The main signs of autism are differences in how autistic people communicate and interact with others.

Autism is a spectrum condition, which means that it affects people in different ways.

But most autistic people see, hear and experience the world differently from other people.

Although the signs of autism vary widely among children, young people and adults, there are 2 common characteristics:

  • difficulties with social communication and interaction – autistic people may find it hard to join in conversations or to make friends
  • repetitive behaviour, routines and activities – such as fixed daily routines, repetitive body movements and a hypersensitivity to certain sounds

Autistic people may also be under- or oversensitive to certain sounds, lights, colours and other things, known as sensory sensitivity.

These signs are present over time and have a noticeable effect on daily life.

See a GP or health visitor if you notice any of the signs of autism in your child or you're concerned about your child's development.

You can also talk to your child's teacher or care worker.

If you're an adult and are concerned about signs of autism in yourself, talk to a GP.

Possible signs of autism in pre-school children

The signs given here do not necessarily mean your child is autistic. And autistic children may not show all the signs.

Spoken language

  • delayed speech development (for example, speaking less than 50 different words by the age of 2) or not speaking at all
  • repeating set words and phrases
  • speech that sounds monotonous or flat
  • communicating using single words, despite being able to speak in sentences

Responding to others

  • not responding to their name being called, despite having a hearing test showing normal hearing
  • rejecting cuddles initiated by a parent or carer (although they may initiate cuddles themselves)
  • reacting unusually negatively when asked to do something by someone else

Interacting with others

  • not being aware of other people's personal space, or being unusually upset by people entering their own personal space
  • limited interest in interacting with other people, including children of a similar age
  • not enjoying situations other children of their age enjoy
  • preferring to play alone, rather than asking others to play with them
  • difficulties using and understanding gestures, body language and facial expressions when communicating
  • avoiding eye contact

Repetitive or unusual behaviour

  • having repetitive movements, such as flapping their hands, rocking back and forth, or flicking their fingers
  • playing with toys in a repetitive or unexpected way, such as lining blocks up in order of size or colour, rather than showing imaginative play
  • preferring to have a familiar routine and getting very upset if there are changes to this routine
  • having a strong like or dislike of certain foods based on the texture or colour of the food as much as the taste
  • over- or undersensitivity to sensory stimuli, such as sounds, smells, colours and lights

Possible signs of autism in school-age children

The signs given here do not necessarily mean your child is autistic. And autistic children may not show all the signs.

Spoken language

  • avoiding using spoken language
  • speech that can sound monotonous or flat
  • speaking in pre-learned phrases, rather than putting together individual words to form new sentences
  • a tendency to dominate conversations with others, focusing on topics that are of particular interest to the child

Responding to others

  • taking people's speech literally and finding it difficult to understand sarcasm, metaphors or figures of speech
  • reacting very negatively when asked to do something by someone else

Interacting with others

  • being less aware of other people's personal space, or being very upset by people entering their own personal space
  • appearing to have little interest in interacting with other people, including children of a similar age, or having few close friends, despite attempts to form friendships
  • not understanding how people usually interact socially, such as greeting people or saying goodbye
  • finding it hard to adapt the tone and content of their speech to different social situations – for example, speaking very formally at a party then speaking to total strangers in a familiar way
  • not enjoying situations and activities that a lot of children of their age enjoy
  • rarely using gestures, body language or facial expressions when communicating
  • avoiding eye contact

Unusual or repetitive behaviour

  • repetitive movements, such as flapping their hands, rocking back and forth, or flicking their fingers
  • playing in a repetitive or seemingly unimaginative way
  • often preferring to play with objects rather than people
  • developing a highly specific interest in particular subjects or activities
  • preferring to have a familiar routine and getting very upset if there are changes to their normal routine
  • having a strong like or dislike of certain foods based on the texture or colour of the food as much as the taste

Find out more about how autism is diagnosed in children

Possible signs of autism in adults

The signs given here do not necessarily mean an adult is autistic. And autistic adults may not show all the signs.

Interacting with others

  • not always understanding social "rules"
  • understanding "personal space" differently
  • feeling anxious or stressed in social situations
  • finding it hard to judge "appropriate" interactions, such as being either too formal or too familiar
  • finding it difficult to make friends and keep them
  • lack of eye contact or too much

Communication

  • speech may have a different stress or pitch
  • use of repetition
  • asking questions that other people might find inappropriate

Unusual or repetitive behaviour

  • preferring or being reliant on routine
  • feeling anxious or stressed at changes that may seem minor to other people
  • having particular or very focused interests
  • finding rituals helpful
  • finding it hard to understand abstract concepts, such as time and choice

Autistic adults are more likely to have had problems staying in education or finding and staying in work.

Find out more about diagnosis of autism in adults

Page last reviewed: 04/02/2019
Next review due: 04/02/2022