Dr. Ryan Sultan - ADHD & Autism Expert

ADHD vs Autism: Understanding the Differences, Overlap, and Co-Occurrence

By Dr. Ryan Sultan, MD
Double Board-Certified Psychiatrist (Adult & Child/Adolescent)
Columbia University Irving Medical Center | Integrative Psych NYC


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ADHD and autism are distinct neurodevelopmental conditions that co-occur in 30-80% of cases. ADHD involves executive dysfunction and hyperactivity, while autism centers on social communication differences and repetitive behaviors.


🧩 ADHD vs Autism: More Than Just Confusion

"Do I have ADHD, autism, or both?" This is one of the most common questions I hear from patients—and for good reason. ADHD and autism overlap significantly, with 30-80% of autistic people also having ADHD.

Both conditions can involve:

  • Difficulty with focus and attention
  • Social challenges
  • Executive function problems
  • Emotional regulation difficulties
  • Sensory sensitivities

But they're fundamentally different conditions that require different approaches to treatment. This guide will help you understand the differences—and what it means if you have both.


Table of Contents


Quick Answer: The Core Difference

Aspect ADHD Autism
Core Issue Difficulty regulating attention and controlling impulses Differences in social communication and restricted/repetitive behaviors
In One Sentence "I can't focus on what I should, or I focus too much on what I shouldn't" "I process social information differently and need predictability/routine"
Brain Wiring Difficulty with executive function (planning, organizing, impulse control) Different social cognition (theory of mind, reading social cues) + need for sameness
Biggest Struggle Getting and staying organized, focusing on boring tasks, controlling impulsivity Understanding unwritten social rules, handling social interactions, tolerating change

The Simplest Way to Think About It:

But here's the complication: 30-80% of people with autism also have ADHD. And 20-50% of people with ADHD have autistic traits. They frequently co-occur, which is why distinguishing them is so challenging.


Key Differences Between ADHD and Autism

1. Social Differences

ADHD Autism
Social motivation: Wants friends, enjoys socializing (when not distracted) Social motivation: Variable—may prefer solitude, find socializing exhausting
Social skills: Knows social rules but struggles to apply them due to impulsivity or inattention Social skills: Genuinely doesn't understand unwritten social rules—needs them explicitly taught
Eye contact: May forget to make eye contact (distracted) but understands its importance Eye contact: Finds eye contact uncomfortable or doesn't understand why it matters
Conversation: Interrupts, talks too much, derails conversations (impulsivity) Conversation: Misses social cues, doesn't pick up on hints, takes things literally, struggles with back-and-forth
Reading emotions: Can read emotions but may not notice them (inattention) Reading emotions: Difficulty reading facial expressions, body language, tone of voice
Friendships: Has friends but may lose them due to impulsive behavior or forgotten plans Friendships: Difficulty making friends, prefers solitary activities or one-on-one interaction

Key Question: Do you struggle with social situations because you're distracted/impulsive (ADHD) or because you don't understand the unwritten rules (autism)?

2. Focus & Attention

ADHD Autism
Attention span: Inconsistent—can't focus on boring tasks, hyperfocuses on interesting ones Attention span: Can sustain attention, especially on special interests (may seem like hyperfocus)
Hyperfocus: On whatever is novel, stimulating, or urgent in the moment Intense focus: On specific, narrow interests that are consistent over time
Distractibility: Easily distracted by external stimuli or internal thoughts Focus difficulties: May struggle to shift attention away from interests or routines
Task switching: Jumps between tasks impulsively, starts many things but finishes few Task switching: Difficulty transitioning between activities—prefers to finish one thing fully

Key Question: Is your focus problem "can't sustain attention" (ADHD) or "can't shift attention away from specific interests" (autism)?

3. Repetitive Behaviors

ADHD Autism
Fidgeting: Physical restlessness (bouncing leg, tapping pencil, pacing) to release excess energy Stimming: Self-soothing repetitive movements (rocking, hand-flapping, finger movements) to regulate emotions or sensory input
Repetitive thoughts: Racing thoughts, rumination, mind-wandering Repetitive interests: Deep, narrow focus on specific topics (trains, weather, numbers, etc.)
Routines: Struggles to maintain routines due to forgetfulness and disorganization Routines: Insists on routines—becomes distressed when routines are disrupted
Flexibility: Can be flexible (even if disorganized) Flexibility: Resists change—prefers sameness and predictability

Key Question: Are your repetitive behaviors about releasing energy (ADHD) or self-soothing and maintaining sameness (autism)?

4. Sensory Sensitivities

ADHD Autism
Sensory issues: Some people with ADHD have sensory sensitivities (overlap with autism traits) Sensory issues: Very common—70-95% of autistic people have sensory processing differences
Type: More about distractibility from sensory input (background noise making focus harder) Type: Sensory input can be physically painful or overwhelming (loud noises, certain textures, bright lights)
Tolerance: Can usually tolerate sensory input if focused/medicated Tolerance: Sensory overload can lead to shutdowns or meltdowns

5. Communication & Language

ADHD Autism
Language development: Typical—no delays or unusual patterns Language development: May have delays, advanced vocabulary with poor pragmatics, or echolalia (repeating phrases)
Literal thinking: Understands sarcasm, metaphors, idioms Literal thinking: Often takes things literally—"It's raining cats and dogs" is confusing
Tone of voice: Variable volume/pacing due to impulsivity or excitement Tone of voice: Monotone, unusual prosody, or overly formal speech
Nonverbal communication: Uses gestures and facial expressions appropriately Nonverbal communication: Limited gestures, unusual facial expressions, or difficulty interpreting others'

Overlapping Symptoms That Cause Confusion

Many symptoms appear in both ADHD and autism, which is why they're so commonly confused:

Executive Function Problems

Both conditions involve executive dysfunction—but for different reasons:

Emotional Regulation

Both groups struggle with managing emotions—but the triggers differ:

Social Difficulties

Both can lead to social challenges—but the underlying cause is different:

Hyperfocus vs. Special Interests

This is the most confusing overlap:

Key distinction: ADHD hyperfocus is inconsistent (whatever is stimulating right now). Autism special interests are consistent (same topics over time).


Side-by-Side Comparison Table

Domain ADHD Autism
Core Feature Inattention, hyperactivity, impulsivity Social communication differences, restricted/repetitive behaviors
Social Motivation Wants friends, enjoys socializing May prefer solitude or find socializing exhausting
Eye Contact Forgets due to distraction Uncomfortable or doesn't understand importance
Understanding Social Rules Knows rules but doesn't follow them (impulsivity) Doesn't intuitively understand unwritten social rules
Attention Can't regulate—too scattered or hyperfocused Can sustain attention, especially on interests
Hyperfocus On whatever is novel/stimulating now On specific, consistent special interests
Routines Struggles to maintain routines Insists on routines, distressed by changes
Flexibility Can be flexible (if disorganized) Resists change, prefers sameness
Fidgeting/Stimming Fidgets to release energy Stims to self-soothe or regulate
Sensory Sensitivity Some (20-40%) Very common (70-95%)
Language Development Typical May have delays or unusual patterns
Literal Thinking Understands sarcasm/metaphors Often takes things literally
Emotional Regulation Impulsive reactions, low frustration tolerance Meltdowns from overload, alexithymia
Executive Function Poor planning, forgetfulness, time blindness Difficulty with open-ended tasks, transitions
Onset Symptoms before age 12 (DSM criteria) Early childhood (before age 3 typically)
Prevalence 8-10% of children, 4-5% of adults 1-2% of population
Gender Ratio 3:1 male:female (diagnosed) 4:1 male:female (diagnosed, likely underdiagnosed in females)

Can You Have Both? (Co-Occurrence Rates)

Yes—and it's common.

The Research

What It Looks Like to Have Both

When someone has both ADHD and autism, they experience:

Example: A child who has intense special interests (autism), insists on sameness (autism), but also can't sit still (ADHD), interrupts constantly (ADHD), and forgets to do homework (ADHD).

Why They Co-Occur

Several theories:


How Diagnosis Works: ADHD vs Autism

ADHD Diagnosis (DSM-5 Criteria)

Requires 6 or more symptoms from either inattention or hyperactivity-impulsivity lists (5 for adults):

Inattention symptoms:

Hyperactivity-impulsivity symptoms:

Plus:

See our complete ADHD diagnosis guide.

Autism Diagnosis (DSM-5 Criteria)

Requires deficits in both categories:

A. Social Communication/Interaction (all 3 required):

B. Restricted/Repetitive Behaviors (at least 2 of 4):

Plus:

Diagnostic Process for Both

For ADHD:

For Autism:

When both are suspected: Comprehensive evaluation addressing both sets of criteria, often requiring multiple sessions with a specialist experienced in neurodevelopmental disorders.


Real-Life Scenarios: ADHD Only, Autism Only, or Both?

Scenario 1: Jake, 9 - ADHD Only

Presentation: Jake can't sit still in class. He blurts out answers, interrupts his teacher, and forgets his homework constantly. He has lots of friends but sometimes annoys them by not listening or changing the rules of games impulsively. He understands social cues and feels bad when he hurts someone's feelings—he just acts before thinking.

Key Features:

  • ✅ Hyperactivity and impulsivity
  • ✅ Forgetfulness and disorganization
  • ✅ Social motivation (wants friends)
  • ✅ Understands social rules (just doesn't follow them due to impulsivity)
  • ❌ No sensory sensitivities
  • ❌ No insistence on routines
  • ❌ No special interests

Diagnosis: ADHD, combined type

Scenario 2: Lily, 11 - Autism Only

Presentation: Lily is obsessed with trains. She can tell you every fact about locomotives but struggles with back-and-forth conversation. She doesn't make eye contact and doesn't understand when people are annoyed with her train talk. She can focus for hours on drawing trains but melts down when her routine changes. Loud noises hurt her ears. She has one friend who shares her train interest.

Key Features:

  • ✅ Intense, narrow special interest (trains)
  • ✅ Difficulty with social reciprocity
  • ✅ Avoids eye contact
  • ✅ Insistence on sameness (meltdowns from routine changes)
  • ✅ Sensory sensitivities
  • ❌ Can sustain attention
  • ❌ No hyperactivity or impulsivity
  • ❌ No forgetfulness

Diagnosis: Autism spectrum disorder

Scenario 3: Marcus, 14 - Both ADHD and Autism

Presentation: Marcus loves computers and coding (special interest). He can talk about programming for hours but doesn't notice when people are bored. He also can't sit through class—he fidgets constantly and forgets to turn in assignments even though he completed them. He finds eye contact painful, needs his daily routine to be predictable, and has sensory issues with clothing tags. He interrupts constantly (ADHD impulsivity) and doesn't pick up on social cues (autism).

Key Features:

  • ✅ Special interest in coding (autism)
  • ✅ Social communication deficits (autism)
  • ✅ Sensory sensitivities (autism)
  • ✅ Insistence on routine (autism)
  • ✅ Hyperactivity/fidgeting (ADHD)
  • ✅ Forgetfulness and disorganization (ADHD)
  • ✅ Impulsivity (ADHD)

Diagnosis: ADHD + Autism spectrum disorder (co-occurring)

Scenario 4: Emma, 32 - Borderline/Unclear

Presentation: Emma works in tech and hyperfocuses on coding projects (ADHD-like). She struggles with eye contact (autism-like) but mostly because she forgets to do it when distracted (ADHD-like). She finds small talk annoying (could be either—ADHD finds it boring, autism finds it confusing). She has sensory issues with certain fabrics (autism-like). She's disorganized (ADHD) but also likes routines (autism-like).

Key Features:

  • ? Hyperfocus on coding (ADHD interest-based? Or autism special interest?)
  • ? Eye contact difficulty (ADHD inattention? Or autism discomfort?)
  • ? Dislikes small talk (ADHD boredom? Or autism social deficit?)
  • ? Likes routines but struggles to maintain them

Diagnosis: Requires thorough evaluation—could be ADHD with autistic traits, autism with ADHD traits, or both

The Takeaway: Clear-cut cases are easy to diagnose. Many people fall in the gray area and need comprehensive professional evaluation.


Treatment Differences

ADHD Treatment

Medications:

Therapy:

Accommodations:

See our complete ADHD treatment guide.

Autism Treatment

No medications treat autism core symptoms (social communication, repetitive behaviors). Medications may help co-occurring conditions:

Therapies:

Accommodations:

Treatment When You Have Both

When someone has both ADHD and autism, treatment must address both:

Important: ADHD medication can make autistic people more available for learning (better attention), but it won't change the core autism features.


Common Misdiagnoses

ADHD Mistaken for Autism

Why it happens:

Red flags it's actually ADHD:

Autism Mistaken for ADHD

Why it happens:

Red flags it's actually autism:


What If You Have Both?

If you suspect you have both ADHD and autism:

Getting Diagnosed

Treatment Priorities

  1. Treat ADHD first (medication can improve attention, making other interventions more effective)
  2. Add autism-specific supports (social skills, sensory accommodations)
  3. Address co-occurring conditions (anxiety, depression are common with both)
  4. Build on strengths (many people with both have unique talents)

Self-Advocacy


Frequently Asked Questions

Is ADHD on the autism spectrum?

No. ADHD and autism are separate conditions with different diagnostic criteria. However, they frequently co-occur, and some researchers believe they're part of a broader spectrum of neurodevelopmental differences.

Can ADHD medication help autism?

ADHD medication helps with ADHD symptoms (attention, hyperactivity, impulsivity) but does NOT treat autism core features (social communication, sensory issues, need for routine). If someone has both conditions, ADHD medication can make them more able to participate in autism-focused therapies.

Are people with ADHD more likely to be autistic?

Yes. 20-50% of people with ADHD have clinically significant autistic traits. And 30-80% of autistic people also have ADHD. The overlap is substantial.

Can you outgrow ADHD or autism?

ADHD: Symptoms often decrease with age (especially hyperactivity), but 60-80% of children with ADHD continue to have symptoms in adulthood.

Autism: A lifelong condition. People can learn skills and develop coping strategies, but the core differences remain.

How do I know which one I have?

Professional evaluation is essential. A child psychiatrist, neuropsychologist, or developmental specialist can conduct comprehensive testing to determine whether you have ADHD, autism, both, or neither.

Schedule evaluation with Dr. Sultan in NYC →


Getting Professional Evaluation in NYC

📞 Expert ADHD & Autism Evaluation

Dr. Ryan Sultan, MD is a double board-certified psychiatrist (Adult & Child/Adolescent) with expertise in neurodevelopmental disorders including ADHD and autism spectrum disorder.

Comprehensive Evaluation Includes:

  • Detailed developmental history
  • Observation and clinical interview
  • Standardized rating scales
  • Differential diagnosis (ADHD, autism, or both)
  • Treatment planning and recommendations

Locations:

  • Chelsea: 80 Eighth Avenue, Suite 1501, New York, NY 10011
  • Columbia: 1051 Riverside Drive, New York, NY 10032

Contact:
Email: rs0000@columbia.edu
Phone: 212-305-6001
Book Online at Integrative Psych →


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