How can you tell if an adult is autistic?

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1. What is autism?

Autism is a developmental disorder that affects how people interact with others. People with autism tend to find social situations difficult, and to prefer narrow and repetitive activities.

Our modern ideas about autism began in the 1940s, when the term was used to describe children with emotional and social problems. Since then, our approach has become more nuanced. Diagnosis can be difficult, and there may be many adults with autistic spectrum disorder (ASD) who were not diagnosed in childhood, when our understanding of autism was narrower.

Children and adults, men and women, and people of all levels of intellectual ability can have ASD. Today there are around 700,000 people in the UK who know they have the condition.

2. What do experts look for to diagnose ASD?

There is no biological test for autism spectrum disorder. Instead, experts ask questions to explore someone’s social interaction and understanding. To make a diagnosis of autism, experts look for two kinds of behaviour.

Social behaviours

ASD affects the way people interact and communicate, and can be evident from early childhood. In adults, this may be seen in odd body language, tone of voice or poor eye contact. People with ASD may take things too literally, miss the point of what others say in conversation or embark on monologues about their own interests. Real, reciprocal friendships and relationships can be hard for people with ASD to forge.

To explore social behaviours, experts may ask people whether they enjoy chit-chat or whether they find it easy to know what others are thinking. Children could be asked if they find it easy to play make-believe with other children. None of these responses on their own reveal if someone has ASD, but by asking many such questions, experts are able to build a picture of how an individual interacts with others.

Non social behaviours

People with ASD tend to dislike change and to show strong preferences for precise routines. They may engage in repetitive behaviour, talking or thinking, and have obsessive and narrow interests. They might have strong and unusual responses to specific sensations, such as certain sounds or smells.

Experts might ask someone if they plan activities carefully, if they often notice details that others do not and whether they enjoy doing things spontaneously. Of course, all of us differ in these traits. Those with ASD, however, may tend to answer in tell-tale ways.

An ASD diagnosis

A diagnosis of ASD will only be made if these social and non-social characteristics have been present since early childhood, and currently cause significant impairment.

3. CLICKABLE: Autistic spectrum

Click below to discover some of the factors taken into account by expert clinicians when they assess someone for ASD.

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Questionnaires designed to explore whether someone is autistic score people on a number of traits. Each trait is common, and most of us show at least a few. Scores fall on a spectrum across the population. Those who score a high number may receive a diagnosis of ASD.

4. Living with autism: Sarah's story

Autistic people can find social situations difficult. However, in the clip, Sarah shows she is an an accomplished public speaker able to talk in front of hundreds of people about the challenges of autism. She is able to do this because she can plan what to say, and everything is in her control. But she finds it much harder to speak to people for the first time, or in chance encounters.

One of her strategies for coping is to deliberately wake up about an hour before she needs to get up and run through what's likely to happen during the day. She imagines what types of people she might meet, and what conversations she might have with them. Sarah studies and imitates the way other people respond to each other in social situations. Despite this, she worries about failing to pick up on subtleties and does sometimes get it wrong.

5. What are the benefits of diagnosis?

There are many reasons why people might have difficulties in fitting in. For those diagnosed with ASD the knowledge may improve their lives.

Coping strategies

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Coping strategies

People with ASD can learn ways to cope with their difficulties in social situations. Learning about how others think can help them in their daily lives.

Helping others adapt

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Helping others adapt

If someone with ASD shares their diagnosis with friends and colleagues they can seek advice or training to help them understand ASD.

Secondary conditions

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Secondary conditions

It is common that additional problems, such as sleep problems, anxiety and depression accompany ASD. Many of these can be treated in their own right.


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A diagnosis of ASD can be helpful for some as an explanation of their long term struggles to fit in with others.