It makes sense that the term autism literally means “aloneness” or “living in one’s own world.” Children who are affected by this common neurological disorder typically experience the kind of delays and impairments in social skills, behavior, nonverbal communication, and speech that make it difficult for them to understand or relate to other people’s emotions and perspectives.

Autism is a developmental disorder, meaning its initial symptoms always appear — even if they aren’t always recognized — within the first few years of life. Autism is also a spectrum disorder, meaning its symptoms and severity can vary greatly from person to person.

Although autism was relatively rare for many years, its prevalence has increased dramatically in recent decades: Before the 1990s, about 1 in 2,000 children in the United States were affected by the disorder, but today approximately 1 in 59 American children live with autism.

As autism has become more common, experts have improved their understanding of the disorder, fine-tuned their diagnostic skills, and developed an exhaustive, multifaceted treatment approach designed to help improve each aspect of impairment, delay, or dysfunction.

But even though we now know that most of the defining indicators of autism often emerge by a child’s second or third birthday — and that early diagnosis and intervention can lead to much better outcomes later in life — autism diagnoses are routinely delayed. Here’s what you should know.

Delayed autism diagnoses: Why the hesitation?

Years of research shows that parents of children who are eventually diagnosed with autism typically notice significant developmental differences in social, communication, or fine motor skills before their child’s first birthday — often as early as 6 months of age.

Research also shows that, although it’s often possible to provide an autism diagnosis by a child’s second birthday, most children who are affected by the disorder aren’t diagnosed until they’re almost five years old.

This may not seem like a significant amount of time until you consider the fact that early intervention can have a major impact on later development. Here are a few of the main reasons that autism diagnoses — along with crucial early intervention — are often delayed.

High-function delay

Children who fall on the high-functioning end of the autism spectrum tend to be diagnosed much later than children on the lower-functioning end of the spectrum.

That’s because higher-functioning children typically don’t have the language delays that point to a more severe form of autism early on. They’re also less likely to have the intellectual delays that lead to developmental delays or learning disabilities.

Instead, children on the high-functioning end of the autism spectrum are more likely to have difficulty with social interactions, especially among their peers. And this red-flag symptom is more likely to first emerge in preschool, when the “rules” of social behavior start to become more complex.

Misdiagnosis delay

As a spectrum disorder with a wide range of potential symptoms and behaviors, autism has a lot in common with other spectrum developmental conditions, including attention-deficit hyperactivity disorder (ADHD).

And because clinicians and parents tend to gravitate toward the diagnosis with the best prognosis, young children are often diagnosed with ADHD — or some type of sensory processing issue — long before their autism is officially identified.

Early red flags of autism

Learning how to recognize the early signs of autism is one of the best ways to ensure children with autism receive a timely diagnosis and essential early intervention care.

As with later symptoms, the nature, severity, and timing of early autism symptoms vary widely among young children. Some infants show signs of the disorder in their first months of life, while others don’t have any obvious symptoms before their first birthday.

Early indicators of autism include:

• Limited or no eye contact by 6 months of age
• Few big smiles or other happy expressions by 6 months of age
• Few smiles or reciprocate sharing of sounds by 9 months of age
• Little or no babbling by 12 months of age
• Absence of reaching, pointing, or waving by 12 months of age
• Very few words or no speech at all by 16 months of age
• Very few meaningful two-word phrases by 24 months of age

Avoidance of eye contact, repetitive behaviors like rocking or flapping, and any loss of previously acquired speech or social skills may also be considered red flags for autism at any age.

If you suspect your child might be on the autism spectrum, it’s important to bring them in for a proper diagnostic evaluation as soon as possible.

To learn more about an autism assessment, our diagnostic process and treatment, call the Abbey Neuropsychology Clinic at (650) 614-0014 or request a consultation using the online booking tool.