Core Facts and Features

How common is autism?

Autism was once considered to be rare, but is now recognised as affecting about 1 in 100 of the population. This rise in prevalence over time reflects a much broader definition of autism as a spectrum disorder, changes in diagnostic criteria and improved diagnostic services, although there has also been much discussion of whether there has been any actual change in the rate at which it occurs.


The causes of autism are not known, but genetic and developmental factors are believed to play an important role. ASD is considered to be present from birth, although not usually evident at this stage. There is no ‘cure’ for autism, but there are many ways in which individuals with ASD can be helped and supported to reach their potential and live fulfilling lives.

The hidden nature of ASD

It can be difficult for people to recognise autism and those with ASD may misdiagnosed or labelled as naughty, challenging, loners, eccentric, little professors, emotionally disturbed etc. These types of misunderstandings mean that people can present for diagnosis later in life rather than being diagnosed during childhood.

“All people have assets as well as challenges. There is no such thing as a stereotype"

It is now recognised that ASD is likely to be under diagnosed in females and that ASD may present differently in females.

"People with autism come in as many shapes and sizes as ‘people with pneumonia’. They have different races, social circumstances, intellectual levels, personalities and associated disorders. They should not be expected to conform to a highly specific prototype or to benefit from exactly the same kind of intervention, treatment or training. First and foremost they are people. It so happens that they are affected by the same (or similar) disorder but this does not make them blueprints of each other."

- (Peeters, & Gillberg, 1999)

Individuals with Autism Spectrum Disorder will have difficulties across three main areas.

  • Communication and Language
  • Social interaction and emotional expression
  • Social Imagination

In addition, individuals with ASD may differ from other people in relation to how they process information provided to them verbally or in writing, and their sensory processing may also be different. They may display patterns of restricted and repetitive behaviour.

The term “spectrum” is used to describe the different ways in which ASD affects people at different levels of cognitive ability and at different ages and stages of development.

Communication difficulties

In ASD both verbal and non-verbal communication skills may be affected. It can be difficult for a person with ASD to use language to communicate with others and to understand how other people use language. Some individuals with ASD will be non-verbal, others have more subtle difficulties with communication. This can present as:

  • No apparent interest or attempt in communicating
  • Unusual pattern of language use: Stereotyped, formal or repetitive
  • Lack of understanding as to the reason for communicating
  • Difficulty with understanding what intonation conveys
  • Difficulty engaging in conversations and processing verbal information
  • Language is interpreted literally and the individual finds it difficult to go beyond the actual words to understand what the speaker may have meant
  • Facial expressions and communicative gestures can be confusing for the individual to interpret
  • Difficulty with appreciating the reciprocal (give and take) nature of communication e.g. talking excessively about own interests

See Case Study 2: Younger Child Ellie

Social Interaction and Emotional Expression

People with ASD will have difficulty in understanding social signals or the social significance of behaviour. They will have difficulty in knowing these intuitively and they are hard to teach formally as social rules change with context and setting.

Difficulties with social interaction will depend on the age of the person, his/her developmental level and the severity of the disorder, but these difficulties continue into adulthood and throughout life although in some they become less obvious as their understanding and skills develop.

This can take the form of:

  • Being socially withdrawn and isolated
  • Limited use of non verbal communication in social situations
  • Having difficulty relating to adults or peers
  • Difficulty making and sustaining friendships
  • Appearing very sociable and trying to dominate contact with others yet not being able to get that interaction right
  • Appearing socially awkward and naive
  • Not being able to understand the unwritten social rules
  • Having difficulty predicting or understanding other people’s emotional responses
  • Finding it hard to express their own emotions or doing so in an unusual way

Social Imagination

ASD is characterised by ritualistic behaviours, reliance on routines and extreme delay in, or absence of, social pretend play.

Difficulties can take the form of:

  • Joining in with others in typical pretend play situations in childhood
  • Generalising learning to new situations
  • Problem- solving outside cued rote responses
  • Broadening interests beyond a few narrow, often obsessional or compulsive ones that dominate thinking and behaviour
  • Managing change to familiar routines (e.g. routes; layout; timetables)

Sensory Processing

Some individuals with ASD are over or under sensitive to sensory stimuli which can pose great difficulties in their everyday lives.  For example

  • Oversensitivity to sounds might make it difficult to ignore background noise or tune in to the important aspects of the environment.  Certain loud or unexpected noises might be experienced as painful or stressful e.g. hand driers in toilets, sirens, alarms, tannoy announcements.
  • Oversensitivity can occur for other senses such as touch (e.g.may find clothing labels uncomfortable and unexpected touch distressing) and sight (bright lights or shiny surfaces may be difficult to tolerate)
  • Undersensitivity may lead to seeking sensations e.g. rocking or spinning
  • Those who are under sensitive might not recognise extremes of temperature or pain

It can be difficult to imagine how this is experienced but there are useful video simulations available online.

Visit the Sensory section for more details.

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