Autism spectrum disorder (ASD) is a lifelong neurodevelopmental condition that is being viewed increasingly as an example of neurologic and cognitive variation among people. It is clinically very heterogeneous. It is associated with disabilities and everyday challenges, but may also be associated with cognitive strengths and talents.
Children and adults with ASD have social communication and interaction difficulties and show restricted, repetitive, and stereotyped patterns of behaviors, interests, or activities.
Social communication impairments and ASD behaviors are present during early childhood, but may only become manifest later (e.g., due to increasing impairment).
ASD is a genetic disorder of brain development, but nongenetic factors are also likely to contribute to the phenotype and its heterogeneity.
The aims of treatment are to maximize functional independence and quality of life, and to minimize distress by supporting learning, social communication, and cognitive skills, and by managing any co-occurring physical or mental health problems.
Long-term outcome in adulthood is variable. Many people live either in 24-hour care or with community support (approximately 20%); however, some people with ASD live independent lives (approximately 15%), and some have jobs and families.
Autism spectrum disorder (ASD) is characterized by persistent impairments in social communication, and restricted, repetitive, and stereotyped patterns of behaviors, interests, or activities. Abnormal development is present during early childhood, but may only become manifest later. There may be a history of language disorder or language delay (single-word or phrase speech delay) and some children lose previously acquired language skills (regression). Conversely, some children may develop language at a very early age and have relatively "adult-like" speech. Children who meet the criteria have a diagnosis of "autism spectrum disorder", additionally qualified by level of severity. Approximately 20% to 30% of children develop epilepsy, and between 40% and 80% have intellectual disability (characterized by impaired global intelligence and subsequent impaired social functioning); note that the term "intellectual disability" as used in this topic does not refer to specific learning disorders or disabilities, such as dyslexia or dyscalculia, which may also occur in ASD. Others have ability in the average or above average range. However, many people have an uneven cognitive profile, and show relative cognitive strengths and weaknesses on cognitive testing. In addition to the core symptoms of ASD, the majority of people have coexisting difficulties (e.g., difficulties with sleep or eating). Many young people and adults with ASD have mental health problems such as anxiety and depression. People with ASD may have multiple coexisting problems or conditions concurrently; these associated conditions are often more challenging to manage than ASD itself, but can be a target for intervention or treatment.
History and exam
Key diagnostic factors
- language delay or regression
- verbal and nonverbal communication impairment
- social impairment
- repetitive, rigid, or stereotyped interests, behavior, or activities
Other diagnostic factors
- placid or very irritable as a baby
- feeding difficulties
- unusual posturing
- motor stereotypies
- sensory interests or difficulties
- evidence of other neurodevelopmental disorder
- male sex
- positive family history
- gestational valproate exposure
- genetic variants
- karyotype (chromosomal) abnormalities
- increasing parental age
1st investigations to order
- ASD screening tests
- Childhood Autism Rating Scale (CARS)
- Modified Checklist for Autism in Toddlers (M-CHAT)
- Childhood Autism Screening Test (CAST)
Investigations to consider
- diagnostic questionnaires (e.g., Autism Diagnostic Interview-Revised [ADI-R]; Developmental, Dimensional, and Diagnostic Interview [3di]; Diagnostic Interview for Social and Communication Disorders [DISCO])
- Autism Diagnostic Observational Schedule (ADOS)
- skin examination with Wood lamp
- genetic testing
- MRI brain
- specific testing for genetic disorders (e.g., MECP2 deletion)
preschool children ages 12 months to 5 years (or equivalent developmental age)
school-age children ages 5 to 18 years (or equivalent developmental age)
- Other causes of disordered development/learning difficulties/intellectual disability, or another neurodevelopmental disorder
- Social (pragmatic) communication disorder
- Diagnostic and statistical manual of mental disorders, 5th ed, text revision (DSM-5-TR)
- Autism spectrum disorder in under 19s: support and management
Autism spectrum disorder: information for parents - What is autism spectrum disorder?
Autism spectrum disorder: information for parents - What treatments work?More Patient leaflets
- Log in or subscribe to access all of BMJ Best Practice
Use of this content is subject to our disclaimer