What Is Adult Autism?

Adult autism simply refers to autism that is identified or diagnosed later in life. Clinicians describe autism as a neurodevelopmental condition - meaning it is present from birth and continues throughout life. Dr Alison Lennox describes autism as a divergent neurotype, reflecting natural differences in how people experience and interact with the world.

While every autistic person is unique, shared characteristics often include differences in social communication, perception, and behaviour. Autism is not a mental illness, though autistic individuals may experience co-occurring mental health needs such as anxiety, depression, or burnout.

The term autism is preferred by most autistic individuals today. However, diagnostic manuals often use Autism Spectrum Disorder (ASD), and some prefer Autism Spectrum Condition (ASC) to avoid the word “disorder.” In the past, terms like Asperger Syndrome and High-Functioning Autism were used. You are always encouraged to use the language that feels most comfortable for you.

How Common Is Autism?

Autism is estimated to affect around 1 in 100 people, making it a relatively common neurotype. It occurs in all genders, though it is still diagnosed more frequently in males. There is growing recognition that autistic women and non-binary people may present differently or mask their traits, highlighting the need for greater awareness and nuanced understanding.

What Are the Signs of Adult Autism?

Signs or traits of autism in adults can vary widely. Common experiences may include:

• Differences in navigating conversations

• Difficulty identifying or describing feelings (alexithymia)

• Preference for literal or direct language

• Using learned or “scripted” phrases in social situations

• Differences in eye contact, gestures, or facial expression

• Masking behaviours to fit in, often leading to exhaustion or burnout

• Unique experiences in friendships and relationships

• Engaging in stimming movements (e.g., rocking, spinning, tip-toeing, or flapping)

• Distress when faced with unexpected changes

• Strong preference for routines, order, or rituals

• Specific rules or sensitivities around food and eating

• Deep focus on particular interests or passions

• Sensory sensitivities (e.g., loud noises, bright lights, certain textures, or temperature changes)

How Is Adult Autism Diagnosed?

An adult autism diagnosis is made by a qualified and experienced clinician - usually a psychiatrist or psychologist - following a detailed in-person assessment. There is no single medical test for autism. Instead, clinicians may use structured diagnostic tools such as the Autism Diagnostic Observation Schedule (ADOS), to support their clinical judgment.

The process typically involves:

• A thorough clinical interview to explore your life experiences

• Comparison with official criteria (DSM-5 or ICD-11)

• Gathering collateral information, where possible, from people who know you well

Possible outcomes include:

• A formal diagnosis of autism

• Identification of some autistic traits without meeting full criteria

• Recognition of another explanation for your differences

A high-quality assessment should be neuroaffirmative - acknowledging your strengths, respecting your communication preferences, and offering adjustments to ensure comfort and inclusion throughout the process.

Is It Worth Having an Adult Autism Assessment?

For many people, an autism assessment in adulthood brings clarity and validation. A formal diagnosis can:

• Provide a stronger sense of identity and self-understanding

• Improve self-esteem and relationships

• Help access appropriate support, accommodations, or workplace adjustments under the Equality Act 2010 and Autism Act 2009

• Guide healthcare professionals to better address your mental and physical health needs

• Offer language to communicate your experiences more effectively with others

Many describe the process as empowering, enabling them to better understand their strengths, challenges, and how they interact with the world.