ADHD and Autism Together: How Co-Occurring ASD Changes the ADHD Diagnosis Process

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During our recent webinar, ADHD Without the Shame: From Diagnosis to Empowerment, attendees submitted dozens of insightful questions about ADHD assessment, treatment, and life beyond diagnosis. While we addressed many of them live, we wanted to ensure every question received a thoughtful response. This blog series is our way of continuing that conversation. In this post, we're focusing on questions related to if ADHD is diagnosed differently in a people with Autism Spectrum Disorder—exploring the evidence, clarifying misconceptions, and offering practical guidance. Your questions deserve answers rooted in both science and compassion.

Is ADHD Diagnosed Differently in Someone with Autism?

The short answer: while the core diagnostic criteria for ADHD remain the same, the process of identifying ADHD in someone with Autism Spectrum Disorder (ASD) is often more complex and requires careful clinical judgment.

Understanding the Overlap

Research suggests that a significant percentage of individuals with autism also meet criteria for ADHD (Leitner, 2014). Because of this overlap, clinicians must carefully assess whether attention, impulsivity, or executive functioning challenges are best explained by ADHD, ASD, or both (Antshel & Russo, 2019).

For example:

• Difficulty focusing could stem from ADHD-related inattention
• Or it could be related to sensory sensitivities or intense interests seen in ASD
• Impulsivity might reflect ADHD, or differences in social understanding of ASD

This is why assessment is not just about checking boxes, but understanding the why behind the behaviour.

What Stays the Same in Diagnosis

ADHD is diagnosed using standardized criteria, such as those in the DSM-5-TR (APA, 2022), which include:

• Persistent patterns of inattention and/or hyperactivity-impulsivity
• Symptoms present across multiple settings (e.g., home, school, work)
• Evidence that symptoms impact functioning

These criteria do not change based on whether someone also has ASD.

What Looks Different in Practice

While the criteria stay the same, the assessment process is often more nuanced when ASD is present:

1. Differential diagnosis matters more
Clinicians must determine whether symptoms are better explained by autism, ADHD, or both. This often involves gathering detailed developmental history and input from multiple sources (parents, teachers, self-report).

2. Masking and compensation can complicate things
Many individuals, especially teens and adults, develop strategies to cope or “mask” their difficulties. This can make ADHD symptoms less obvious, particularly in those who have already adapted to living with ASD.

3. Executive functioning challenges may overlap
Both ADHD and ASD can involve difficulties with planning, organization, and task initiation. The difference often lies in the pattern and underlying drivers of those challenges.

4. Social context is interpreted differently
In ADHD, inattention in social situations may look like distractibility. In ASD, it may reflect differences in social communication or processing. Clinicians consider these distinctions carefully.

Why Dual Diagnosis Matters

Historically, ADHD and ASD were not always diagnosed together. We now know that recognizing both can lead to more effective, individualized support.

A dual diagnosis can help:

• Clarify why certain strategies haven’t worked
• Guide more tailored interventions (e.g., combining structure + sensory supports)
• Reduce self-blame by offering a more accurate understanding of one’s brain

Practical takeaways

If you’re wondering whether ADHD might be present alongside autism, here are a few helpful considerations:

• Look for patterns across settings, not just one environment
• Notice whether challenges are consistent over time or situation-dependent
• Consider a comprehensive assessment rather than relying on quick screenings
• Seek clinicians experienced in both ADHD and ASD when possible

Final Thoughts

ADHD and ASD frequently co-occur (Antshel & Russo, 2019). ADHD is not diagnosed differently in someone with ASD, but it is understood more contextually. The goal isn’t just to assign labels, but to build a clearer picture of how someone thinks, processes, and navigates the world.

When ADHD and ASD are both recognized, support can become more precise, compassionate, and effective.

Disclaimer: This post is for education and self-awareness. It is not a diagnosis or replacement for therapy.

References
American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.; DSM-5-TR). https://doi.org/10.1176/appi.books.9780890425787

Antshel, K. M., & Russo, N. (2019). Autism spectrum disorders and ADHD: Overlapping phenomenology, diagnostic issues, and treatment considerations. Current Psychiatry Reports, 21(5), 34. https://doi.org/10.1007/s11920-019-1020-5

Leitner, Y. (2014). The co-occurrence of autism and attention deficit hyperactivity disorder in children: What do we know? Frontiers in Human Neuroscience, 8, 268. https://doi.org/10.3389/fnhum.2014.00268