What Is the Difference Between Autism and ADHD?

Autism and ADHD are two of the most commonly diagnosed neurodevelopmental conditions — and they are also two of the most commonly confused with each other. As a psychologist who evaluates both children and adults for autism and ADHD in Seattle, I get this question all the time. The short answer is that autism and ADHD are distinct conditions that can look similar on the surface — and that many people have both. Here is what you need to know.

WHAT IS ADHD?

ADHD — Attention Deficit Hyperactivity Disorder — is a neurodevelopmental condition characterized by persistent patterns of inattention, hyperactivity, and impulsivity that are inconsistent with a person's developmental level and that interfere with functioning across settings. ADHD comes in three presentations: Predominantly inattentive — difficulty sustaining attention, easily distracted, forgetful, loses things, does not follow through on tasks. Predominantly hyperactive-impulsive — fidgets, leaves seat, runs or climbs excessively, talks too much, interrupts, acts before thinking. Combined — meeting criteria for both inattentive and hyperactive-impulsive presentations.

WHAT IS AUTISM?

Autism Spectrum Disorder is a neurodevelopmental condition characterized by differences in social communication and interaction, and the presence of restricted, repetitive patterns of behavior, interests, or activities. Sensory differences are also very common. Autism looks very different from person to person. Some autistic people need significant daily support. Others are highly independent and their autism may not be obvious to casual observers. This is why it is called a spectrum.

WHERE DO THEY OVERLAP?

Both autism and ADHD can involve difficulty with attention and focus, impulsivity, emotional dysregulation, difficulty with executive function skills like planning and organization, social challenges, and sensory sensitivities. This overlap is why the two conditions are so commonly confused — and why a comprehensive evaluation by an experienced psychologist is so important. A checklist or a brief screening tool is often not enough to tell them apart.

HOW ARE THEY DIFFERENT?

The key distinguishing features are in the nature of the social and communication differences. In ADHD social difficulties tend to come from impulsivity, distractibility, or emotional dysregulation — the person understands social rules but struggles to consistently apply them because of attention and impulse control challenges. In autism social differences are more fundamental — they relate to differences in how social information is processed, how nonverbal communication is interpreted, and how relationships are formed and maintained. Autistic people may also have intense specific interests, need for sameness and routine, and sensory experiences that are qualitatively different from ADHD alone.

CAN SOMEONE HAVE BOTH?

Yes — and this is very common. Research suggests that 50 to 70 percent of autistic people also meet criteria for ADHD. Having both conditions is sometimes called AuDHD in the community. When both are present they interact with each other in complex ways and treatment needs to account for both.

WHY DOES IT MATTER WHICH ONE IT IS?

Getting the right diagnosis — or diagnoses — matters enormously for treatment and support planning. ADHD and autism respond to different interventions. Medication may be helpful for ADHD but does not treat autism directly. School accommodations differ. Therapeutic approaches differ. Understanding which condition or combination is driving the difficulties helps families and individuals access exactly the right support.

HOW DO YOU FIND OUT?

A comprehensive psychological evaluation by a psychologist with expertise in both autism and ADHD assessment is the gold standard. At my practice in Seattle I conduct thorough evaluations that carefully assess for both conditions and their interaction — for children as young as 2 through adulthood.

If you are wondering whether your child or you might have autism, ADHD, or both reach out for a free 15-minute consultation at salloni@drsalloni.com or (206) 486-0592.