Q

At What Age is Autism Diagnosed?

Wondering when autism is typically diagnosed and how professionals determine if a child is on the spectrum? Early identification is key, but the timeline can vary. This guide breaks down when autism is usually diagnosed, the signs to look for, and how to navigate the process, helping families understand what to expect.

A

Answered by

Encore Support Staff

Autism is often detectable in early childhood, with signs emerging as early as six months and a reliable diagnosis possible by age two. But every child is different, and some traits may not become obvious until later. Understanding the early indicators—like differences in social engagement, communication, or behavior—can help families seek the right support at the right time.

Whether you’re wondering about early signs, diagnosis timelines, or what steps to take next, this guide will walk you through the essentials of autism diagnosis and early intervention.

How Early Can Autism Be Diagnosed?

Autism can be diagnosed as early as 18 months, with some children showing early signs within the first 12 months of life. However, signs may not become apparent until 24 months or later in some cases.

Pediatricians and specialists use developmental milestones, parent-reported concerns, and clinical observations to assess early signs of autism. While some children receive a diagnosis before age two, others may not be identified until preschool or even later if symptoms are more subtle or if access to screening is limited.

Can Autism Be Detected Before Birth?

While there are no definitive tests for autism during pregnancy, research has explored potential signs of autism in utero. Some studies suggest that certain behaviors or developmental markers might be observed through ultrasound, but these are not diagnostic tools. For example, reduced fetal movements or differences in brain development might be noted, but these are not conclusive indicators of autism.

At What Age Can Autism Be Reliably Diagnosed?

The American Academy of Pediatrics (AAP) recommends autism-specific screening at 18 and 24 months, in addition to developmental screenings at 9, 18, and 30 months. By age 2, an experienced professional can provide a reliable autism diagnosis.

While some children may receive a formal diagnosis before their second birthday, others—particularly those with milder symptoms—may not be diagnosed until later. Early screening and monitoring are essential to ensuring that children receive support and intervention as soon as possible.

When Do Children Usually Show Symptoms of Autism?

Autism symptoms can appear as early as six months, though they may be subtle at first. Early signs often involve differences in social interaction, communication, and behavior. Some of the earliest indicators may include limited eye contact, a lack of social smiles, and reduced interest in people.

By nine months, some children may show little or no back-and-forth engagement, such as cooing, smiling, or gesturing.

By one year, a child with autism may not respond to their name, babble, or use gestures like waving. Since symptoms vary widely, pediatricians rely on developmental screenings to track progress and identify potential concerns.

Symptoms of Autism in Newborns

Newborns typically do not show clear signs of autism, but some early indicators may include:

• Limited or no response to their name by 12 months
• Little or no babbling by 12 months
• Very few or no words by 16 months

Signs of Autism in Toddlers

As children grow, autism symptoms may become more pronounced. In toddlers, signs may include:

• Limited speech or language delays
• Difficulty in following simple verbal instructions
• Repetitive behaviors like hand flapping or rocking
• Intense interest in certain objects or activities

Signs of Autism in Teens & Adults

Autism symptoms can persist into adolescence and adulthood, though they may manifest differently as individuals develop coping strategies. Common signs include:

• Difficulty with social interactions and relationships
• Challenges in understanding social cues or nonverbal communication
• Repetitive behaviors or routines
• Sensory sensitivities

When is an Autism Diagnosis Considered Late?

A diagnosis is considered late if it occurs after the age of three. Many children are diagnosed around preschool age when social and communication challenges become more noticeable. However, some individuals, particularly those with milder symptoms or high-masking abilities, may not receive a diagnosis until adolescence or adulthood. Early screening and awareness can help ensure children receive support as soon as possible.

Can Autism Develop Later in Life?

Autism is a neurodevelopmental condition present from birth. It does not develop later in life, but some individuals may not receive a diagnosis until adulthood due to the subtleness of their symptoms or a lack of awareness.

Many people with autism, particularly those with less pronounced traits, adapt or “mask” their symptoms to blend in socially, which can delay recognition and diagnosis. As awareness grows, more adults are being diagnosed and connecting with resources that help them navigate work, relationships, and daily life.

Who is Qualified to Diagnose Autism?

A formal autism diagnosis should be made by qualified professionals who specialize in developmental and neurological conditions. These may include:

• Developmental pediatricians
• Child neurologists
• Child psychologists or psychiatrists
• Multidisciplinary teams with expertise in autism

What to Do After Autism Diagnosis

Receiving an autism diagnosis can be overwhelming, but it is also a crucial step in accessing support and resources. Here’s what families and individuals can do next:

• Seek Early Intervention: Early intervention services can significantly improve outcomes.
• Educate Yourself: Learn about autism, its spectrum, and available therapies.
• Connect with Support Groups: Find support from communities or organizations like Autism Speaks or AutismSA.
• Plan for the Future: Consider educational plans, therapies, and long-term support strategies.

Early or Late Diagnosis? We’re Here to Help

Whether your child receives an early or late diagnosis, understanding the signs and seeking professional help is crucial. Early detection and intervention can lead to better outcomes, but support is available at any stage of life. Remember, every child with autism is unique, and tailored interventions can make a significant difference.

At Encore, we provide individualized, evidence-based autism therapy to help children develop essential skills and thrive. Whether you’re exploring early signs, seeking a diagnosis, or navigating the next steps, we’re here to help.

Contact us today to learn more about our personalized therapy options and how we can support your family’s journey.