Autism spectrum disorder (ASD), more commonly called autism, is a complex diagnosis that affects how people understand and interact with the world around them. Autism affects around 1 in 36 children and as many as 5.4 million adults in the United States alone.
Many people with autism receive a diagnosis in childhood. Others have mild symptoms that don’t become obvious until adulthood. Sometimes, autism symptoms are mistaken for other conditions like [attention-deficit/hyperactivity disorder (ADHD), further delaying an official diagnosis.
Because of confusion around autism diagnosis and treatment, this form of neurodivergence is often misunderstood or misinterpreted. In today’s article, Ability Central clears the air about these misconceptions and explores the most frequently asked questions about autism, including:
What is autism spectrum disorder (ASD)?
How common is autism?
What causes autism?
How is autism diagnosed and treated?
Why is autism commonly undiagnosed or misdiagnosed?
Is autism a sign of low intelligence?
What does it mean to be “neurodiverse”? (Incl What is the difference between “high functioning” autism and “low functioning” autism?)
Does autism cause other conditions?
Where can I get more information about autism?
What is autism spectrum disorder (ASD)?
Autism spectrum disorder, also called ASD or simply autism, is a developmental brain condition that affects how people engage with the world around them. Caused by structural differences in the brain’s development, autism carries a wide range of symptoms and severity.
We call ASD the autism “spectrum” to account for how different the autism experience is from person to person. In the past, psychologists used diagnoses like Asperger’s syndrome or pervasive developmental disorder to categorize “mild” forms of autism. Recent research led to the modern standard, in which all autism-like symptoms and syndromes fall somewhere on the ASD spectrum.
Autism symptoms include:
Lack of interest in other people
Avoiding eye contact
Restrictive or repetitive behaviors
Hyperfixation on certain interests
Difficulty in social situations
Odd or disruptive speech patterns like echolalia
Hand flapping, body rocking, or other self-soothing motions (also called “stimming”)
Difficulty adapting to change, especially unexpected change
Unusual reactions to the way things taste, feel, smell, sound, or look
Food aversions
In children, delayed language, movement, and cognitive/learning skills
To learn more about the symptoms of autism, see How to Recognize Autism Symptoms in Children and Adults.
How common is autism?
As of March 2023, the U.S. Centers for Disease Control (CDC) estimated that 1 in 36 children and 2.21% of adults (5.4 million in the United States alone) have some form of autism spectrum disorder.
This number has more than doubled since 2002, likely due to increases in awareness and understanding of autism spectrum disorders. Updates to diagnostic procedures have made it much easier to diagnose autism in children and adults.
ASD affects people of all ages, genders, sexual orientations, races, and ethnicities. However, recent studies have identified interesting autism statistics:
Autism is 4 times more likely to affect boys than girls.
White children are 19% more likely than Black children and 65% more likely than Hispanic children to be diagnosed with autism.
Compared to cisgender people, people who do not identify with their gender assigned at birth are 3 to 6 times more likely to be diagnosed with autism and other neurodevelopmental disorders.
What causes autism?
Autism is not a result of poor parenting or a child’s upbringing. Autism’s specific causes are still unknown, but [research like the CDC’s Study to Explore Early Development (SEED) suggests](https://www.cdc.gov/ncbddd/autism/facts.html) there may be environmental, biological, and genetic factors in play.
For example, children are at higher risk of developing ASD if they:
Have sibling(s) have autism.
Have other developmental conditions present at birth, like [Fragile X syndrome](https://abilitycentral.org/article/fragile-x-syndrome-fxs-genetic-link-autism).
Experienced birth complications.
Are born to older parents.
Projects like SEED aim to identify autism causes and risk factors, symptom changes over time, and how people with autism function as adults.
How is autism diagnosed and treated?
There is no blood test or medical test to diagnose autism. Instead, doctors use someone’s medical, behavioral, and developmental history (also called an autism screening) to identify symptoms of ASD.
Autism screenings might include:
Developmental monitoring
Screening questionnaires or checklists
Structured tests
Formal evaluations by a child psychologist, speech-language pathologist, or other specialist
To learn more about autism diagnosis and treatment, see How to Recognize Autism Symptoms in Children and Adults and What To Do First After an Autism Diagnosis.
Why is autism commonly undiagnosed or misdiagnosed?
Autism can be an easy diagnosis to miss because symptoms vary so drastically from person to person.
Kids with milder autism symptoms may learn “masking” (hiding their symptoms to appear neurotypical) to fit in at school. Alternatively, ASD might be misdiagnosed as disorders like anxiety, depression, or attention-deficit/hyperactivity disorder.
Underdiagnosis and misdiagnosis is especially common for women and people assigned female at birth (AFAB). Many girls with autism come across as shy, quiet, or introverted. Their symptoms are often mistaken for anxiety, particularly if their ASD behaviors appear in response to stress at school. What’s more, many doctors, teachers, and parents assume ASD primarily affects boys, so they’re not on as close a lookout for autism symptoms in girls.
While ASD is most often diagnosed in childhood, many people with autism do not receive a diagnosis until well into their adult life. According to recent research, adult autism diagnoses and “late childhood” diagnoses (between ages 8 and 14) are on the rise.
Part of this increase may be because many adults who were diagnosed with an intellectual disability in childhood have received updated diagnoses of autism spectrum disorders. In addition, changes to the 2013 Diagnostic and Statistical Manual of Mental Disorders (DSM-5) broadened the medical definition of ASD, making it easier for kids to receive earlier diagnoses.
Is autism a sign of low intelligence?
No. People with autism fall on the same intelligence spectrum as people without autism. That means some children with autism have signs of lower intelligence, including difficulty learning.
Others, however, have high intelligence. They may have difficulties communicating and socializing, but they learn quickly and have excellent memories.
What does it mean to be “neurodivergent”?
The idea of neurodiversity reenforces the fact that there is no “correct” way of thinking. Neurodiverse people simply experience the world in a different way.
In the past, some people divided neurodiverse people like people with autism into “high-functioning” and “low-functioning” categories. High-functioning described people who could speak, write, read, and live independently, while low-functioning referred to people who needed assistance in everyday life.
These descriptors have been phased out in favor of the autism spectrum. Everyone experiences autism differently, so assigning categories like high-functioning or low-functioning created misconceptions and increased stigma around autism.
Examples of neurodiversity besides autism include:
Learning difficulties like dyslexia, dyscalculia, or dysgraphia
Obsessive-compulsive disorder
Does autism cause other conditions?
Autism does not cause other conditions, but it has been linked to many diagnoses with similar symptoms.
Conditions linked to or often co-existing with autism include:
Asthma
Autoimmune diseases like Type 1 diabetes, celiac disease, or rheumatoid arthritis
Ehlers-Danlos syndrome (EDS), a connective tissue disorder that causes mobility issues
Food aversions, sensitivities, and allergies
Gastrointestinal disorders like Chron’s disease or irritable bowel syndrome (IBS)
Migraines and chronic headaches
Processing disorders like receptive language disorder and auditory processing disorder
Skin conditions like eczema or psoriasis
Speech disorders like articulation disorder, echolalia, expressive language disorder, and muteness
Where can I get more information about autism?
To learn more about autism spectrum disorders (ASD), see:
In addition, Ability Central maintains a searchable database of nonprofits that can help with everything from diagnosis to treatment. Use our Service Locator tool to find an organization near you.
For additional information on autism spectrum disorders, see:
