Autism is a lifelong developmental disability. On its own, autism is not a learning disability or a mental health problem. But some people with autism have an accompanying learning disability, learning difficulty or mental health problem.
Autism is a spectrum condition. This means that while all people with autism share certain difficulties, the condition affects each person differently.
One of the best known forms of autism is Asperger syndrome. People with the condition are often of average or above-average intelligence. They have fewer speech problems than people with other types of autism, but may find it difficult to understand and process language.
While some people with autism live independent lives, others may need a lifetime of specialist support. Autism can have a profound and sometimes devastating effect on individuals and families. However, getting the right support makes a substantial difference to the person who is diagnosed and their loved ones.
What causes autism?
There are more than half a million people with autism in the UK, around 1 in every 100 people. If you include their families, autism touches the lives of over two million people each day.
The causes of autism are still being investigated. According to the National Autistic Society (NAS), there is strong evidence to suggest autism can be caused by a variety of environmental or neurological factors, all of which affect brain development. There is also evidence to suggest genetic factors are responsible for some forms of autism.
What we do know is autism is not caused by a person's upbringing and is not the fault of those with the condition.
There is no cure for autism. But there are numerous interventions (learning and development techniques) that can help.
Read more about what may cause autism.
How does autism affect people?
Autism affects the way a person communicates with and relates to other people. It also affects how they make sense of the world around them.
Everyday life for people with autism can be confusing, frightening and lack meaning. They often find understanding and communicating with others particularly difficult, which can leave them feeling isolated.
People with autism may also experience some form of sensory sensitivity or a lack of sensitivity - for example, to sound, touch, taste, smell, light or colour.
They can experience a wide range of symptoms, which are often grouped into two main categories.
Problems with social interaction and communication
This can include problems understanding and being aware of other people's emotions and feelings. It can also include delayed language development and an inability to start conversations or take part in them properly.
Restricted and repetitive patterns of thought, interests and physical behaviours
This can include making repetitive physical movements, such as hand tapping or twisting, and becoming upset if these set routines are disrupted.
Children, young people and adults with autism are often also affected by other mental health conditions, such as attention deficit hyperactivity disorder (ADHD), anxiety or depression.
About half also have varying levels of learning difficulties. However, with appropriate support many people can be supported to become independent.
Children with more severe symptoms and learning difficulties are likely to need more care and assistance to live independently as adults.
Other related characteristics of autism
Love of routines
The world can seem an unpredictable and confusing place to people with autism, which is why they often feel more comfortable with a fixed daily routine, so they know what's going to happen each day.
People with autism may experience sensory sensitivity in one or more of the five senses - including sounds, sights and smells - which they can find stressful. A person's senses are either intensified (hypersensitive) or lack sensitivity (hyposensitive). For more information on sensory sensitivity in autism, visit the NAS website.
Many people with autism have intense special interests, often from a young age. These can be anything, from art or music to trains and computers.
People with autism may have learning disabilities that can affect all aspects of their life, from studying in school to learning how to wash themselves or make a meal.
Where can I get more information?
For more information on autism, read our advice on living with autism, which includes information about getting an autism diagnosis in childhood and adulthood, as well as stories from people affected by the condition.
Article provided by NHS Choices