Autism spectrum disorder (ASD) refers to a range of conditions characterized by challenges with social skills, repetitive behaviors, speech and nonverbal communication. According to the Centers for Disease Control and Prevention (CDC), about 1 in 44 children has been identified with ASD.
Autism occurs in all racial, ethnic and socioeconomic groups but is about 4 times more common among boys than among girls. Some signs of autism can often be detected at 18 months or younger. By age 2, a diagnosis by an experienced professional can be considered very reliable. However, many children do not receive a final diagnosis until much older.
Early diagnosis is key to getting the right interventions and supports for autism. The earlier autism is detected and treated, the better the outcome for the child. However, because autism varies widely in its symptoms and severity, there is no set timeline for diagnosis. Some children show signs from birth, while others seem to develop normally and then regress. With appropriate developmental screening and monitoring, autism can often be reliably diagnosed by age 2. But for others, the signs and symptoms emerge more slowly over time.
When are the first signs of autism noticed?
The behavioral signs of autism often appear early in development, before age 3. According to the CDC’s Learn the Signs. Act Early campaign, some early red flags include:
– By 6 months: No back-and-forth sharing of sounds, smiles or other facial expressions
– By 9 months: No babbling, gestures like pointing, or response to their name
– By 1 year: No words
– By 16 months: No meaningful, two-word phrases
– By 24 months: No meaningful two-word phrases regularly used
However, not all children show these early signs, or their autism characteristics may develop gradually over the second or third year of life. Some children with autism appear to develop typically until around 18-24 months but then start to regress or lose skills they had previously gained. Regressive autism affects about 30% of children with ASD.
According to a 10-year study by the CDC published in 2020, the median age for first evaluation by a qualified professional was over 3 years (37 months) for autistic children born in 2014. But almost half were evaluated by age 2. Early screening at the 18- and 24-month pediatrician visits can help identify possible risk for ASD, prompting earlier evaluation and diagnosis.
Why is there a delay in diagnosing autism?
There are many reasons why autism may not be diagnosed until a child is 3 years or older:
– Variability of symptoms: Autism characteristics and severity vary widely among individual children. Milder or less typical symptoms are harder to recognize.
– Lack of resources: Access to autism specialists who can accurately diagnose autism, especially in remote areas, may be limited.
– False reassurance: Some children may have mild symptoms or progress slowly in their development, falsely reassuring parents their child will “grow out of it.”
– Mistaken identity: Early symptoms like lack of eye contact or limited babbling may be mistaken for normal shyness or delay, rather than autism.
– Regression: Parents whose children appear to be developing typically but then lose skills may not connect the regression with autism.
– Co-occurring issues: Autism symptoms may be masked by accompanying conditions like speech delay or ADHD.
– Denial: Some parents may be in denial about their child’s symptoms and put off having them evaluated.
– Lack of screening: Many children are still not screened for autism risk during regular pediatric visits at 18 and 24 months.
What is the average age for an autism diagnosis?
According to a study by the CDC published in 2020 that looked at over 4,000 autistic children born in 2014, the average age of first evaluation was:
– 36 months for autistic boys
– 38 months for autistic girls
The median age for first comprehensive evaluation was:
– 35 months for autistic boys
– 37 months for autistic girls
And the median age for first autism spectrum disorder diagnosis was:
– 38 months for boys
– 44 months for girls
So while autism can reliably be identified as early as age 2, most children aren’t diagnosed until after age 3. The same study found:
– 43% of autistic boys were diagnosed by age 3
– 31% of autistic girls were diagnosed by age 3
| Age | Percentage of Autistic Boys Diagnosed | Percentage of Autistic Girls Diagnosed |
|---|---|---|
| By 24 months | 16% | 10% |
| By 36 months | 43% | 31% |
| By 48 months | 64% | 50% |
| By 60 months | 77% | 66% |
This data suggests autism is identified later in girls than in boys. Possible reasons for this gender difference include:
– Girls tend to have more subtle symptoms that are harder to recognize
– Boys tend to have more externalizing behaviors that draw parental concern
– Autism screening tools were developed based on boys and may miss girls
– Professionals are more used to diagnosing autism in boys
But age of diagnosis depends on many factors like autism severity, presence of intellectual disability, access to services, and parental concerns.
Early Intervention
The takeaway is that while some children show signs of autism from infancy, most are not diagnosed until after reaching age 3. This delay means missed opportunities for early intervention during the critical window between ages 1-3 when the brain is rapidly developing.
Starting autism behavioral therapies by 18 months can significantly improve outcomes compared to later intervention. That’s why routine developmental screening and monitoring from an early age is so important, even for children who appear to be progressing normally.
How is autism diagnosed?
There is no medical test, like a blood test or brain scan, that can diagnose autism. Trained specialists make the diagnosis by observing the child’s development and behavior and ruling out other possible conditions. The diagnostic process typically involves:
– Developmental screening: The first step at regular well-child visits at 18 and 24 months using autism-specific screening tools. Screens identify children at risk who need further evaluation.
– Comprehensive evaluation: Performed by specialists like psychologists, psychiatrists, neurologists or developmental pediatricians. Includes reviewing parental concerns, medical and developmental history, observing the child and interviewing parents about behaviors.
– Testing for autism: Structured tests aid diagnosis by assessing social interaction, communication, behavior and other areas impacted by autism. The ADOS-2 and ADI-R are commonly used gold-standard autism assessment tools.
– Ruling out disorders: Testing for conditions like hearing loss, intellectual disability and language disorders that overlap with autism.
– Multidisciplinary input: Seeking input from speech therapists, occupational therapists and other professionals involved with the child.
– DSM-5 criteria: The doctor determines if the child meets the criteria for autism spectrum disorder outlined in the Diagnostic and Statistical Manual of Mental Disorders.
– Severity level: If autism is diagnosed, the doctor assigns a severity level (Level 1-3) based on the amount of support needed.
While autism is a lifelong condition, early diagnosis followed by evidence-based therapies and supports offer the best chance for positive long-term outcomes. That’s why screening and monitoring development from an early age is so vital.
Role of pediatricians in diagnosing autism
Pediatricians play a pivotal role in identifying autism at the earliest possible age through:
– **Routine screening:** Checking for developmental red flags at the 18-month and 24-month well child visits using validated screening tools like the M-CHAT questionnaire.
– **Monitoring development:** Tracking children’s progress in social, language and motor skills at every visit. Lack of typical development is a warning sign.
– **Listening to parents:** Valuing parental concerns about atypical behaviors or loss of milestones, and documenting those concerns.
– **Prompt referral:** Referring children with failed screens or other concerns to specialists like psychologists, neurologists or developmental pediatricians for comprehensive diagnostic evaluation.
– **Ongoing care coordination:** Collaborating with the diagnostic team to integrate recommendations into ongoing care plans. Supporting families through the process.
– **Early intervention:** Connecting newly diagnosed children to evidence-based therapies like applied behavior analysis, speech therapy and occupational therapy as soon as possible to improve outcomes.
By providing continuous developmental monitoring and surveillance starting in infancy, referring children with concerns promptly, and partnering closely with autism specialists, pediatricians enable earlier autism identification and life-changing early intervention for affected children.
Can autism be diagnosed at birth?
Autism itself cannot reliably be diagnosed at birth or shortly after, before the emergence of symptoms. However, some conditions identifiable at birth may indicate increased risk for autism later on. These include:
– **Genetic disorders:** Fragile X syndrome, Down syndrome, tuberous sclerosis and other genetic or chromosomal conditions highly associated with autism. Diagnosable through prenatal testing or at birth.
– **Brain malformations:** Structural abnormalities of the brain like enlarged ventricles, identified through ultrasound or MRI around the time of birth. May increase autism risk.
– **Preterm birth/low birth weight:** Babies born significantly preterm or underweight are at elevated risk for autism and other developmental disabilities.
– **Birth complications:** Newborns who experience lack of oxygen, trauma during delivery or other complications may have higher autism risk.
While these perinatal risk factors do not allow diagnosis of autism specifically, they signify the infant should undergo meticulous developmental monitoring and autism screening by 12 months old. Early intervention can then begin promptly if autism does emerge.
But for the majority of autistic children without identifiable genetic or birth risk factors, the diagnosis can only be made after careful observation of emerging social-communication and behavioral signs over the first 2-3 years of life. That’s why screening all children during pediatric well visits is vital for identifying those at risk for autism as early as possible.
Conclusion
In summary, while some infants later diagnosed with autism have identifiable risk factors at birth like genetic disorders, autism itself cannot be definitively diagnosed until behavioral symptoms emerge, usually between ages 1-3. Routine screening for developmental concerns during pediatric visits at 18 and 24 months, followed by immediate evaluation of children with red flags, enables early diagnosis and intervention when treatment is most effective. This improves outcomes for children with autism, allowing them to reach their full potential. The earlier autism is identified, the better the prognosis.