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Knowledge Base » Safeguarding » What is Autism Spectrum Disorder?

What is Autism Spectrum Disorder?

Last updated on 24th April 2023

Autism spectrum disorder, or ASD, is a neurological condition and developmental disorder. This condition primarily affects communication, learning and behaviour. It is possible to diagnose autism at any time, though it’s unlikely to be diagnosed before the age of two.

Diagnosticians often use a guide called the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) to help diagnose this disorder.

In simple terms, people with autism spectrum disorder will often demonstrate:

  • Difficulties in social interaction and communication.
  • Repetitive behaviours or restricted interests.
  • Difficulties with executive function and with work or school.

As its name suggests, there is a spectrum involved in ASD. This is due to the fact that people experience autism in different ways. Some people with ASD are non-verbal, for example, while others are more able to live easily and independently.

ASD affects all ethnicities, socio-economic backgrounds and genders. However, it is more often diagnosed in boys than girls. According to the World Health Organization, one in 160 people has an autism spectrum disorder. The UK National Autistic Society, however, suggests that 1% of people are on the autism spectrum. They also believe there to be around 700,000 people on the autism spectrum in the United Kingdom.

What are the different types of autism spectrum disorder?

Until very recently, there were considered to be lots of different types of autism spectrum disorders and people received different diagnoses as such. People were diagnosed with Asperger’s syndrome, autistic disorder, and PDD-NOS (pervasive developmental disorder not otherwise specified). This moved on to using labels like “high-functioning autism” and “low-functioning autism”, which many still use. Now, all of these are put under one umbrella as “autism spectrum disorders”.

Since many older people received their diagnosis with the terms above, it’s important that we understand what they all meant, even though they’re no longer used in new diagnoses.

Asperger’s Syndrome

Receiving a diagnosis of Asperger’s denoted “milder” symptoms of ASD. With Asperger’s a person could typically function well in daily life and they were often of higher intelligence. Due to their condition, people with an Asperger’s diagnosis would perhaps be highly focused on a special interest that they would talk about a lot. In terms of difficulties, there might be some social awkwardness or difficulties understanding social queues and norms.

Autistic Disorder

This is an older term that was diagnosed before Asperger’s. This diagnosis was given to those with more difficulties and to those who were not able to function independently without a lot of support.

PDD-NOS – Pervasive developmental disorder, not otherwise specified

This diagnosis was often given to children who were said to be autistic but who were not as severely affected. They were said to have more severe symptoms than someone with Asperger’s but didn’t warrant a diagnosis of autistic disorder.

What are the signs and symptoms of autism spectrum disorder?

With ASD being a spectrum, it presents in different ways for different people. Many autistic people don’t like the term “symptoms” to describe their problems and they reject this terminology.

These are some of the most common signs of autism according to the NHS:

Young children

  • Avoiding eye contact.
  • Not responding or reacting to their name being called.
  • Not reciprocating social cues like smiles.
  • Getting overly upset if they don’t like a particular sound, smell or taste.
  • Doing repetitive movements like hand-flapping.
  • Having delayed speech or no speech.
  • Repetition of the same words and phrases (echolalia).

Older children

  • Difficulties understanding others’ thoughts and feelings.
  • Difficulty communicating their feelings.
  • Enjoying a strict routine and being upset with changes to it.
  • Having a keen special interest in an activity or subject to a point of obsession.
  • Getting upset when asked to do something (demands being placed).
  • Preferring their own company and finding friendships hard to make or maintain.
  • Thinking literally – i.e., not understanding figurative speech like “he was on fire today”.
Young boy getting overly upset

Different signs in boys and girls

There is a notable difference in how many girls and boys are diagnosed as having an autism spectrum condition. A study also showed how the male-female ratio of 3:1 exists. This isn’t to say, however, that ASD is necessarily more prevalent in boys.

More and more diagnosticians are looking into how the condition presents differently in girls and women, and it is only very recently that the gender bias is being seriously called into question.

What seems to be happening with girls is that they are much better at “camouflaging” or “masking” their autistic behaviours. Girls and women who are intellectually able tend to be able to integrate better socially. However, this ability to construct social connections isn’t intuitive. Instead, they appear to learn behaviours by rote from watching others and imitating them. This “masking” means that ASD traits are less likely to be noticed by others.

What’s more, when it comes to special interests in female autistics, these are often the same as interests their peers might have like a boyband or horses. This means they won’t stand out or ring alarm bells. Also, the repetitive behaviours seen often in boys (like hand-flapping) aren’t as obvious in girls.

With all of this information, it’s likely that there are many undiagnosed girls and women, which would bring the ratio back to being more even.

What causes autism spectrum disorder?

Experts don’t really know what causes ASD. The condition was first observed and described during the 1940s but not much progress was made in terms of understanding it until recently. Even now, there is so much we don’t know about this spectrum of conditions.

There is a lot of research going into some possible contributors or causes of autism spectrum disorder.

Here are some key areas of research on the condition:


There is a lot of evidence supporting genes as being a contributory factor or a cause of ASD. However, over 100 genes of differing chromosomes could be involved and all to different degrees.

Lots of people who are diagnosed with autism have mutations in their genes but the link between these and ASD is complex. For example, many people who display signs of autism don’t have genetic mutations while many people without ASD do. What we understand so far is that different mutations probably have a role in ASD or increase a person’s likelihood of having the condition.

Environmental interactions with genes

If a person is susceptible to having ASD due to their genes, then certain environmental situations could cause that person to have autism. For example, chemical contact or an infection could cause autism in someone who is genetically susceptible.

Other factors at play

Scientists are also exploring other biological causes of ASD. These include brain connection problems, brain growth (problems with growth in particular areas or overgrowth), metabolic problems, and immune system problems.

What doesn’t cause autism?

While we’re discussing the causes of autism, it’s really important to point out some of the incorrect information that has been suggested over the years as a cause for autism.

Autism isn’t caused by:

  • The MMR (measles, mumps and rubella) vaccine. During the 1990s, an English doctor called Andrew Wakefield declared that the MMR vaccine had caused changes that led to autism in 12 patients. It was discovered that Dr Wakefield had a financial incentive to produce such results – he was developing his own vaccine that he wanted to monetise. Due to his dishonestly, Wakefield was struck off and his article was declared fabricated and dishonest.
  • Bad parenting. Many parents of children with an autism spectrum condition struggle to manage their child’s behaviour. Some 30 years ago, there was a theory that “refrigerator mothers” (i.e., mothers who were cold towards their children) caused autism in their children. Thankfully, this hurtful blaming is a thing of the past.

What are the risk factors of autism spectrum disorder?

Without knowing the true causes of autism spectrum disorder, it’s very difficult to talk about risk factors. However, there are a few things that increase the likelihood of a child being diagnosed with the condition.


From what we know so far, genes play an important role in ASD. This means that ASD runs in families. If you are a parent with an autistic spectrum condition, you’re more likely to have a child who is on the spectrum too. Similarly, if you have one child who is autistic, it’s more likely that subsequent children will have the condition.

Other risk factors

Other factors that increase a child’s risk of having autism include the age of the parents. When either parent is aged 35 or over, there is a higher incidence of ASD. This is only a very small percentage, however.

What’s more, when there are problems during pregnancy or birth, the risk of ASD could be higher.

This could include:

  • A baby being born early (especially if the child is very premature).
  • A baby being born breech or with another birth trauma.
  • A baby having a low birth weight.
  • A baby having a birth defect.
Premature baby at risk of an ASD condition

Other health problems

There are other health conditions that are comorbid with ASD.

These include:

  • Fragile X syndrome, Down syndrome, Rett syndrome, tuberous sclerosis, or other genetic disorders.
  • Developmental disorders like ADHD (attention deficit hyperactivity disorder).
  • Tic disorders like Tourette syndrome.
  • Epilepsy.
  • Gut problems like chronic diarrhoea or constipation, or gastroesophageal reflux.
  • Problems with the immune system.
  • Sleep problems.
  • Mental health conditions like anxiety, depression, psychotic disorders, personality disorders, substance/alcohol abuse disorders.

Having one of these conditions doesn’t mean you’re likely to be autistic. It’s simply more common in people with these conditions.

Diagnosing autism spectrum disorder

For many people, getting an autism diagnosis is important. There are different pathways to diagnosis depending on age and also your area. For children under five, the first port of call is usually a health visitor.

For children over the age of five and for adults seeking a diagnosis, it’s best to visit the GP. For school-age children, the school SENDCO (special educational needs and disability coordinator) can help too.

Depending on the Trust, GPs refer people for autism assessments in different ways. Some NHS trusts refer children to CAMHS (Children and Adolescent Mental Health Service) even though autism isn’t a mental health condition. For other trusts, the referral goes to specialist paediatricians who then decide if the signs warrant being put on the autism diagnostic pathway.

Unfortunately, assessment waiting lists are extremely long and many people wait years before having an assessment and getting their diagnosis.

What happens at an autism assessment?

In a children’s assessment, you might be seen by a team of individuals with different specialities. This might be a clinical psychologist, a speech and language specialist, and a social and communication specialist. The team usually asks parents about their children’s development from birth, including when they met their milestones.

They will also watch how the child plays and interacts with others. A part of the diagnostic process usually involves reading reports by other medical professionals involved in the child’s care as well as reports from their school, including Education and Health Care Plans (EHCPs), if the child has one.

For adults, the assessment is somewhat easier and is a matter of filling in questionnaires and reading reports from medical professionals. The team might also talk to people who knew the adult as a child to find out about their development.

Finding out the results of an autism assessment

After being assessed, there will be a report produced of the findings. This might be given to you in person at an appointment or sent through the post.

The report will say whether or not a diagnosis for autism spectrum disorder has been given. It might also detail the sorts of things that the person might need help with including communication, interaction, hypersensitivity to smells, sounds, colours, or lights, and certain behaviours.

Treatments and therapies for autism spectrum disorder

Autism is a life-long condition and there is no cure for it. That said, there are ways to support people who have autism to make their life easier and more manageable.

ABA – Applied Behaviour Analysis

There is a controversial therapy called Applied Behaviour Analysis, or ABA. This is used by many parents who wish to teach their children to behave more typically. It was developed during the 1980s by a behaviouralist called Dr Lovass who believed autistic traits could be suppressed. For example, autistic children would be taught how to change their supposed “socially unacceptable” behaviours like stimming to more acceptable ones.

The controversial side to this treatment, however, is that many autistic people who have gone through it do not agree with it. Essentially, many feel that they have been forced to become “normal” simply to please others and wider society.

Therapies that can help

One common therapy that is typically used to help autistics (and one that is less controversial) is speech and language therapy. For some people with ASD, speech therapy teaches them to speak, while others learn other ways of communicating like Makaton.

Since many people with an ASD condition have sensory needs, providing sensory therapy and sensory toys can really help calm them. By providing opportunities for sensory needs to be met, children with ASD can really thrive in situations they’d otherwise find difficult.

Man with an ASD condition taking part in sensory activities

What support is available?

With autism being diagnosed more often, there is much more support available nowadays than in the past, both in terms of support for the person who is autistic as well as their family. Support is available in many forms.

Here are some examples of the type of support you might have access to:

Support in school

For children with an autism spectrum condition, the SENDCO is the best person to contact for support. Depending on the child’s individual needs and difficulties, an Individual Education Plan (IEP) might need to be put into place.

If the child’s needs are severe, they might need an Education and Health Care Plan, otherwise known as an EHCP. Only around 1% of children attending mainstream schools have EHCPs, but you must have one to access specialist provision. Either the school or the parent can apply for an EHCP needs assessment. An EHCP is entirely needs-based, and a diagnosis is not needed.

If a child doesn’t need an EHCP, their name should still be included on the Special Educational Needs register at the school due to their diagnosis or difficulties.

Support – financial

For children who have difficulties above and beyond typical children their age, financial support is available for parents in the form of Disability Living Allowance (DLA). There are two parts to DLA – a care component and a mobility component. To receive the lower-rate care component, parents must be provided over one-hour extra care per day for their child when compared to a typical child of the same age.

There is also a medium rate and high rate for children with greater needs. It is possible for autistic children to receive the lower-rate mobility component too, especially if they are not road safe. The Cerebra website can help with applying for DLA for autistic children.

Support through the council

Many local councils offer parenting classes free of charge to parents of autistic children or children who are waiting to be assessed. These also provide opportunities to meet other parents in a similar position.

Support through charities

Charities are also great at supporting parents, children and their families. Depending on where you live, local autism charities often put on events for autistic children and their families. Many also provide sibling activities too for those children affected by their sibling’s diagnosis.

Final thoughts

When talking about autism and finding out about it, it’s important to seek information and advice from people who are actually autistic. There are lots of debates around terminology with questions asked like: should you say, “has autism” or “is autistic”? In reality, no two people – autistic or otherwise – will agree.

It’s important, however, that people diagnosed with an autistic spectrum condition feel validated and listened to. If they wish to be referred to as “autistic” rather than being described as “having autism”, that’s their right. A common phrase that is mentioned frequently in the autistic community is that when you’ve met one autistic person, you’ve met one autistic person, such is the diversity of the autistic spectrum.

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About the author

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Louise Woffindin

Louise is a writer and translator from Sheffield. Before turning to writing, she worked as a secondary school language teacher. Outside of work, she is a keen runner and also enjoys reading and walking her dog Chaos.

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