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ADHD, Autism and Asperger’s: Know the Differences

ADHD, Autism, Asperger’s

Attention deficit hyperactivity disorder (ADHD), autism and Asperger's syndrome are all neurodevelopmental disorders. But there are very important — and in some cases, dramatic — distinctions between the three conditions. A proper diagnosis is crucial because it can have a significant effect on a person’s development and function, beginning in childhood and continuing throughout their entire life.

ADHD is more prevalent than autism spectrum disorder (ASD, which includes autism and Asperger’s), affecting 9 percent of children ages 4 to 17 as well as 4 percent of adults, according to the National Alliance on Mental Illness (NAMI). By comparison, ASD affects 1 to 2 percent of the population, according to the U.S. Centers for Disease Control and Prevention (CDC).

Understanding the terminology: ADD, ADHD, ASD, autism and Asperger’s

ADHD: ADHD, which was sometimes called attention deficit disorder (ADD), is characterized by hyperactivity and impulsivity. While most children demonstrate some of the behaviors associated with ADHD at times, those with ADHD have six or more symptoms of hyperactivity and impulsivity, according to the Cleveland Clinic. And for a child to be diagnosed with ADHD, their symptoms must cause problems in more than two settings (such as home, school and church) and manifest before age 12. ADHD is not an ASD.

Autism: Autism, or ASD, is a condition that develops during childhood and adversely affects a person’s communicative and socializing skills. Those with ASD demonstrate limitations with or repetition of certain behaviors, hobbies or activities. The “spectrum” refers to how much the symptoms and behaviors of ASD vary from person to person, according to NAMI. Some people are barely affected by the symptoms while others are gravely affected to the point of disability. According to the CDC, 1 of every 59 8-year-old children in the United States has ASD. Boys are far more likely than girls to develop it. The disorder is indiscriminate, affecting all demographic and socioeconomic groups.

Asperger’s: Asperger's syndrome, sometimes referred to as Asperger’s, is no longer used as a separate diagnosis, according to Autism Speaks. It is now under a larger diagnosis of ASD, as it is characterized by similar behaviors and struggles. With Asperger’s, people can face challenges relating to social situations and deviation from routine, but often have strong language skills and intellectual ability. Asperger’s was first included in the American Psychiatric Association’s (APA's) Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) in 1994 as a disorder distinct from autism. However, in its 2013 update to the DSM, the association included Asperger’s as a form of ASD.

What they share in common and how they differ

Like ASD, ADHD is a neurodevelopmental disorder. Unlike ASD, however, ADHD is not a spectrum disorder. While those affected by ADHD do exhibit symptoms of hyperactivity and impulsivity, they do not face the intellectual and language challenges faced by those with autism or the communicative and socializing challenges faced by people with autism and Asperger’s.

Within the ASD spectrum, there are many distinctions between the disorders. Symptoms of Asperger’s are less severe than the symptoms of autism.

People with autism can seem distant and uninterested in communicating with others. In contrast, those with Asperger’s typically have a desire to fit in and communicate with peers, but can struggle to do so, according to the Autism Society. They can come across as socially awkward, have trouble understanding social norms and demonstrate a lack of empathy. In some cases, those with Asperger’s may avoid eye contact, appear unengaged in conversation and struggle to understand verbal or physical cues.

A significant difference between Asperger’s and autism is that people with Asperger’s do not have a delay in speech. They do not face the degree of difficulty with language, and communication in general, experienced by those with autism. In fact, children with Asperger’s often have good language skills — they just utilize language differently. For example, their patterns of speech may seem unconventional, lack inflection or have a different cadence.

Cognitive ability is another area where autism and Asperger’s differ. Unlike people with autism, those with Asperger’s do not experience cognitive delays that are considered to be clinically significant. Some people with Asperger’s have higher-than-average intelligence.

Diagnosing ADHD, Asperger’s and autism

Determining whether a child has a neurodevelopmental disorder — and if so, which disorder — requires a methodical process.


The following steps are taken when diagnosing ADHD, according to the Cleveland Clinic:

  • Identify symptoms and behaviors that take place in a child’s natural settings, like home and school
  • Eliminate other potential causes of the symptoms
  • Identify other conditions that may be affecting the child along with the main symptoms

Based on the groups of symptoms that a child shows, the doctor will diagnose the type of ADHD. There are four main types:

  • Combined ADHD, which includes inattention, impulsivity and hyperactivity. People with combined ADHD show signs of all three. Combined is the most common type of ADHD.
  • Primarily hyperactive/impulsive ADHD
  • Primarily inattentive ADHD (previously called ADD)
  • Other ADHD


Diagnosing autism is more complicated than diagnosing ADHD. This is because, initially, children with autism can appear to have a mental disability, issues with vision and hearing or sensory processing problems.

An early and correct autism diagnosis is extremely important and helpful for the child because it will serve as the foundation for an effective treatment program.

A medical diagnosis of autism is made by a doctor after a careful evaluation of symptoms and diagnostic tests, notes the Autism Society. To make a diagnosis of autism, doctors typically rely on the APA’s DSM. Typically, more than one appointment is needed to properly assess a child’s cognitive ability and behavior. A thorough diagnosis will also rely on insight from family, teachers and other people who regularly interact with the person being diagnosed.

Some parents may seek an evaluation of their child in their school setting, which is different from a medical diagnosis. For an educational evaluation, a determination is usually made by a team of professionals, and the goal is to figure out whether the child would benefit from special education.


While diagnoses of Asperger’s have proliferated in recent years, it is unclear whether this means that the disorder is becoming more common or if medical professionals have become more adept at diagnosing it, the Autism Society says. Prior to the APA’s decision to include Asperger’s in the ASD spectrum, the same symptoms were listed for both of the disorders, despite the fact that people with Asperger’s do not show delays in the development of language skills.

In fact, a person must have both normal language development and normal intelligence to be diagnosed with Asperger’s. The latest requirements for a diagnosis of Asperger’s include severe and ongoing issues with social interaction as well as limited and repetitive patterns of behavior and interests and activities that lead to clinically significant deficiency in social or employment situations.

If you suspect that your child or someone you know may have Asperger’s or another neurodevelopmental disorder, the first step is to arrange for an initial assessment of their behavior and developmental history by a qualified medical professional. An early diagnosis is important — children diagnosed early have a better chance of success in many aspects of life.

Article references

  1. Cleveland Clinic, Attention-Deficit/Hyperactivity Disorder (ADHD): Diagnosis and Tests -
  2. National Alliance on Mental Illness, Autism -
  3. National Institute of Mental Health, Autism Spectrum Disorder (ASD) -
  4. Autism Speaks, What Is Asperger Syndrome? -
  5. Autism Society, Diagnosis -
  6. Autism Society, Asperger’s Syndrome -
  7. National Alliance on Mental Illness, ADHD -
  8. Centers for Disease Control and Prevention (CDC), Autism Spectrum Disorder: Data and Statistics -