How soon can a child be diagnosed with autism?

Children may be diagnosed with autism by age two, but a more definite diagnosis may come several years later. 

The American Academy of Pediatrics recommends all children be screened for autism between 18 and 24 months to possibly benefit from the option of early intervention therapies, like ABA therapy. 

Autism spectrum disorder (ASD) may be diagnosed at an early age, about 14 to 16 months, though many parents do not receive a definite diagnosis till much later. Parents may notice atypical behaviors or developmental delays just a few months into a child's life. However, many children are not diagnosed until they present more obvious symptoms around the age of two years old or older.

A study published in 2019 found that it was possible to diagnose autism as early as one year into a child's life. However, this diagnosis was more likely to be overturned compared to one made around 14 to 18 months of age. The earlier intervention is applied to the child in question, the more positive outcomes come to pass.

Pay close attention to your child's behaviors and development, even in infancy. While some signs of autism can be unclear, presenting several signs at once should prompt parents to seek a diagnosis as early as possible. Some early signs may include no interest in playing pretend, delayed speech and language skills, and/or quick upset to routine changes.

Most Parents and Caregivers Overlook Autism Until After Age Three

Even though the American Academy of Pediatrics recommends universal screening for autism around age two, how soon a child can be diagnosed with autism varies as many children aren’t diagnosed until they are more than three years old.

The National Institute of Child Health and Human Development states, "Research shows that early detection and early intervention greatly improve outcomes. So it's important to look for these symptoms when a child is as young as possible."

Earlier studies have shown that delayed diagnosis can be correlated with a number of common factors. Using the older classification system before the DSM-5 revision, children with "autistic disorder" had an average age of 3.1 years at their time of diagnosis, which increased to 3.9 years for a diagnosis of "developmental disorder not otherwise specified" (PDD-NOS). 

In the past, children with Asperger's disorder were diagnosed at an average age of 7.2 years. These findings indicate that children with more pervasive symptoms or who struggled with verbal communication were more likely to receive a diagnosis at a younger age due to parents recognizing their struggles more obviously versus their child having “quirks” or just assuming symptoms were a result of their personality.

Other correlative factors with an older age of diagnosis include living in a rural community, being near the poverty level, or having four or more primary care physicians.

How pervasively the ASD presents is the single largest factor in how soon a child can be diagnosed with autism, though. A 2013 study found that children with just seven of the 12 main behavior features were diagnosed at an average age of 8.2 years, whereas children with all 12 symptoms were diagnosed at an average age of 3.8 years.

Is An Early Diagnosis More Likely to Be Incorrect?

Multiple studies have confirmed that autism can be reliably diagnosed by age two with little risk of that diagnosis being invalidated later. Though early diagnoses may require a more definite diagnosis as the child grows older. 

A 2006 study found that if children with autism were diagnosed at age two, that diagnosis was very likely to remain consistent by age nine.

However, the study noted that diagnostic stability was less reliable for children whose autism involved less severe presentations, meeting the older definition of PDD-NOS. This conclusion means that children with more typical presentations or who did not outwardly display multiple diagnostic criteria were more likely to affect how soon a child would be diagnosed with autism or have a missed diagnosis. 

While medical knowledge has improved in the 14 years since that study was published, it is still possible for a child to delay presentation of ASD until age five or later

One major factor that can prevent a missed diagnosis is input from parents. Because parents can observe some of the subtler signs or pervasive patterns that a single diagnostic test might miss, clinicians can perform a more thorough diagnosis or re-evaluate as the child ages.

Advances Lower Average Diagnostic Age

The possibility of a child being diagnosed with ASD at a young age and having that diagnosis overturned is low, while the possibility of an overlooked diagnosis is much higher. Parents concerned that their child has been misdiagnosed with ASD can always seek a second opinion or they can have the child re-evaluated after a few months. 

But parents who disregard early symptoms could be limiting their child's ability to progress, learn, interact with peers, and thrive. The opportunity for early intervention ABA therapy will equip them with the tools and knowledge to thrive alongside their peers instead of lagging behind.

For this reason, parents are urged to follow the American Academy of Pediatrics' recommendation and have their child screened around 18 to 24 months. If they do not, they should still closely observe their child's behaviors in preschool, during play, and when interacting with peers for signs of possible ASD.

Early diagnosis and intervention is crucial for helping the child develop skills that can help them lead a fulfilling life, and it can help parents provide the proper care. Therapeutic Pathways uses evidence-based and results-driven ABA therapy to help children with autism thrive while building skills in communication, self-help, social skills, language and speech skills, behavior management and more. 

Get a diagnosis any time you suspect your child might have one or more signs of autism. If they do have ASD, visit an evidence-based autism treatment center that can help you and your child build a better life together.