024). Attention-deficit hyperactivity disorder and Autism Spectrum Disorder: Towards Better diagnosis and management. Medical Archives, 78(2), 159. https://doi.org/10.5455/medarh.2024.78.159-163.

Kentrou, V., De Veld, D. M., Mataw, K. J., & Begeer, S. (2018). Delayed autism spectrum disorder recognition in children and adolescents previously diagnosed with attention-deficit/hyperactivity disorder. Autism, 23(4), 1065–1072. https://doi.org/10.1177/1362361318785171.