Autism Symptoms: Core Signs and Traits

• OVERVIEW
• SYMPTOMS
• ADULTS
• CHILDREN
• WOMEN
• DIAGNOSIS
• TREATMENT
• MEDICATION

Autism symptoms vary from person to person, which is why it is often described as a spectrum, and the condition is also referred to as autism spectrum disorder (ASD). Some people may recognise these signs and traits early in life, while others may not identify them until adolescence or adulthood.

Understanding the common autism symptoms can help you make sense of long-standing patterns, challenges, and strengths. This guide draws on our clinical knowledge of autism and experience working with children and adults with ASD to provide you with clear information about autism traits, assessment, and support.

Key Takeaways

• Autism symptoms vary widely and may appear differently at various stages of life.
• Persistent patterns that affect daily functioning may indicate the need for an assessment.
• Autism assessments consider behaviours and development over time.
• Diagnosis can help guide appropriate support for children and adults alike.

Signs of Autism by Age Groups

Autism often begins in early childhood. However, some people with this condition may not know they have it and obtain their formal diagnosis when they are already adults.

Knowing the typical signs of ASD per age group can help you better understand how the condition may present at different stages of life.

0 to 12 Months

Babies who exhibit the following traits may have early signs of autism:

• Rarely smiling or responding to sounds and facial expressions
• Little to no eye contact
• Little to no babbling or cooing
• Discomfort with cuddling and other forms of physical contact
• Lack of interest in peekaboo and other back-and-forth games
• Intense sensitivity or reactions to certain sounds, bright lights, and other sensory stimuli
• Lack of appropriate reaction to some sensory stimuli, such as not removing their hand when touching hot water in the tub
• Rocking, flapping their hands, and exhibiting repetitive movements when stressed or bored

Children who do not respond to their name and do not engage in back-and-forth gestures, such as waving when they are 12 months old, are also likely to have autism. 

Some of these traits, such as the absence of babbling and cooing, can be considered autistic newborn signs.

1 to 2 Years

Autism early indicators in toddlers or kids between one and two include the following:

• Walking on their toes
• Limited or no speech or sudden loss of speech if the child was speaking before
• Difficulties in following simple instructions
• Displaying a strong interest in certain, usually unusual objects or ones that are typically unnoticeable and ignoring other things
• Engaging in repetitive behaviours and activities, such as lining up toys
• Hitting, biting, and displaying other physically aggressive behaviours when upset or overwhelmed
• Aversion to certain sensory experiences, such as hearing certain songs or not eating food of a particular colour   

2 to 5 Years

Toddlers and preschoolers who may have autism often display all the signs and symptoms mentioned above in addition to the ones below:

• Limited speech and echolalia or repeating words or phrases
• Little to no interest in pretend or imaginative play, and other children
• Intense interests, or fixations, on particular toys, objects, or activities, which can take up most of their time and attention
• Frequent tantrums and meltdowns
• Picky eating and possibly avoidant/restrictive food intake disorder (ARFID)

School-Aged Children and Adolescents

Older children and teenagers with ASD often display the autistic traits mentioned above, and these additional signs and symptoms:

• Difficulties building and sustaining friendships and other relationships
• Requiring time to recover or shutting down after being involved in social situations
• Difficulties in learning and often not wanting to go to school
• A need for clear rules and instructions, difficulties following implied guidelines or directions, and understanding other people’s perspectives  
• Problems with mental health, often experiencing anxiety, anger, burnout, and depression
• Being too direct, frank, and opinionated in social situations and taking things literally, which can cause misunderstanding
• Difficulties waiting for their turn during social interactions
• Following the same routine every day and getting anxious if it changes

This child autism checklist offers more signs and symptoms to look out for in each age group. But for a clearer perspective and to access the right support, proper assessment for children is important.

Adults with autism often retain traits and symptoms from childhood and adolescence. They may also develop new challenges, such as struggling to express emotions, forming new friendships, or preferring solitude over socialising.

How to Recognise Autism in Children and Adults

Recognising childhood autism often starts with noticing patterns in how your child communicates, interacts, and responds to the world around them. You may notice differences in social interaction, such as limited eye contact or a preference for playing alone.

Some children show strong reactions to noise, textures, or changes in routine, while others develop intense interests or repeat certain behaviours. These signs can appear early in childhood, but they do not look the same in every child.

If these traits feel persistent or affect daily life, the next step is to have your child assessed. A formal autism assessment for children looks at your little one’s behaviours and development over time.

A clinician will consider your child’s communication and social skills, sensory responses, and everyday functioning. An assessment can help you better understand their needs and guide appropriate support at home and at school.

The diagnosis will also confirm the level of autism, which ranges from level 1 (low support) to level 3 (substantial support).

Seeking an assessment is also important if you suspect you have autism yourself or another adult family member. An adult autism assessment can provide clarity, reassurance, and access to the right support at any age.

Adult women with autism, in particular, will benefit from a formal diagnosis as autistic signs in females are more subtle and not easily observable. They will be able to understand themselves better and seek appropriate support once they receive their assessment results.

Treatment Options

A clinician will recommend a customised treatment plan based on the diagnosis that answers the individual’s unique needs. The main goal is to reduce their symptoms and improve their learning and coping skills and independence.

Treatment and therapy options may include:

Behaviour and Communication Therapies

Applied behaviour analysis (ABA) and similar therapies aim to help children learn new skills and apply them appropriately to various situations.

Educational Therapies

Individualised, highly structured educational programs can help children and teenagers improve their learning, social, and communication skills, as well as their overall behaviour.

Supplemental Therapies

Speech and occupational therapies can improve the individual’s communication and self-help skills. Younger children who may have problems with movements and balance can benefit from physical therapy.

Medication

The specialist may recommend medications to help treat related symptoms, such as irritability, aggression, anxiety, and insomnia. For example, antipsychotic medicines may be prescribed to treat aggression and other severe behavioural autistic symptoms.

Frequently Asked Questions

Living with Autism 

Autism is a lifelong condition, but understanding and supporting the individual can make a meaningful difference.

Learning about the common autism attributes can reduce uncertainty and help guide the next steps, which include a formal assessment and following a treatment plan.

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