Autism symptoms: the core signs and traits

Many people look up the signs of autism after years of feeling a little out of step with everyone around them. For others, a moment with a child or a partner suddenly made something click. Reading a list like this can stir up a lot, and you can take it at your own pace. AuDHD Psychiatry sees the signs below as ways of thinking and connecting that differ, not as faults in a person.

What are the core signs of autism?

The signs of autism come down to two core areas. The first is social communication and interaction, meaning how someone talks, listens and relates to other people. The second covers repetitive behaviours, routines and focused interests, and sensory differences sit inside it [2]. Autistic people often call those behaviours self-soothing or self-regulating, and describe their interests as focused and dedicated [2]. Seen that way, a routine or a deep interest is often doing a real job for the person.

Clinicians draw on two manuals, the DSM-5 and the ICD-11, which both describe these characteristics [2]. Clinicians in the UK use one of them to make a diagnosis [2]. Our guide to how an autism diagnosis is made covers the steps. Autism isn’t a line running from “more” to “less” autistic. Each autistic person has a unique mix of characteristics, strengths and challenges [1]. You’ll also see the medical name, autism spectrum disorder (ASD), on NHS pages [5]. For the condition as a whole, rather than how it shows, read what autism is.

Signs in social communication and interaction

The social side tends to show in conversation, friendships and reading other people. Everyday examples from the lists for adults and for children include [3][4]:

• finding it hard to talk to other people, or to read facial expressions, gestures and tone of voice.
• taking things literally, so “it’s a piece of cake” sounds like it’s about cake, or sarcasm gets missed.
• using eye contact less often, with fewer facial expressions and gestures.
• talking at length about an interest without stopping to listen or respond.
• speaking in a flat tone, or one that sounds different from what people expect.
• spending more time alone, or having few close friends.

Each of these is about how two people meet in the middle, not a lack of caring. A conversation can take real effort when tone and expression don’t come through clearly, and others rarely see that effort.

Repetitive behaviours, routines and focused interests

The second area covers routines, repeated actions and deep interests. In daily life, that can look like this [3][4]:

• having fixed ways of doing things, and getting distressed when a routine changes.
• finding big changes hard, such as moving from primary to secondary school.
• needing rules to be followed, and getting upset when someone breaks them.
• repetitive movements, known as stimming, such as rocking, flapping hands or flicking fingers.
• repeating words or phrases.
• being very focused on particular topics, which many autistic people call special interests.

Together, these make up what the manuals call restricted and repetitive behaviours and interests [1]. Those are clinical words, but the things they describe are often a source of comfort, calm or real enjoyment.

Sensory differences

Sensory differences are part of autism, and they can work in both directions. Someone can be very sensitive to one input, barely notice another, and react differently in different places [1]. Examples on the list for children include [4]:

• disliking bright or noisy rooms.
• disliking certain clothes or materials.
• eating only certain foods or textures.
• seeking out calming sensations, such as movement, pressure or sounds.
• finding it hard to describe feelings such as hunger or pain.

Sensory traits don’t count as an area of their own. In a diagnosis, they sit within the repetitive behaviours and interests, because of the avoiding, seeking or distress they can cause [1]. Our guide to sensory processing differences looks at how the senses can work differently.

Why some signs show early and others only later

Autism can be noticed at a very young age, or not until later in life [4]. Across the world, the first traits often appear in early childhood while a diagnosis comes much later [8]. That’s why so many people only start asking questions as adults. In older children, coping strategies or a supportive setting can mask these traits [7]. Sometimes nobody has noticed them, the child included [7].

In young children, speaking later or not responding to their name can be early clues [4]. Our guide to early signs of autism in children follows them by age.

Adults often adjust how they come across, which can make their traits harder to see [3]. Our guides cover signs of autism in adults, autistic masking and signs of autism in women.

What else can look like autism, or sit alongside it?

Several other conditions can look like autism, or occur alongside it. Autism can be harder to spot when someone also has ADHD, anxiety, depression, an eating disorder or a learning disability [3][4]. ADHD is more common in autistic people [5]. Our page on how ADHD and autism differ sets the two side by side.

Autistic people are also more likely to have some physical and mental health conditions, such as epilepsy, anxiety or depression [5]. Having one of these doesn’t rule autism in or out. Some autistic people have a learning disability, while others have average or above-average intelligence [5]. A specialist looks at someone’s whole life, from early childhood to now, before reaching a view.

What to do if these signs sound familiar

An assessment can help when social difficulties or rigid routines last and hold back work, study or relationships [6].

An assessment may help if:

• these traits go back to childhood.
• they cause problems at work, home or in relationships.
• you’ve long wondered whether you’re autistic, or have ADHD too.

It might not be right today if:

• you need urgent help now. Call NHS 111 and choose the mental health option, or in Northern Ireland call Lifeline free on 0808 808 8000, any time. In an emergency, call 999 or go to A&E [9].
• you’re asking about a child. The autism assessment for children at AuDHD Psychiatry covers ages 6 to 17, and a parent can be present.

Our adult autism assessment is two online appointments: the assessment, and an interview with someone who knows you well. We can still assess you if there’s no one who can take part. An assessment for ADHD and autism together takes three. Start with the free autism test, a screen rather than a diagnosis, or a free 15-minute call.

Questions people ask

In short

Autism shows up in two broad areas: how a person communicates and connects, and their routines, repeated actions and interests. Sensory differences belong to that second area. No two autistic people share exactly the same mix, and plenty reach adulthood before anyone puts a name to theirs. A list of traits can raise the question, but it can’t answer it. If the pattern feels familiar, AuDHD Psychiatry can help you work out what to do next.