The characteristics of autistic spectrum disorder (ASD) can vary both from person to person and across different environments.

They can also be different for the same person at different times in their life. That is why autism is usually referred to as a spectrum disorder.

The traits of ASD can be divided into three main groups. They are:

social interaction

social communication

social imagination

The first characteristics of ASD can sometimes be seen in a child who is under the age of two. However, in other children the condition may not be picked up until they are much older.

Social interaction

A person who has ASD may find it hard to relate to other people. They may:

seem distant or detached

have little or no interest in other people

find it difficult to make friends

not seek affection in the usual way, or resist physical contact such as kissing and cuddling

find it difficult to make eye contact with other people

want to have social contact, but have difficulty knowing how to initiate it

not understand other people’s emotions and have difficulty managing their own emotions

prefer to spend time alone

Social communication

A person who has ASD may have difficulty using verbal and non-verbal skills, and some people may remain non-verbal throughout their lives.

People with ASD who do speak may use speech in an overcomplicated way, using odd phrases or odd choices of words.

They may also make up their own words or phrases, and use more words than are necessary to explain simple things. Someone with ASD may also have difficulty:

expressing themselves well

understanding gestures, facial expressions or tones of voice

using gestures to communicate

understanding instructions

Some people with ASD may develop echolalia, where they repeat words that have little meaning or repeat what has been said to them.

Social imagination

Children with ASD may:

have limited imaginative play

play the same games over and over, or play with games designed for children younger than themselves

get upset if their daily routines are interrupted in any way

show repetitive behaviours, such as hand flapping or spinning

In addition, children and adults may also develop obsessions – for example, with specific objects, lists, timetables or routines.

Sensory difficulties

Most people with ASD also have sensory difficulties. This means they may be oversensitive to specific things, such as touch, certain textures, light levels, or sound.

Sensory difficulties can also lead to problems with movement. A person with ASD may appear clumsy or have an unusual way of walking.

Asperger syndrome

Asperger syndrome is another form of ASD. People with Asperger syndrome will generally not have a learning disability and are often of average or above average intelligence.

They will usually have fewer problems with language development, but may still experience difficulties with social communication.

Asperger syndrome is often diagnosed later in children, and sometimes their difficulties may not be recognised and diagnosed until adulthood. This can cause a delay in getting appropriate support for the individual and their family.