Autism spectrum disorder (ASD) involves a range of impairments in social interaction, communication and behaviour.
Autism spectrum disorder is defined in the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition). It takes previously recognised diagnoses (Asperger’s disorder, autistic disorder and pervasive developmental disorder) and groups them into one spectrum.
The severity of ASD varies. Some individuals require minimal support and have average or above-average intellectual ability. This was previously known as Asperger’s disorder. Others can be severely affected and require substantial or very substantial support.
Features
The features of ASD vary significantly between individuals along the spectrum. They can be categorised as deficits in social interaction, communication and behaviour. Features are usually observable from early childhood.
Deficits in social interaction may include:
- Lack of eye contact
- Delay in smiling
- Avoiding physical contact
- Unable to read non-verbal cues
- Difficulty establishing friendships
- Not displaying a desire to share attention (e.g., not playing with others)
Deficits in communication may include:
- Delay, absence or regression in language development
- Lack of appropriate non-verbal communication (e.g., smiling, eye contact, responding to others and sharing interest)
- Difficulty with imaginative or imitative behaviour
- Repetitive use of words or phrases
Deficits in behaviour may include:
- Repetitive behaviour and fixed routines
- Anxiety and distress with experiences outside their regular routine
- Stereotypical repetitive movements (e.g., self-stimulating movements, such as hand-flapping or rocking)
- Intense and deep interests that are persistent and rigid
- Greater interest in objects, numbers or patterns than in people
- Extremely restricted food preferences
Diagnosis
An autism specialist should make the diagnosis. Diagnosis usually involves assessment by child psychiatrists, clinical psychologists or paediatricians with a special interest. It involves a detailed evaluation of the child’s current and historical behaviour and communication.
Management
Autism spectrum disorder is a lifelong condition. Management depends on the severity of the condition. Patients with mild impairments may be highly functioning and not require any formal support.
A multidisciplinary team can help support patients and carers (e.g., parents) with greater impairments. For example:
- Child and adolescent mental health services (CAMHS)
- Psychologists
- Speech and language specialists
- Dieticians
- Paediatricians
- Social workers
- Specially trained educators and special school environments
- Charity organisations (e.g., National Autistic Society)
Last updated February 2026
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