Autism is identified more now than in the past, and some wonder whether it’s being overdiagnosed. We take a closer look at the research.
There was a time when autism was something you only heard about. Now, there’s a good chance you know an autistic person, or there may be one or two in your child’s class at school. Maybe you or your child are autistic.
Growth in autism awareness and new diagnostic criteria are two examples of factors that might account for the increased diagnosis rates.
Still, there are those who wonder whether there’s an autism epidemic or whether mental health professionals are overdiagnosing autism.
Data from the
These numbers, as shown in the table below, make it clear that autism diagnosis rates are increasing — but the cause is still up for debate.
|Surveillance year||Birth year||Diagnosis rate|
|2000||1992||1 in 150|
|2002||1994||1 in 150|
|2004||1996||1 in 125|
|2006||1998||1 in 110|
|2008||2000||1 in 88|
|2010||2002||1 in 68|
|2012||2004||1 in 69|
|2014||2006||1 in 59|
|2016||2008||1 in 54|
|2018||2010||1 in 44|
Some people believe that diagnostic rates are higher than necessary. Others feel that current rates include autistic people who may have been missed in the past.
1. A new understanding of autism
The change from a narrow description of autism to a broader one may interfere with building mechanistic models of autism, according to the study.
A mechanistic model is a sample of something. Without a clear sample, some people fear that the diagnosis of autism could have less meaning. This may lead to a wider definition of autism, resulting in more frequent diagnoses.
A 2021 study identified four scenarios where an autism diagnosis may not be helpful:
- when the diagnostic tools raise uncertainties about the diagnosis
- when the person has a subclinical (less obvious) presentation
- when early signs of autism fade during development
- when other conditions are present
Because autism diagnosis is still based on behavior, it can be hard for clinicians to tell the difference between autistic people, neurotypical people with autistic traits, and people with other neurodevelopmental or psychiatric conditions.
2. There’s more support available to help kids thrive
In some situations, childhood funding is set up to support autism more than other diagnoses. Examples of this include specialized schools and teacher-student ratios. An autism diagnosis may also generate financial aid.
Some therapies, such as applied behavior analysis, are only available in certain states and with certain insurance companies if the child has a diagnosis of autism.
It’s possible that more children are referred for autism assessments so that they can access this support.
3. Diagnosis may be rushed
The upside of early diagnosis is that it can direct helpful support to autistic kids. In well-intentioned efforts to access this support, children may be receiving finalized autism diagnoses too early.
Instead, provisional diagnoses that include support with follow-up assessments might be more appropriate, to prevent misdiagnosis.
4. Autism may have been underdiagnosed in the past
It’s also possible that current diagnosis numbers reflect a truer picture of autism rates. Milder versions of autism that were previously missed are now more likely to be identified.
It’s easier to mask a milder version of something. Masking is a person’s ability to hide traits of a condition, like ADHD masking or autism masking. The goal of masking is to make it easier to fit in with typical society.
Masking may still interfere with autism identification, as indicated in a 2019 study that looked at compensatory strategy use in autism. The study recognized that some autistic adults hide autistic traits well enough to avoid diagnosis.
On the surface, masking seems like a useful coping strategy until you consider that it can be exhausting, stressful, and may contribute to mental health issues.
Changes to the diagnostic process have contributed to the increased autism rates.
In the 1940s, autism was first identified as occurring in children. Now experts recognize autism in people of all ages.
The current version of the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) has reclassified several previously separate conditions:
- autistic disorder
- Asperger syndrome
- childhood disintegrative disorder
- pervasive developmental disorder not otherwise specified (PDD-NOS)
Now they exist together under the umbrella of “autism spectrum disorder.”
It’s possible for an autism misdiagnosis to occur.
An allistic person can be mistakenly identified as autistic. Alternatively, a person can be diagnosed with something else when they’re actually autistic.
It’s also possible for an autistic person requiring minimal support to need more than one assessment before their autism is identified. They may mask their differences well enough that they seem to fall short of the diagnostic criteria.
However, this doesn’t mean that their differences are insignificant or that they wouldn’t appreciate support.
Characteristics sometimes confused with autism include:
- hearing problems
- speech delays
- developmental delays
- early reading
- specialized interests
- sensory processing differences
Sometimes traits of autism appear in other psychological diagnoses, such as:
- attention deficit hyperactivity disorder (ADHD)
- avoidant personality disorder
- reactive attachment disorder
- obsessive-compulsive disorder (OCD)
- social (pragmatic) communication disorder
Lead poisoning can also mimic the developmental delays that sometimes occur with autism.
Doctors used to believe that the signs of autism were part of schizophrenia spectrum disorder. Sensory and communication differences are two examples of characteristics that were misunderstood.
Now, clinicians understand that autism is a separate cognitive profile and exists on a spectrum. In some people, the signs are obvious, while in others they can be subtle and not immediately recognizable.
Specialists diagnose autism by assessing a person’s behavior.
They start by comparing developmental milestones against those of typically developing children using parent forms and questionnaires.
If enough signs exist to indicate that autism might be present, they conduct more tests, such as:
- Autism Diagnostic Interview-Revised (ADI-R). The ADI-R is a parent interview to evaluate past and present child behaviors that might indicate autism.
- Autism Diagnostic Observation Schedule (ADOS-2). This is an age-specific test with modules that assess for traits like repetitive behavior and communication differences.
- Childhood Autism Rating Scale Second Edition (CARS-2). This 15-question test can help diagnosticians separate the presence of autism from other conditions.
Clinicians also perform tests to check for other issues that may cause symptoms, like hearing, vision, or motor skill differences.
Autism exists on a spectrum. This means that no two autistic people are exactly alike.
Some people might present clear signs that they’re autistic. They may have noticeable support needs, like communication differences, and exhibit behaviors that allistic people don’t understand.
Other autistic people may be more like icebergs, with only a few signs visible. Meanwhile, their skill at masking keeps other autism characteristics hidden below the surface. Social confusion, difficulty with change, and auditory processing issues are some examples.
As autism awareness increases and diagnostic procedures adapt, more autistic people can be identified and offered helpful services. Greater availability of these services may also increase the rate at which children are referred for assessments.
To learn more about autism, you can visit Psych Central’s autism resource hub.