What Are the DSM-5 Diagnostic Criteria for Autism?

This guide explains the autism diagnostic criteria in plain language, including what clinicians look for, why early development and daily impact matter, what support levels are, and how ICD-11 differs.

The DSM-5 is the Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association. The ICD-11 is the International Classification of Diseases, published by the World Health Organization.

In the UK, NICE guidelines say autism should be diagnosed using either one. They're very similar, and most specialists draw on both.

Since 2013, the DSM-5 has used a single diagnosis of autism spectrum disorder. This replaced older terms, such as Asperger's syndrome. Many people now simply say "autism" or "autistic".

The DSM-5 describes three types of difference in social communication and interaction. For a diagnosis, all three need to be present, now or in the past:

• Back-and-forth social interaction: for example, finding conversation hard to start or keep going, sharing interests or feelings differently, or responding to others in unexpected ways
• Non-verbal communication: for example, differences in eye contact, facial expressions, gestures or tone of voice, or finding other people's body language hard to read
• Relationships: for example, finding it hard to make or keep friends, adjust to different social situations, or join in with imaginative play

These differences need to show up across different settings, not just in one place or with one person.

The DSM-5 describes four types of restricted or repetitive behaviour. For a diagnosis, at least two need to be present, now or in the past:

• Repetitive movements, speech or use of objects: for example, rocking, hand-flapping, lining things up, or repeating words or phrases
• Strong need for sameness or routine: for example, distress at small changes, rigid thinking, or needing to follow the same routines
• Intense, focused interests: interests that are unusually strong or specific
• Sensory differences: being over- or under-sensitive to things like sound, light, touch, smell, taste, pain or temperature, or seeking out certain sensations

Many autistic people describe these as important parts of who they are. Routines can bring comfort and predictability, and intense interests can bring joy and expertise.

Signs need to have been present in early development. But they may not become fully clear until later in life, when social demands increase. They can also be hidden by strategies the person has learned, often called masking.

This is why many people, especially women and girls, aren't diagnosed until adulthood. A developmental history, such as an ADI-R interview, helps clinicians understand what early childhood was like.

The differences need to cause significant difficulties in important areas of life, such as school, work, relationships or looking after yourself.

Some people manage on the surface, but only by putting in huge effort, which can lead to exhaustion or burnout. A good assessment looks at the effort behind how things appear, not just the outcome.

Clinicians also consider whether something else better explains the differences, such as a learning disability, a language disorder, anxiety, trauma or ADHD.

Autism can also occur alongside these conditions. A careful assessment makes sure everything that's going on is recognised.

The DSM-5 also describes three support levels, based on how much support someone needs in each of the two areas:

• Level 1: requiring support
• Level 2: requiring substantial support
• Level 3: requiring very substantial support

Support levels describe needs at a particular time, and can change. They aren't fixed labels, and don't describe someone's abilities or worth. Not every UK clinician includes them in a report, as the focus is often on describing individual needs instead.

The DSM-5 may also note whether someone has a learning disability, language difficulties, or another related medical or genetic condition.

ICD-11 describes autism in a very similar way, with the same two main areas. The main differences are:

• No set number of signs: ICD-11 describes typical features, rather than requiring a specific number in each area
• No support levels: instead, it describes whether someone also has a learning disability, and how much they use functional language
• Clearer recognition of masking: it notes that some people may manage well in some situations through exceptional effort, which may hide their difficulties

Both lead to the same diagnosis: autism.

Raiys works nationwide, offering online autism assessments carried out by an experienced, specialist team. We use DSM-5 and ICD-11 criteria and follow NICE guidelines, bringing together questionnaires, a developmental history and an ADOS-informed observation or the Autism Clinical Interview for Adults (ACIA).

You'll receive a clear, detailed report you can share with your GP, school or employer.

You'll also have access to the Raiys app, where you can securely read your report and use BeChange, our digital support programme. BeChange helps you understand your diagnosis and build practical, everyday strategies at your own pace, with resources across five areas: Mind, Resilience, Life, Move Matters and Nutrition.

If you're in crisis right now, call 999, go to A&E, or call Samaritans free on 116 123, any time of day or night.

Ready to take the next step? Find out more about our autism assessments.

The criteria can look like a checklist, but a good assessment is never just about ticking boxes. It's about understanding the person behind them, including their strengths.