Translated from the Portuguese original. Read the original (Português)
Autism Spectrum Disorder (ASD) is a neurodevelopmental condition present from early in life. It affects, to widely varying degrees, two domains: social communication and interaction and the presence of restricted, repetitive behaviors, interests, or activities. It is not an illness or the result of “wrong” parenting: it is a different way for the brain to process the world, one that can come with many strengths as well as support needs.
Under the DSM-5-TR (the American Psychiatric Association's manual), ASD is characterized by persistent deficits in social communication and social interaction across multiple contexts, together with restricted, repetitive patterns of behavior, interests, or activities. Signs appear early in development and cause functional impairment, with severity specified in levels of support (1, 2, or 3).
What does “spectrum” mean?
You may have seen autism drawn as a straight line, from “mild” to “severe.” That picture is misleading. Autism is multidimensional: each person has their own profile, with some areas needing more support and others being strengths. Two autistic people can be very different from one another.
The two core areas
The diagnosis rests on two dimensions that appear together. Explore each one:
Social communication and interaction
Differences in starting and sustaining conversations, in using and reading gestures, eye contact, and facial expressions, and in building and understanding relationships. This doesn't mean “not wanting” to connect — the desire is often there, but the way of connecting differs from what's socially expected.
Restricted and repetitive patterns
Includes repetitive movements or speech (so-called stereotypies or stimming), strong attachment to routines, very intense and specific interests, and increased or reduced sensitivity to sounds, lights, textures, and smells. These patterns often help the person self-regulate and cope with the environment.
Levels of support
Instead of labels like “mild” or “severe,” the DSM-5-TR describes how much support the person needs in each domain. Tap the cards to see what each level means:
What we know about the causes
Autism has a strong genetic component and relates to brain development. There is no “single cause”: it comes from a combination of many factors. It occurs in all cultures and social classes, and recent estimates point to about 1 in every 36 children (U.S. data, CDC, 2023).
Important myth to debunkVaccines do not cause autism. The study that suggested this was fraudulent and was retracted, and dozens of studies involving millions of children have found no relationship at all. Parenting also does not cause autism.
What helpsEarly, evidence-based interventions — such as behavior-analytic practices, speech-language therapy, occupational therapy, and augmentative and alternative communication — support development and quality of life. The goal is not to “fix” the person, but to expand autonomy, communication, and well-being.
Signs worth paying attention to
Seeking a professional evaluation makes sense when you persistently observe:
- little response to one's own name or to another person's gaze;
- delayed speech or unusual use of language;
- little interest in “pretend” play or in sharing attention;
- repetitive movements and strong discomfort with changes in routine;
- intense reactions to sounds, lights, or textures.
These signs, on their own, do not confirm a diagnosis — evaluation is done by a qualified team, using proper instruments. See the entry on diagnosis and early intervention.
Test your understanding
Quick quiz
Three questions to lock in the concept. You'll see the explanation right away.
Further reading
- American Psychiatric Association. DSM-5-TR: Diagnostic and Statistical Manual of Mental Disorders. 5th ed., text revision, 2022.
- Lord C. et al. “Autism spectrum disorder”. The Lancet, 2018; and Nature Reviews Disease Primers, 2020.
- Centers for Disease Control and Prevention (CDC). Prevalence of Autism Spectrum Disorder — ADDM Network, 2023.
- World Health Organization (WHO). Autism — Fact sheet, recent update.
This entry is educational and does not replace assessment, diagnosis or treatment by a qualified health professional. Every person is unique — for a specific case, seek individual guidance.