OCD, ADHD, and Autism: Understanding the Overlap and the Differences

Disclaimer & a note on language:

I use diagnostic language (OCD & ADHD, 'disorder') for clarity. I use the terms Autistic, or Autism when possible (for reasons that could be it's own blog post). If you see the terms ASD or Autism Spectrum Disorder --- these are direct quotes, or references --- my inclusion of these terms is not an endorsement of deficit-based framing. My hope is that this is useful rather than reductive. Also: this is for educational purposes, not to diagnose or treat.

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Many neurodivergent adults and teens find themselves wondering:

Is this OCD, ADHD, Autism — or all three?

Because these conditions often overlap, it can be hard to tell where one ends and another begins. Understanding the similarities and differences can bring clarity, compassion, and more effective support.

This post highlights what these conditions share — and how they differ — in broad strokes. If you’d like a deeper dive into the clinical nuances and real-world experiences, I’ll be exploring those in my upcoming presentation at MN OCD Conference.

What Is OCD?

Obsessive–Compulsive Disorder (OCD) is characterized by intrusive, unwanted thoughts (obsessions) and repetitive behaviors or mental rituals (compulsions) done to reduce anxiety or prevent a feared outcome.

OCD behaviors are usually driven by fear, uncertainty, or distress, and often feel ego-dystonic — meaning the person doesn’t want to think or act this way but feels compelled to.

Examples might include:

• Mentally reviewing conversations for fear of having said something “wrong”

• Excessive checking, cleaning, or reassurance-seeking

• Silent mental rituals (counting, repeating phrases) to feel “safe”

What Is ADHD?

Attention-Deficit/Hyperactivity Disorder (ADHD) involves differences in how the brain manages attention, energy, and executive functioning.

People with ADHD may experience:

• Difficulty starting or finishing tasks (especially ones that are boring or not interesting to us)

• Periods of hyperfocus on special interests

• Impulsivity or distractibility

• Working memory or organization challenges

ADHD traits are typically ego-syntonic — meaning they feel like part of how someone naturally operates — though they can still cause frustration or burnout.

What Is Autism?

Autism is a neurodevelopmental difference in sensory processing, social communication, and pattern-oriented thinking.

Autistic people might prefer routine or predictability, experience strong interests or “deep dives,” and have differences in sensory experiences (which may present as taking in more of the sensory environment or being hypo-sensitive - and a person can experience both).

Autistic repetition or routines are often self-regulating or soothing, not fear-driven.

Where OCD, ADHD, and Autism Overlap

Because the human brain doesn’t follow diagnostic borders, these conditions often interact and overlap. Some shared experiences include:

• Repetitive thoughts or behaviors

• Difficulty tolerating uncertainty or change

• Differences in executive function (planning, organization, attention, time management)

• Sensory differences - including sensory overwhlem

• Anxiety, perfectionism, or overthinking

While these may look similar on the surface, the motivation underneath matters most.

💡 Example: A person washing their hands repeatedly might be doing so to prevent contamination (OCD), for sensory comfort (Autism), or because they got distracted mid-task and restarted (ADHD).

How Common Is Co-Occurrence?

It’s very common for people to have more than one set of these letters.

• People with OCD are about four times more likely to have autistic traits (Meier et al., 2015).

• Autistic people are at elevated risk for OCD across the lifespan (Wikramanayake et al., 2018).

• Up to 30% of people with OCD also meet criteria for ADHD (Meier et al., 2015).

This overlap can make diagnosis --- and therapy --- tricky, especially when traits mask or mimic each other — but understanding it can transform how people view themselves.

Why Understanding the “Why” Matters

When OCD, ADHD, and Autism coexist, what’s most important isn’t the label — it’s understanding the function of the thought or behavior.

Ask:

• Is it driven by fear or anxiety? → likely OCD

• Is it soothing, regulating, or interest-based? → likely Autism

• Is it tied to attention, energy, or motivation? → likely ADHD

Recognizing the “why” helps clinicians and clients create strategies that support — rather than suppress — neurodivergent needs.

Supporting Neurodivergent Brains Holistically

No single therapy or approach works for everyone. The most effective support honors both differences and overlap.

Therapeutic care might include:

• Psychoeducation about how each condition shows up

• Accommodations for sensory or executive functioning needs

• Adapted therapy methods, like gentle or modified ERP or I-CBT for OCD

• Collaborative therapy pacing, especially when multiple neurotypes are present

  
  

The goal isn’t to “fix” neurodivergence — it’s to foster regulation, autonomy, and self-understanding.

In Summary

OCD, ADHD, and Autism often intertwine in complex and meaningful ways. Recognizing both their shared traits and distinct motivations helps reduce confusion, shame, and self-blame — and opens the door to more personalized care.

In my upcoming presentation, I’ll be discussing:

• How to tell the difference between overlapping traits

• Real-world examples of misinterpretation, and

• Practical, affirming ways to adapt therapy and daily supports

If you’d like to attend head here to get your ticket!

Interested in working an OCD Specialist in MN deeply understands the similarities and differences? Reach out through The Divergent Grove Therapy to explore how we can support your neurodivergent journey.

References

American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.; DSM-5-TR). American Psychiatric Publishing.

Brock, H. (2024). Obsessive-compulsive disorder. In StatPearls. U.S. National Library of Medicine. https://www.ncbi.nlm.nih.gov/books/NBK553162/

International OCD Foundation. (n.d.). Who gets OCD? https://iocdf.org/about-ocd/who-gets-ocd/

Marco, E. J., et al. (2011). Sensory processing in autism: A review. Frontiers in Integrative Neuroscience, 5(49). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086654/

Kushki, A., Anagnostou, E., Hammill, C., Duez, P., Brian, J., Iaboni, A., Schachar, R., Crosbie, J., Arnold, P., & Lerch, J. P. (2019). Examining overlap and homogeneity in ASD, ADHD, and OCD: a data-driven, diagnosis-agnostic approach. Translational psychiatry, 9(1), 318. https://doi.org/10.1038/s41398-019-0631-2

Manning, C., et al. (2015). Enhanced integration of motion information in children with autism. Journal of Neuroscience, 35(18), 6979–6986. https://pubmed.ncbi.nlm.nih.gov/25948250/

Meier, S. M., Petersen, L., Schendel, D. E., Mattheisen, M., Mortensen, P. B., & Mors, O. (2015). Obsessive-Compulsive Disorder and Autism Spectrum Disorders: Longitudinal and Offspring Risk. PloS one, 10(11), e0141703. https://doi.org/10.1371/journal.pone.0141703

Wikramanayake, W. N. M., Mandy, W., Shahper, S., Kaur, S., Kolli, S., Osman, S., Reid, J., Jefferies-Sewell, K., & Fineberg, N. A. (2018). Autism spectrum disorders in adult outpatients with obsessive compulsive disorder in the UK. International journal of psychiatry in clinical practice, 22(1), 54–62. https://doi.org/10.1080/13651501.2017.1354029

Yoshimura, S., et al. (2017). Gray matter volumes of early sensory regions and individual differences in sensory processing. Human Brain Mapping, 38(12), 6206–6217. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6867006/

Zhao, X., et al. (2022). Abnormalities of gray matter volume in adolescents with high-functioning autism spectrum disorder. Neuropsychiatric Disease and Treatment, 18, 717–730. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8983641/