Autism in adults – signs and symptoms

Written and professionally reviewed by Felix Enghoff Klich, authorised psychologist
Last updated: September 2026

Autism can present very differently in adults. Some have clear challenges with social communication, sensory input and change, while others have for many years learned to adapt and hide their difficulties. Here we go through some of the most common signs of autism in adults – and when it may be relevant to consider an autism assessment.

Autism is an innate and lifelong neurodevelopmental condition. The core characteristics of autism concern social communication and interaction as well as more restricted or repetitive patterns of behaviour, interests and activities. In addition, many autistic people experience, among other things, different sensory processing and a strong need for predictability.

It is also important to remember that autism does not look the same from person to person. In some, the autistic traits become apparent early in life. In others, they only really become visible in adolescence or adulthood, for example when demands from social relationships, education, work or family life increase.

What are typical signs of autism in adults?

There is no single sign that in itself means a person has autism. Instead, one looks at an overall pattern that has been present since early development and continues to matter in adulthood. A professional assessment therefore covers current difficulties, the person's developmental history and functioning in, among other things, relationships, education, work and everyday life.

In adults, autistic traits can show in, among others, the following areas:

1. Social situations can take a lot of energy

Some adults with autism find that socialising does not feel intuitive. It may be necessary to actively think about what to say, when to speak, or how others expect you to react.

You may, for example, experience:

• uncertainty about unwritten social rules
• difficulty with small talk or knowing when to speak
• that irony, hints or indirect communication are hard to decode
• that you often analyse social situations before or after they have taken place
• difficulty making or keeping friendships
• a need for a lot of time alone after socialising.

This does not necessarily mean that you do not want social relationships. On the contrary, some want close relationships but find that navigating them takes considerably more energy.

When assessing possible autism in adults, NICE highlights persistent differences or difficulties in social interaction and social communication as central areas.

2. Communication can feel different

Autism can also show in the way you communicate. Some have very precise or direct language and prefer others to communicate clearly as well.

It can, for example, be hard to:

• understand what another person is hinting at without saying it directly
• read tone of voice, facial expressions or body language
• know how much information the other person needs
• switch between different ways of communicating depending on the situation
• judge when a conversation should end.

For others, these difficulties are very subtle. The person can appear socially capable but spend considerable mental resources continuously analysing the conversation.

3. Need for structure and predictability

Another possible characteristic is a strong need for structure, routines or predictability.

This can show, among other things, in that you:

• thrive best with clear plans and fixed routines
• prepare for activities very thoroughly
• are strained by sudden changes
• prefer to know in advance what will happen
• have particular ways of doing everyday activities
• feel unrest or stress when plans change.

It is not necessarily about every day having to be identical. For some, it is more that unpredictability requires extra mental energy.

Need for sameness, difficulty with change and rigid or repetitive patterns are among the central areas assessed diagnostically in autism.

4. Intense or highly focused interests

Many adults with autism have interests that they can immerse themselves in very intensely.

The interests can be very varied and do not have to be unusual. What stands out may rather be the intensity, level of detail or amount of time and energy spent on the interest.

For some, these interests are a significant strength. They can contribute to great expertise, perseverance, specialisation and joy. In other cases, it can be hard to shift focus or make room for other activities.

5. Different sensory experiences

Sensory differences are common in autism and are also part of a comprehensive professional assessment of adults.

This may, for example, be a particular sensitivity to:

• sounds
• light
• smells
• touch
• certain materials or textures
• temperature
• many simultaneous sensory impressions.

An ordinary office environment, public transport or a supermarket can therefore be far more draining for one person than for another.

Some experience the opposite and register certain sensory input less clearly. The sensory profile can therefore be very individual.

6. Overload and need for recovery

If you have to handle many social, sensory or unpredictable demands over a long period, you can become very strained.

Some adults describe, for example, a strong need to withdraw after work, social events or other situations with many impressions. Others experience periods when they find it harder to communicate, make decisions or handle further demands.

It is therefore relevant to look not only at what the person can do, but also at how many resources it takes to function in everyday life.

Autism can be less visible in adults

Autistic traits are not necessarily apparent to others.

Throughout life, some people develop strategies to adapt their behaviour to social expectations. This is often referred to as masking or camouflaging.

This may, for example, involve deliberately:

• imitating other people's body language or social behaviour
• preparing sentences and conversations in advance
• learning social rules systematically
• trying to maintain eye contact, even though it feels unnatural
• hiding the need for breaks or repetition
• suppressing behaviour that feels socially different.

This can mean that those around you do not immediately notice how demanding social situations are for you.

Can you have autism and still be social?

Yes. Being autistic does not mean that you cannot be social, have close relationships or be interested in other people.

Some autistic people are very social, while others prefer less social contact. What matters is not the amount of social contact alone, but among other things how social communication and interaction are experienced and function, and what pattern has been present throughout life.

It is therefore rarely meaningful to decide the question based on individual qualities such as eye contact, empathy, friends or the ability to hold a conversation.

Autism and ADHD can overlap

ADHD and autism are different neurodevelopmental conditions, but they can occur in the same person. NICE also highlights a history of ADHD as relevant information when possible autism in adults is assessed.

This can make the overall picture more complex. A person may, for example, need structure while at the same time finding it hard to create or maintain it themselves. Attention difficulties, impulsivity or inner restlessness can also affect how the autistic traits show.

Also read: AuDHD – living with both ADHD and autism →

Is it autism – or could the symptoms be due to something else?

Individual autistic traits are not the same as having autism.

Social insecurity, need for structure, sensory sensitivity or fatigue can also occur in people without autism. Some of the difficulties can also overlap with, among other things, ADHD, anxiety, OCD or other psychiatric issues.

An assessment should therefore not consist solely of a symptom list or a single screening test.

In a thorough autism assessment, the overall pattern is examined, including development from childhood, social communication and interaction, repetitive or rigid patterns, interests, sensory factors, everyday functioning and any other mental health or neurodevelopmental issues. NICE recommends that a comprehensive assessment looks at core traits, early developmental history, functioning and differential diagnostic factors.

Can an autism test tell me whether I have autism?

A self-screening can be a way of exploring whether you recognise a number of traits often seen in autism. However, it cannot in itself determine whether you have autism.

NICE describes, for example, the AQ-10 as a possible screening tool for adults without moderate or severe intellectual disability, but a screening result should be used to assess the need for a proper professional assessment – not as a diagnosis in itself.

Also read: sensory sensitivity in autism and psychoeducation for neurodivergence.

When can an autism assessment be relevant?

It may be relevant to consider an assessment if you have recognised several of the patterns above over a long period, and they affect, for example, your working life, education, relationships or well-being.

For some, the question of autism only makes sense in adulthood. This can happen, for example, after long periods of overload, after an ADHD assessment or when you start to recognise a lifelong pattern in your experiences.

An assessment is not only about examining whether the diagnostic criteria are met. It can also contribute to a more nuanced understanding of the person's individual strengths, challenges and needs. NICE similarly recommends that the assessment covers core traits, strengths and the person's functioning throughout life.

Autism assessment at Nordisk Psykiatri

At Nordisk Psykiatri we offer autism assessment of adults. The assessment is based on the individual and the overall clinical picture.

Frequently asked questions about autism in adults

What are the most common signs of autism in adults?

Signs can include persistent differences in social communication and interaction, a strong need for predictability, intense interests, repetitive patterns and different sensory experiences. How these traits show varies considerably from person to person.

Can you have autism without knowing it?

Some people are only assessed as adults. Autistic traits can be less visible, and the person may have developed strategies throughout life to navigate social and practical demands.

Can you make eye contact and still have autism?

Yes. Eye contact is only one aspect of non-verbal social communication. An autism diagnosis is not decided on the basis of eye contact alone, but on a broader and persistent pattern of traits and the person's developmental history.

Can you have both ADHD and autism?

Yes. ADHD and autism can occur together, and a thorough assessment should consider any other neurodevelopmental or psychiatric conditions.

Can an online autism test make the diagnosis?

No. A screening can point to traits that may make it relevant to examine autism further, but a diagnosis requires an overall professional assessment.

Sources

1. National Institute for Health and Care Excellence (NICE). Autism spectrum disorder in adults: diagnosis and management (CG142). 2012, last updated 2021.
   Particularly relevant for diagnostic characteristics, social communication, repetitive/rigid patterns, sensory differences and assessment.
   NICE – Autism spectrum disorder in adults
2. NHS. Signs of autism in adults.
   A good source for patient-friendly descriptions of social difficulties, routines, intense interests, sensory sensitivity and masking in adults.
   NHS – Signs of autism in adults
3. Centers for Disease Control and Prevention (CDC). Clinical Testing and Diagnosis for Autism Spectrum Disorder.
   Sets out the central diagnostic areas of DSM-5: persistent differences in social communication/interaction and restricted and repetitive patterns of behaviour, interests or activities.
   CDC – Clinical Testing and Diagnosis for Autism Spectrum Disorder
4. Pilling S, Baron-Cohen S, Megnin-Viggars O, Lee R, Taylor C, Guideline Development Group. Recognition, referral, diagnosis, and management of adults with autism: summary of NICE guidance. BMJ. 2012;344:e4082. doi:10.1136/bmj.e4082