Autism: Information, Facts and Research News

Author: Disabled World (DW)
Updated/Revised Date: 2 Nov 2026

Table of Contents:
Synopsis - Definition - About This Section - FAQs - Publications - Subtopics

Synopsis

Autism is a brain development disorder often characterized by impaired social interaction communication, and restricted repetitive behavior, among other factors.

At a Glance

• 1 - A 2007 study reported that self-injury affected roughly 30% of children with ASD at some point.
• 2 - U.S. prevalence has climbed steadily over two decades, from 1 in 150 children in 2000 to 1 in 31 by the 2022 survey year.
• 3 - Autism is diagnosed about three to four times more often in boys than in girls, and girls are more likely to be diagnosed later.
• 4 - In 2013 the DSM-5 introduced three severity levels for autism spectrum disorder - Level 1 requiring support, Level 2 requiring substantial support, and Level 3 requiring very substantial support.

Topic Definition

Autism

Autism, or autism spectrum disorder (ASD), is a lifelong, non-progressive neurological disorder whose signs usually appear in early childhood. The word "autism" describes a developmental disability that significantly affects verbal and non-verbal communication and social interaction. People with ASD may behave, communicate, interact, and learn in ways that are different from most others. Often, nothing about how they look sets them apart from other people. The classic form of autism involves a triad of impairments; in social interaction, communication, language use, and limited imagination as reflected in restricted, repetitive, and stereotyped behavior patterns and activities.

In 2013, the American Psychiatric Association (APA) released the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The DSM-5 introduced three autism spectrum disorder (ASD) levels of severity:

• Level 1: Requiring support
• Level 2: Requiring substantial support
• Level 3: Requiring very substantial support

Overview

Autism is a brain development disorder characterized by impaired social interaction and communication and restricted and repetitive behavior, with signs that usually appear in early childhood. Older diagnostic manuals separated classic autism from milder conditions such as pervasive developmental disorder not otherwise specified (PDD-NOS), but since the DSM-5 in 2013 they are all diagnosed as autism spectrum disorder (ASD).

Under the older DSM-IV, autism fell under the category of Pervasive Developmental Disorders, which included disorders like Rett Syndrome and Childhood Disintegrative Disorder, and subtypes such as Asperger's Syndrome; the DSM-5 replaced these subtypes with a single spectrum diagnosis.

The number of children diagnosed with autism in America has risen sharply over the last couple of decades, much of it linked to broader diagnostic criteria, greater awareness, and better screening, although considerable debate surrounds the issue of why diagnoses are rising so rapidly. Other proposed causes, such as childhood vaccines, are controversial, and the vaccine hypotheses lack convincing scientific evidence.

U.S. Autism Rates by Year Chart

Autism prevalence studies data table from the ADDM Network for years 2000 to 2020 with combined data from all sites. The Autism and Developmental Disabilities Monitoring (ADDM) Network is a program funded by the U.S. Centers for Disease Control and Prevention (CDC) to collect data to better understand the number and characteristics of children with autism spectrum disorder (ASD) and other developmental disabilities living in different areas of the United States.

Table Showing Yearly Identified Prevalence of Autism Spectrum Disorder in the U.S.

The CDC's yearly figures above track children only. There is no matching year-by-year count for adults - the only national CDC estimate is a one-time model based on 2017 data, shown below.

Source: Centers for Disease Control and Prevention - Estimated Number of Adults Living with Autism Spectrum Disorder in the United States, 2017 (Dietz PM, Rose CE, McArthur D, Maenner M. Journal of Autism and Developmental Disorders, 2020).

Autism and ADHD

Autism and ADHD are different conditions, but they often occur together, and many autistic people also meet the criteria for ADHD. Some symptoms, like inattention, can appear in both. You should not easily confuse someone with ADHD with someone with autism, as their functioning and behavior are different. Autistic individuals display many forms of repetitive or restricted behavior, which the Repetitive Behavior Scale-Revised (RBS-R) categorizes as follows:

• Compulsive behavior is intended and appears to follow the rules, such as arranging objects in a certain way.
• Stereotypy is purposeless movement, such as hand flapping, making sounds, head rolling, or body rocking.
• Sameness is resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted.
• Restricted behavior is limited in focus, interest, or activity, such as preoccupation with a single television program or toy.
• Self-injury includes movements that injure or can injure the person, such as biting oneself. A 2007 study reported that self-injury at some point affected about 30% of children with ASD.
• Ritualistic behavior involves performing daily activities the same way each time, such as an unvarying menu or dressing ritual. This is closely associated with sameness, and an independent validation has suggested combining the two factors.

No single repetitive behavior appears to be specific to autism, but only autism appears to have an elevated pattern of occurrence and severity of these behaviors. Early behavioral or cognitive intervention can help children gain self-care and social and communication skills. There is currently no known cure for autism.

Children and Adults with ASD May:

• Avoid eye contact and want to be alone.
• Repeat actions over and over again.
• Have trouble adapting when a routine changes.
• Not look at objects when another person points at them.
• Not play "pretend" games (for example, not pretend to feed a doll).
• Have trouble expressing their needs using typical words or motions.
• Prefer not to be held or cuddled, or might cuddle only when they want to.
• Have unusual reactions to the way things smell, taste, look, feel, or sound.
• Lose skills they once had (for example, stop saying words they were using).
• Have trouble relating to others or not have an interest in other people at all.
• Appear to be unaware when people talk to them, but respond to other sounds.
• Be very interested in people, but not know how to talk, play, or relate to them.
• Not point at objects to show interest (for example, not point at an airplane flying over).
• Have trouble understanding other people's feelings or talking about their feelings.
• Repeat or echo words or phrases said to them, or repeat words or phrases in place of normal language.

Common Autistic Traits

Behaviorally, certain characteristics identify the autism spectrum. The number of autistic traits determines the severity of autism in the individual. These autistic traits may benefit disciplines like science, mathematics, and engineering.

Social Impairment

• Gullibility
• Lack of eye contact
• Social awkwardness
• Poor ability to make friends
• Brief response to questions
• Indiscriminate social interaction
• Lack of observed desire for friendship

Language Impairment

• Pronoun reversal
• Use of rote chunks of language
• Late or no development of language
• Overly formal and pedantic language
• Odd or monotonous prosody of speech
• Visuospatial thinking, sometimes preferred
• Poor use and understanding of nonverbal communication (i.e., facial expressions and body language).

Imaginative Impairment and Repetitive Adherence

• Preference for routine.
• Perseverative interest or focus.
• Concrete and literal use of language.
• Poor understanding of abstract thought, metaphors, and symbolism.
• Absorption in detail; inability to understand meaning or the whole of a concept.

Sensory Integration Dysfunction

• Self-stimulating mannerisms.
• Fine or gross motor discoordination.
• Peculiar clothing and food preferences.
• Hyper or hyposensitivity of the various senses.

Frequently Asked Questions

At what age does autism usually appear?

Signs of autism usually appear in early childhood, often by age two or three, and autism is lifelong, affecting communication and social interaction.

Is there a cure for autism?

There is currently no known cure for autism, though early behavioral or cognitive intervention can help children gain self-care and social and communication skills.

Do childhood vaccines cause autism?

The vaccine hypotheses are controversial and lack convincing scientific evidence, so childhood vaccines are not established as a cause of autism.

Is autism the same as ADHD?

No, they are different conditions with different patterns of functioning and behavior, although autism and ADHD often occur together.

What is the difference between autism and milder autism spectrum disorders?

Older manuals separated classic autism from milder conditions like PDD-NOS and Asperger syndrome, but since 2013 the DSM-5 diagnoses them all as autism spectrum disorder, with severity described by support levels.

What are the three severity levels of autism spectrum disorder?

The DSM-5 defines Level 1 requiring support, Level 2 requiring substantial support, and Level 3 requiring very substantial support.

Can autistic traits be an advantage in any fields?

Yes, certain autistic traits such as visuospatial thinking and attention to detail may benefit disciplines like science, mathematics, and engineering.

What is masking in autism?

Masking, or camouflaging, is when an autistic person hides or suppresses autistic traits, such as copying others in social situations or holding back stimming. It can be exhausting and is linked to burnout, anxiety, and late diagnosis.

Curated and edited by Ian C. Langtree, Founder and Editor-in-Chief, Disabled World. This section is maintained by the Disabled World editorial team. Last updated: 2 Nov 2026