ADHD, autism, and OCD are three distinct conditions that often share overlapping traits. This overlap raises a growing question in psychology: should these diagnoses be seen as part of a broader neurodivergent spectrum?
In this article, we explore where they intersect, how they differ, and what it means for diagnosis, treatment, and identity.
Key Takeaways
- ADHD, autism, and OCD are distinct conditions, but they share overlapping traits like executive dysfunction, sensory sensitivities, and repetitive behaviors.
- Many individuals meet criteria for more than one diagnosis, with high rates of co-occurrence between ADHD and autism, and between autism and OCD.
- Despite surface similarities, the underlying causes of certain behaviors—like hyperfocus or rituals—differ across conditions.
- Accurate diagnosis is essential, as treatments for one condition (e.g., ADHD medication) may worsen symptoms of another (e.g., OCD).
- Understanding both the overlaps and the differences helps ensure more personalized support, reduce misdiagnoses, and validate diverse neurodivergent experiences.
Overlapping Traits and Experiences
Despite being defined as separate disorders, ADHD, autism, and OCD share many common threads.
These overlapping traits can sometimes blur diagnostic lines and contribute to misdiagnoses or late diagnoses. Some of the most common include:
- Executive Function Challenges: Difficulties with planning, organizing, time management, and self-regulation are common in both ADHD and autism, and even individuals with OCD can struggle when obsessive thoughts hijack their focus.
- Sensory Sensitivities: Sensory issues tend to be more pervasive in autism, but also appear in ADHD and OCD. Individuals may be overwhelmed by noise, textures, or bright lights.
- Social Difficulties: Many people with ADHD or autism experience challenges in social interactions due to different reasons — autism involves deeper challenges with reading cues, while ADHD impulsivity can disrupt communication. OCD can cause social withdrawal due to anxiety.
- Intense Interests and Hyperfocus: Focusing deeply on things of interest is common. Autistic individuals often have passionate special interests, ADHDers hyperfocus, and people with OCD may become preoccupied with intrusive thoughts or rituals.
“I’m not convinced that autism, ADHD and OCD are actually separate things. I think in the coming years we’ll find they’re very much related, if not different sides of the same coin.”
These overlapping traits mean that a person who is autistic might also seem inattentive and impulsive, or a person with OCD might also have sensory sensitivities or need routines like someone with autism.
Coexisting conditions
Up to half of people diagnosed as autistic also show ADHD symptoms, and about two-thirds of people with ADHD have some autistic characteristics, according to one study.
“My clinical experience suggests it’s more than three-quarters in both directions,” notes Dr. Jessica Eccles of the Royal College of Psychiatrists, referring to the overlap between ADHD and autism.
There’s also significant overlap between autism and OCD: one UK study found that nearly 47% of OCD patients had clinically significant autistic traits.
Similarly, research shows up to 30% of people with OCD may also have ADHD, and about 20% of people with ADHD show symptoms of OCD.
Different Diagnoses: What Sets ADHD, Autism, and OCD Apart?
Despite the similarities, each condition has its own defining features. Understanding these differences is key to getting the right diagnosis and support.
ADHD
ADHD is a neurodevelopmental condition marked by inattention, impulsivity, and hyperactivity. People with ADHD often:
- Get easily distracted
- Struggle with time management
- Crave novelty and stimulation
- Talk or move constantly
- Interrupt or act on impulse
Socially, ADHDers are usually eager to connect with others, but impulsivity can get in the way. They’re not typically driven by anxiety or rigid thinking—though they can struggle with follow-through and emotional regulation.
Autism
Autism primarily affects social communication, sensory processing, and behavior patterns. Autistic individuals may:
- Find eye contact or small talk uncomfortable
- Prefer routines and predictability
- Experience strong sensory aversions or fixations
- Develop deep, focused interests
- Engage in repetitive behaviors for comfort
Unlike OCD, these behaviors are not anxiety-driven—they’re usually calming or enjoyable. Social motivation varies: some autistic people want close friendships, others may be more solitary, and that’s okay.
OCD
OCD is an anxiety disorder involving obsessive thoughts and compulsive behaviors. Key features include:
- Repetitive, intrusive thoughts (e.g., fear of contamination)
- Rituals or behaviors performed to reduce anxiety (e.g., excessive cleaning)
- Distress when rituals can’t be performed
- Awareness that the thoughts or behaviors are excessive
Unlike autism or ADHD, OCD often begins later (usually in adolescence or early adulthood) and is driven by a cycle of fear and attempted relief—not by routine or impulsivity.
So while all three can involve repetitive behaviors or trouble focusing, the underlying reasons are different: comfort (autism), stimulation-seeking (ADHD), or fear (OCD).
It’s worth noting that diagnostic labels evolve. Autism itself used to be separated into sub-diagnoses (Asperger’s syndrome, PDD-NOS, etc.), but these were merged into one umbrella diagnosis “Autism Spectrum Disorder” in 2013.
ADHD has types (inattentive, hyperactive, combined) but is one diagnosis. OCD stands alone but is recognized to overlap with related conditions (like tic disorders or hoarding disorder).
As science advances, the distinctions between these conditions may be re-drawn – or perhaps drawn with dotted lines instead of solid ones.
The Science Behind the Overlaps
What does research say about why ADHD, autism, and OCD intersect so often?
Here’s a look at what science has uncovered about the overlaps and differences:
Genetic Overlap
Large studies show autism and ADHD share many common genetic variants. Twin and family studies estimate 50–70% genetic overlap, which helps explain why these conditions often appear in the same families.
One analysis found shared genetic markers between autism, ADHD, and Tourette’s—but not OCD, which surprisingly showed no significant genetic link to autism and a negative correlation with ADHD.
This suggests OCD may involve different genetic pathways or rare variants. Still, the frequent co-occurrence of autism and OCD hints at more complex interactions.
Brain Networks and Neurocognition
Neuroimaging shows overlapping brain circuit differences in ADHD and autism—especially in executive function areas like the frontal lobes. Both often involve issues with attention, impulse control, and flexibility.
OCD, however, shows distinct overactivity in the orbitofrontal cortex and basal ganglia, linked to intrusive thoughts and compulsive behaviors.
While autism also involves social processing regions like the amygdala, ADHD shows differences in dopamine systems and the default mode network.
Each condition reflects disruptions in brain connectivity, but with different cognitive outcomes.
Cognitive & Behavioral Profiles
ADHD, autism, and OCD share certain traits—like difficulty switching attention—but differ in their behavioral patterns.
Autism tends toward rigidity, ADHD toward impulsivity, and OCD toward fear-driven compulsions. Yet these traits can overlap in individuals, pointing to shared cognitive dimensions.
While similarities exist, studies show distinct profiles, such as autism’s hallmark social difficulties and specific repetitive behaviors, which help clinicians differentiate between them.
One “Neurodivergent” Umbrella? – The Debate on Merging vs Separating
Given the overlap among ADHD, autism, and OCD, some suggest uniting them under a single “neurodivergent” label, while others argue for keeping them distinct. Let’s look at both perspectives.
The Case for Merging
The neurodiversity movement, originating in the 1990s, promotes viewing brain differences like autism, ADHD, and increasingly OCD as part of natural variation—not disorders.
Advocates argue that using one umbrella term reduces stigma, encourages a focus on strengths, and helps individuals feel validated and less fragmented by multiple diagnoses.
Some suggest unified terminology could streamline services and promote earlier, more comprehensive assessments.
For example, diagnosing OCD might prompt screening for ADHD or autism, helping identify co-occurring conditions earlier. Holistic support could then replace siloed services, reflecting the reality that many individuals span more than one category.
The Case for Separation
Distinct diagnoses guide effective treatment. ADHD, autism, and OCD have unique clinical profiles and evidence-based interventions.
Merging them under “neurodivergence” could obscure these differences—like confusing the treatment for ADHD with that for OCD.
Diagnostic manuals (DSM-5, ICD-11) still list them separately for this reason. There’s also concern about public misunderstanding—such as assuming ADHD is a “type” of autism.
Many autistic self-advocates see autism as an identity, while those with OCD may view it as an illness to manage, not a core part of self.
A single label risks flattening these identity differences and erasing community-specific support.
Cultural & Stigma Considerations
Labels shape perception. In some cases, people prefer certain terms due to societal stigma—like choosing ADHD over autism due to perceived severity.
A unified label might blur stigma, but also introduce confusion. Each community (autism, ADHD, OCD) has its own culture and resources.
Some worry that an umbrella approach could dilute this or that we’re already defaulting to vague, overbroad labels (e.g., autism absorbing traits once labeled as ADHD or Asperger’s).
A Middle Ground
Many clinicians now take a hybrid approach—acknowledging overlaps without erasing distinctions. It’s common to screen for ADHD in autistic patients and vice versa, and dual diagnoses are increasingly accepted.
Emerging research frameworks look at shared traits (like compulsivity or attention-switching) across diagnoses.
For now, separate labels remain essential, but with growing recognition that these conditions exist on intersecting spectra.
Implications for Treatment, Support, and Self-Understanding
Whether we view ADHD, autism, and OCD as distinct or part of one spectrum isn’t just semantics – it has real-life implications for those affected:
How we group ADHD, autism, and OCD—under one neurodivergent umbrella or as separate conditions—has real-life consequences.
Diagnosis & Treatment
Seeing these conditions as part of a shared neurodivergent profile could lead to more integrated care, helping people with overlapping traits avoid fragmented support.
For instance, someone with attention issues and compulsive behaviors might benefit from a coordinated treatment plan.
But too broad a label may overlook specific needs—precise diagnoses often unlock services like school accommodations or therapy coverage.
The ideal is a balanced approach: recognize overlap, but assess comprehensively to avoid missing co-occurring traits.
Accommodations & Support
Distinct labels help tailor educational and workplace supports—such as sensory-friendly tools for autism, time management help for ADHD, or flexibility for OCD.
A generic “neurodivergent” label risks flattening those differences. Still, it could encourage more personalized support if approached thoughtfully.
Many accommodations—like clear instructions or quiet spaces—benefit all three groups and can be applied flexibly across diagnoses.
Medication & Therapy
Each condition has different treatment needs. ADHD meds might worsen OCD symptoms, while OCD treatments may miss autistic traits.
If clinicians rely solely on an umbrella label, there’s a risk of imprecise care. A hybrid strategy works best: understand shared traits, but identify dominant features to guide treatment.
Personal Identity & Community
Some embrace “neurodivergent” as a unifying, empowering label. It can reduce stigma and build solidarity across conditions.
Others prefer diagnosis-specific identities that offer clearer community and validation. Both are valid. However, we must avoid minimizing individual differences.
People with an autism and ADHD diagnosis often describe their traits clashing—like intense focus clashing with forgetfulness—highlighting the need for nuanced understanding, not just broad categories.
Framing & Stigma
This debate also touches on how we frame these conditions. OCD is often seen as a treatable mental illness, while autism and ADHD are increasingly viewed as lifelong neurotypes.
Merging them might blur those distinctions, which could either reduce stigma—or create new misunderstandings.
That’s why many advocate for change led by lived experience: “Nothing about us without us.”
Finding the Balance: Embracing Complexity
The umbrella debate is ultimately about how best to support neurodivergent people. ADHD, autism, and OCD clearly overlap, and recognizing those links can build empathy—like shared struggles with sensory overload or routines.
Unified, neurodivergent individuals can push for broader acceptance and accommodations. Still, each condition also brings unique traits, and keeping diagnoses distinct allows for more precise support and celebration of those differences.
Experts envision a future where diagnosis becomes more dimensional—assessing traits like attention, sensory processing, or anxiety individually, rather than relying on one label.
ADHD, autism, and OCD might then be seen as overlapping profiles within a larger neurodevelopmental spectrum.
For now, what matters most is understanding and support. If a broad label helps you feel seen, that’s valid.
If specific terms clarify your needs, that’s equally valid. Many people share traits across these diagnoses—it’s more common than you might think. As science evolves, so may our language.
But one thing won’t change: every brain is valid, and honoring that complexity is key. Embracing the full picture—not forcing simple answers—may be the best way forward.
References
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Mayes, S. D., Calhoun, S. L., Mayes, R. D., & Molitoris, S. (2012). Autism and ADHD: Overlapping and discriminating symptoms. Research in Autism Spectrum Disorders, 6(1), 277-285. https://doi.org/10.1016/j.rasd.2011.05.009
Sokolova, E., Oerlemans, A. M., Rommelse, N. N., Groot, P., Hartman, C. A., Glennon, J. C., … & Buitelaar, J. K. (2017). A causal and mediation analysis of the comorbidity between attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Journal of autism and developmental disorders, 47, 1595-1604. https://doi.org/10.1007/s10803-017-3083-7
Wikramanayake, W. N. M., Mandy, W., Shahper, S., Kaur, S., Kolli, S., Osman, S., … & 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
