What is autism spectrum disorder?
What to know about diagnosing, treating, and supporting a person with autism.
- Reviewed by Rebecca P. Thomas, PhD, Contributor
- Alina von Korff, MD, Contributor
- Carol Weitzman, MD, Contributor
Autism is a neurodevelopmental condition that affects a person’s ability to communicate and interact with others, often involving challenges with starting and maintaining conversations, intense focus on special interests, and repetitive language or behaviors. It’s called a spectrum because individuals with autism can present with a range of strengths and challenges: some may benefit from support in building social awareness, while others may require continual and comprehensive care.
What are the signs and symptoms of autism?
Autism presents in each person differently, but there are some common characteristics, including:
- difficulty making eye contact or incorporating nonverbal communication (such as gestures, pointing, facial expressions) with speech
- repetitive or “scripted” speech (using dialogue from movies or TV in real-life conversations)
- challenges with social-emotional reciprocity, like taking turns or understanding subtle cues around personal space or conversational expectations
- repetitive movements like pacing or hand flapping
- intense interest in special topics and difficulty moving to new topics or activities
- trouble coping with changes in routines or schedules and a need for things to be highly predictable.
What causes autism?
There is no proven single cause for autism. Rather, research shows that complex genetic and environmental factors come into play. Multiple genes have been found to be associated with autism. Studies have also shown that there is a strong hereditary component, meaning that genetic issues that contribute to autism may run in families.
While environmental factors alone have not been shown to cause autism, several factors such as premature birth and advanced parental age are associated with autism risk. It is also important to note that a person cannot “catch” autism. Finally, there is no evidence that vaccines cause autism.
How is autism diagnosed?
According to the Centers for Disease Control and Prevention, autism affects one in 31 children under the age of 8, most of whom are diagnosed before age 5. Changes in diagnostic criteria and public awareness over the last 30 years have contributed to increases in the number of individuals diagnosed as adults. Another factor is greater awareness that girls on the autism spectrum may have symptoms that are different than those in boys.
The Autism Diagnostic Observation Schedule (ADOS) is one tool used to diagnose autism, and it can be used at any age. There are other evidence-based methods that can be used to diagnose children with autism as well.
If you have a child who shows symptoms of autism spectrum disorder (ASD), talk with your pediatrician, who can assess your child’s development and determine if further evaluation is required.
Understanding an autism diagnosis
Doctors use diagnostic criteria that describe a person’s social communication and interaction abilities, and the presence of restricted and/or repetitive behaviors. The diagnosis is further refined with three broad levels that describe the amount of support a person requires in their social communication and restricted/repetitive behaviors:
- Level 1 autistic people require some support. They can communicate verbally and fluently but often have difficulty initiating social interactions. They may find it challenging to read the emotions or intentions of others. Level 1 autistic individuals can be emotionally rigid and may struggle to make transitions between topics in conversation and in moving from one activity to another.
- Level 2 autistic people require substantial support. They have difficulty communicating verbally and nonverbally, have significant social challenges, and require more assistance in managing home, school, and work environments.
- Level 3 autistic people require very substantial support and possess severe deficits in verbal and social communication. These individuals have intense behavioral needs and require significant care and supervision.
The language of autism is constantly evolving. While describing autism using level 1, 2, and 3 is not well standardized, it’s important to know the risks of saying that an autistic person is low-, moderate-, or high-functioning. While Level 3 is now commonly referred to as “profound autism,” there’s not useful terminology at this point for levels 1 and 2.
Autism and intellectual disabilities do not always go hand in hand, and in fact are separate diagnoses that require additional testing. An autism diagnosis does not automatically indicate intellectual impairment.
People with autism can have “splintered” skills that indicate they are gifted in one way and significantly impacted in another. Many nonverbal autistic people can be highly intelligent and emotionally engaged, for example, while some autistic people are extremely introverted and have difficulty with relationships even though they possess brilliant technical skills. Individuals who have completely normal intellectual abilities but also struggle with symptoms of autism may be more likely to develop depression.
Boys are three times more likely to have an autism diagnosis. Some evidence suggests that autism looks different in girls, and women may be better able to compensate for their challenges. This can contribute to delays in diagnoses among females.
Who can diagnose autism?
Providers from a range of disciplines (pediatricians, neurologists, psychiatrists, clinical psychologists, neuropsychologists) can make an autism diagnosis. More recently, due to long wait times for specialist evaluation, primary care clinicians are being trained to diagnose autism, particularly in young children with symptoms that strongly suggest autism. There are numerous tests that can provide useful data when diagnosing autism and creating a support plan.
What treatments and therapies are available for autism?
Autism cannot be cured, but there are a range of therapies that can be used to address the specific challenges that accompany it. Young children benefit from therapies provided by early intervention programs. School-age children, teens, and young adults can find support through schools and medical providers.
There are several evidence-based behavioral treatments that can help children with autism. Applied Behavioral Analysis (ABA) is the most well-known and most studied treatment. This approach can support children and youth with autism by reinforcing desired behaviors in various settings. Its core principles rely on shaping behaviors such as social skills and improved coping. The goal is to build and reinforce skills and independence while also reducing challenging behaviors that interfere with day-to-day activities.
Speech and language therapy can help autistic people communicate both verbally and nonverbally. Some people with autism use augmentative and alternative communication (AAC) devices, which can range from a communication board with static pictures to an interactive tablet that generates speech.
Occupational and physical therapies can help with fine motor skills (like handwriting and typing), gross motor skills (such as balance and coordination), sensory accommodations (tools that help individuals cope with busy, noisy, or crowded places), and daily living skills. These therapies also help integrate all these skills in school, home, and work settings.
Social skills training helps with interpersonal communication, allowing autistic people to improve their social awareness so they can better understand and respond to social situations.
Children with autism may not respond to medications as well, and are more likely to experience medication side effects compared with non-autistic children.
Common conditions and special considerations
Autistic people are more likely to have certain co-occurring conditions, including:
- attention deficit hyperactivity disorder
- learning disabilities
- anxiety and depression
- gastroesophageal reflux disease (GERD)
- constipation
- migraine headaches.
Autistic people can also experience pain differently, making it sometimes difficult for them to communicate about their health. Behavioral problems can indicate an underlying health condition, and significant changes in mood or irritability, particularly in nonverbal people, should be addressed with a doctor.
Medication for autism
There are no medications that can “cure” autism. There are, however, FDA-approved medications approved specifically for managing other conditions that are common in people with autism such as ADHD, anxiety, and irritability or aggression.
Living with autism: Support and resources
Greater autism awareness and changes in diagnostic criteria over time have led to some adults seeking a diagnosis. An official diagnosis may empower adults to get the support they need to improve their relationships, win employment accommodations, and advocate for autism-competent health care.
Autistic people and their families can find support in the educational and medical environments that guide them to community resources called “wraparound services,” including mental health care, government programs, service providers, employment, housing, and more.
Autism is a lifelong condition, but with attention and advocacy for good health and good care, it can be treated and managed in ways that lead to a fulfilling life for those who have it and for those who love and care for them.
About the Author

Sarah Campbell, Senior Research Coordinator, TEAMS
About the Reviewers

Rebecca P. Thomas, PhD, Contributor

Alina von Korff, MD, Contributor

Carol Weitzman, MD, Contributor
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