5 Reasons Why an Autism Diagnosis Is Missed

The late diagnosis of autism spectrum disorder (ASD) is not uncommon given the wide variation of autism symptoms. ASD can be missed if a person doesn't have behaviors or traits that are immediately recognized as neurodivergent (different than others) or is able to mask those behaviors and appear neurotypical (the same as everyone else).

Some autistic people are able to communicate verbally, get along with neurotypical peers, and have socially appropriate interests and interactions. It is only in later life when responsibilities and relationships become more complicated that ASD traits may be "unmasked."

This article lists five reasons why some autistic people remain undiagnosed or are only diagnosed at a later age.

Teenage girl talks to school counselor
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Academic Performance

Many autistic children who aren't diagnosed often display average or excellent performance in school. Because of this, their autism will go unnoticed, causing parents and teachers to search for other explanations for behaviors that seem unusual or problematic.

Even experienced pediatricians can miss the diagnosis when a young child is communicating verbally and reaching the expected developmental milestones. In some cases, a child's scholastic strengths can carry them through elementary school with only minor behavioral or social concerns.

However, as schoolwork becomes more abstract and demanding in middle school or high school, a child may start to exhibit classic signs of ASD—such as rocking, lack of eye contact, and obsessive behaviors—that some might misconstrue as anxiety or signs of social maladjustment.

As schoolwork and social interactions get more complicated, autistic people may engage in more intense self-regulatory behaviors like stimming (repetitive or unusual body movements or noises) or echolalia (meaningless repetition of words) to help calm and soothe themselves.

Outbursts or meltdowns triggered by sensory overload may cast a child as being "difficult" or "troubled," distancing them from peers and counselors who might otherwise offer support.

Some will only show signs during adulthood after a major life change, such as graduating college, starting a job, or having children.

Early Misdiagnoses

Children are generally diagnosed with autism by the time they are 4 years old. After that time, it is not uncommon for traits to be missed or attributed to some other condition such as:

The older and older the child gets, the less likely that autism will be diagnosed simply because they don't fit the classic profile of ASD.

According to a 2019 study in the journal Autism, 10.3% of autistic adults were incorrectly diagnosed with ADHD as children, while 12.1% of children initially diagnosed with ADHD were subsequently diagnosed with autism.

Signs of Autism in Adults

Autism traits in adults include:

  • Anxiety over social situations
  • Appearing blunt, rude, or disinterested without meaning to 
  • Avoiding eye contact
  • Difficulty making friends
  • Difficulty understanding what others are thinking or feeling
  • Finding it hard to say how you feel 
  • Having a very keen interest in very specific subjects
  • Maintaining strict routines and being anxious if they change
  • Not understanding social rules
  • Noticing patterns, smells, or sounds that others do not
  • Preferring to be alone
  • Taking things literally


Changes in Criteria

Another reason for a missed diagnosis is that a person may have been born before the definition was revised in the Diagnostic and Statistical Manual of Mental Health Disorders, Fifth Edition (DSM-5).

Prior to the release of the DSM-5 in 2013, subtypes of autism such as Asperger's syndrome and pervasive development disorder-not otherwise specified (PDD-NOS) existed. With the release of the DSM-5, those sub-classifications were dropped and autism was described as a broad range (spectrum) of traits and behaviors.

The change in definition led some children to fall out of care when their diagnosed condition was no longer considered "real." It is only in later years that a person might seek a new diagnosis when ASD traits start to negatively impact their life.

Gender Disparities

Studies have shown that autistic females are four times less likely to be diagnosed than autistic males. While gender bias plays a major role in this disparity, there are other factors that contribute.

A 2015 study in Molecular Autism suggests that females may be genetically "immune" to some of the challenges of ASD—a concept referred to as the "female protective effect." For reasons unknown, autistic females tend to have better functional social behaviors than males.

At the same time, it may be that certain ASD traits may be more "problematic" in males than females. For instance, difficulties with motor coordination might raise a red flag in males who play sports but be entirely missed in females who are often assigned different social roles and expectations.

The same may occur if a male is seen to be shy and non-communicative as opposed to females, who are expected in many cultures to be shy and reticent.

A Note on Gender and Sex Terminology

Verywell Health acknowledges that sex and gender are related concepts, but they are not the same.

  • Sex refers to biology: chromosomal makeup, hormones, and anatomy. People are most often assigned male or female at birth based on their external anatomy; some people do not fit into that sex binary and are intersex.
  • Gender describes a person's internal sense of self as a woman, man, nonbinary person, or another gender, and the associated social and cultural ideas about roles, behaviors, expressions, and characteristics.

Research studies sometimes don't use the terminology in this way. For example, terms that describe gender (“woman,” “man”) may be used when terms for sex (“female,” “male”) are more appropriate. 

To reflect our sources accurately, this article uses terms like "female," "male," "woman," and "man" as the sources use them.

Socioeconomic Factors

Income and race affect almost every aspect of healthcare in the United States, and ASD is no exception. Children of color, especially Black children, are more likely to be misdiagnosed or diagnosed with autism later in life due to systemic racial biases.

Because of this, Black, Latinx, or Asian children are less likely to be diagnosed with ASD than White children, according to a 2021 study in the Journal of Developmental and Behavioral Pediatrics.

Of the over 260,000 autistic children included in the study. one-quarter were diagnosed—the vast majority of whom were Black or Latinx. Statistically, Black children with autism were 2.6 times more likely to be undiagnosed than White children.

Cultural misperceptions also contribute to the disparity. One study found that Black parents of children with ASD expressed fewer concerns about repetitive and social behaviors than White parents. A lack of awareness about autism is thought to play a central role.

Barriers in language also contribute to lower rates of diagnosis in Latinx and Asian communities.

Is a Late Diagnosis Worth It?

While there are benefits to diagnosing autism at any age, there are also barriers that can make diagnoses challenging. The hardest part may be convincing your healthcare provider to even start the process.

According to a 2017 study in the Journal of Autism and Developmental Disorders, the main reason that autistic adults delay seeking a diagnosis is because they fear their providers will not believe them. The cost of treatment, stigma, and the inability to explain their symptoms are also significant barriers.

Even so, the benefits of a diagnosis tend to outweigh the consequences. Many adults find that a formal diagnosis brings a sense of relief and confirmation that there are legitimate reasons for their issues.

It also allows them to connect with services and support that can help them better cope with certain challenges. This includes accessing treatments like:

Summary

Many autistic people are misdiagnosed or go undiagnosed until a later age. Among the reasons for this are changes in autism definitions, gender bias, racial bias, and unequal healthcare access.

Older autistic children and adults are often able to mask their symptoms. It is only later in life when responsibilities and relationships become more complicated that a person might exhibit overt signs of ASD.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Lisa Jo Rudy
Lisa Jo Rudy, MDiv, is a writer, advocate, author, and consultant specializing in the field of autism.