Signs of autism spectrum disorder include differences in communication and behavioral patterns. But not all autistic folx behave or communicate in the same ways.

For some autistic people, it can feel as if there’s a communication gap between you and allistic (nonautistic) people.

The differences that come with being autistic can bring both unique benefits and challenges.

For example, some autistic people find their ability to hyperfocus allows them to power through work, but small changes in the daily routine impact them much more than they may other people.

Autism symptoms exist on a spectrum, which is why the condition is currently called autism spectrum disorder (ASD), and a reason the causes of autism aren’t well established yet.

Language matters

When it comes to talking about autism, we use identity-first language rather than person-first language. This is why we say “autistic person” rather than “person with autism.”

For many autistic people, this language is preferable because autism is seen as as part of an identity, not a disability.

While autism spectrum disorder is most often diagnosed in childhood, some presentations of autism may not be diagnosed until adulthood.

Autistic adults who are “high functioning,” or who have less noticeable communication and behavioral differences, may experience symptoms like:

  • anxiety in new or unstructured situations
  • difficulty decoding what makes sense to say in conversations
  • stiff or exaggerated body language or hand gestures
  • the wish to make friends but lack understanding of how to do it

Autistic adults may camouflage their repetitive behaviors when around other people. Suppressing these behaviors, which can be soothing, may lead to autistic burnout for some people.

Do you think you’re autistic but aren’t sure? This autism quiz may help.

The Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR) places autism symptoms into two main categories:

  • patterns of communication and social interaction
  • patterns in behavior and interests

Since autism is a neurodevelopmental disorder, the first signs tend to appear in early childhood and infancy. Still, some autistic people don’t get a diagnosis until adulthood, especially if they’ve gotten used to masking their differences.

Communication patterns

Autistic people may show different patterns of communication. These patterns may involve verbal or spoken communication and nonverbal communication like facial expressions and body language.

These communication-related autism symptoms impact:

  • social skills and interaction
  • nonverbal communication
  • relationships and social connection

Social skills and interaction

Hand gestures during a conversation and figures of speech can be hard to decode for some autistic people. Still, these communication differences can show up differently from person to person.

For autistic people who need higher levels of support, it can be harder to initiate or respond to social interaction.

While many autistic people speak in full sentences, other people might be nonverbal — meaning they tend not to speak out loud — and communicate in other ways.

Nonverbal communication

Nonverbal communication is how people communicate with each other without words. Some autistic people tend to engage in nonverbal communication differently than nonautistic people.

Autistic people might have difficulty with:

  • eye contact
  • decoding facial expressions or hand gestures
  • expressing their thoughts and feelings
  • matching the facial expressions of behaviors of other people

Relationships and social connection

Autistic folx may find it difficult to connect emotionally with other people, especially nonautistic people.

Difficulties adjusting speech and behavior to match the mood of a conversation might make it harder for some autistic people to start or maintain a relationship, for example.

In autistic children, this can look like not participating in games that involve imagination. Autistic children may also show a lack of interest in making friends, although this is not the case for all autistic people.

Behavioral patterns

Other autism symptoms involve behavioral differences. These differences usually include limited and repetitive behaviors.

These symptoms may include:

  • stereotyped behaviors (repetitive behavioral patterns)
  • rigid routines and dislike of change
  • “narrowed,” or strong and specific focus
  • differences in responses to surroundings

Stereotyped behaviors

Stereotyped behaviors are behaviors that are repeated over and over but don’t seem to have a clear purpose.

Still, these behaviors do have a purpose. They’re usually a form of self-soothing, also known as stimming.

These behaviors can involve:

  • hand flapping
  • finger flicking
  • coin spinning
  • lining up objects
  • other repeated actions

Autistic people might also tend to repeat the speech of other people. This is called echolalia.

Rigid routines and preference for structure

If you’re autistic, you might feel strongly about certain daily routines, habits, or rules.

Changes to these things can also be difficult. A change that seems insignificant to someone else might feel like a big impact for you.

For example, you might have a specific walking route or always eat a certain brand of cereal. If someone tries to change these routines or something happens that makes them impossible, it can bring feelings of instability, feeling lost, or not knowing what to do next.

Narrowed focus, interests, and preoccupations

Autistic people may have a strong focus or “narrow” interest in certain topics or subjects.

For example, an autistic child might prefer to play with a single toy over all other objects. An autistic adult might have an area of interest in a specific topic that they know a lot about.

Hyperfocus on certain activities and restrictive food intake are also common.

Responses to stimuli in the environment

Over- or under-sensitivity to stimuli in the environment is another common behavioral symptom of autism.

  • Someone with hypersensitivity may react in a way that seems out of proportion to a situation. For instance, an autistic person might cover their ears in a room where multiple people are talking at once.
  • An autistic person with hyposensitivity might react less strongly to stimulation or sensations. They might not react to pain or changes in temperature, for example.

Some autistic people may also be drawn to certain sensory experiences, including:

  • textures
  • smells
  • tastes
  • sights
  • sounds

For example, while one person might repetitively smell or touch an object, another person might fixate on objects of a certain color or texture.

Since autism exists on a spectrum, the level of support needed in day-to-day life varies greatly from autistic person to person.

The DSM-5-TR looks at three levels of needs, which are defined by how much support an autistic person may require.

  1. Requires support. Autistic people at this level may be more independent. Challenges with social interaction, change, or uncertainty may still be hard to manage without some level of support.
  2. Requires substantial support. Some social interaction and change may be manageable for autistic people at this level, but a consistent level of support is necessary.
  3. Requires very substantial support. People in this category may have minimal speech and social interaction. Handling change may be a significant challenge.

Outdated diagnoses

Some diagnoses previously tied to autism spectrum disorder are now outdated and seen as part of the autism spectrum. Some autistic people still identify with these diagnoses, though.

Some of these labels include:

Every autistic person is unique. An autistic person won’t always fit exactly into one of these levels or categories, and there’s no list of symptoms of autism that applies to everyone. For instance, some autistic people may be nonverbal but need only minimal support in day-to-day life.

In most situations, symptoms of autism are diagnosed during childhood. Parents may notice behavioral differences in their child and consult a doctor for more information.

After watching the child’s communication and behavior, the clinician may be able to help determine whether they meet the symptom criteria for autism. Your health professional might also refer you to a specialist who is skilled at recognizing autism in children.

According to the DSM-5, you might meet the criteria for an autism diagnosis if your communication and behavioral patterns:

  • impact multiple areas of your life
  • have been present since your early childhood
  • make areas of your life, like work or relationships, harder to manage
  • aren’t better explained by an intellectual disability

A clinician who’s diagnosing autism will also note whether symptoms are accompanied by intellectual and/or language impairment or catatonia.

If you’re an adult and think you might be autistic, it can be difficult to find a specialist who knows how to diagnose autism in adults. While this can be a challenge, it’s not impossible.

If you’re autistic, you’ll likely show certain patterns of behavior and communication. And while some autistic people need a lot of day-to-day support, others need only a little.

Many autistic people lead happy, full lives. For some autistic people, behavioral patterns make day-to-day living harder or negatively impact their mental health. If this sounds like you, learning ways to manage these patterns can help.

You can learn more about strategies for managing as an autistic adult here and get tips for supporting autistic children here.