One in every 44 children in the United States is diagnosed with autism spectrum disorder. But can autism be developed at a later age? Research indicates that the condition is always present early on, however, it may be diagnosed late for a variety of reasons. Read on to learn more.
Can You Develop Autism?
Autism spectrum disorder is a neurodevelopmental disorder. It is thought to be a result of disruptions in the normal growth of the brain and central nervous system early in development. This means that the condition is present at birth and can’t be developed later in life.
There is no official diagnosis of acquired or late-onset autism. If a person had a completely normal childhood but starts showing autism-like symptoms in adulthood, these signs are typically due to other similar conditions rather than autism.
In the following section, we list the most common early signs and symptoms of autism spectrum disorder.
The earliest signs of autism that would require evaluation by an expert are:
- Not responding when you call the child’s name
- Avoiding eye contact
- Refusing physical contact
- No smiling or displaying other types of social responsiveness
- No babbling
- No pointing at objects and toys by age one
- No single words by 16 months or two-word phrases by age two
Other typical symptoms of autism present in toddlers and young children include:
- Failure to understand social cues and gestures
- Inability to grasp their own feelings and those of others
- Difficulty expressing emotions
- Repeating the exact words or phrases uttered by others, also known as echolalia
- Providing unrelated answers when asked questions
- Systematically using the pronoun “you” instead of “I”
- Sensory sensitivities, such as feeling overwhelmed by bright lights, noise, or touch
- Repetitive body movements like rocking, flapping, spinning, and running back and forth
- Ritualistic behaviors, for example, lining up toys and performing actions in a set order
- Resistance to any change in routines
- Abnormally focused interest in specific topics or objects.
Autism symptoms vary greatly depending on the child’s age and the severity of the disorder. Not all children will have all the above symptoms. Some may also experience other signs that are not on the list.
The early symptoms of autism spectrum disorder are often noticeable from a very young age, by 12 -18 months. However, many of the social and communication issues related to autism don’t appear before the child starts preschool and begins interacting with peers. Children with high-functioning autism may go undiagnosed until social and other challenges arise in school.
Age Limit for Autism Development
According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), in order to qualify for an autism spectrum disorder diagnosis, symptoms must appear during early childhood, before age 3. It is not possible for older children, teenagers, and adults to develop autism.
Some children who appear to develop normally in the first year of life, can go through a period of regression and start showing the symptoms of autism, such as impaired verbal and nonverbal communication skills, between 18 and 24 months. This condition is known as regressive autism. However, researchers believe that children don’t suddenly develop symptoms of regressive autism, but that subtle signs are present even before the regression took place.
Although autism doesn’t appear after early childhood, some people are not diagnosed until their adult years. Below, we explain the main reasons for a delayed diagnosis of autism.
Delayed Autism Diagnosis
In its first report on adults with autism in 2021, the CDC estimates that 2.21% of people over the age of 18 in the United States are living with an autism spectrum disorder. However, it is essential to keep in mind that there is a difference between the late onset of symptoms and a delayed autism diagnosis.
Autism symptoms in adults
The most common symptoms of autism spectrum disorder in adults include:
- Difficulty interpreting what others are thinking or feeling
- Trouble understanding facial expressions, gestures, or social cues
- Challenges when it comes to regulating emotions
- Trouble keeping up a conversation
- Difficulty maintaining natural conversation flow
- Tendency to engage in monologues on a favorite topic
- Speaking with an inflection that does not reflect feelings
- Engaging in repetitive behaviors
- Participating in a restricted range of activities
- Strong attachment to daily routines
- Excessive focus on special interests and topics.
Causes of delayed autism diagnosis
Some adults seek out an autism diagnosis because they believe that they have one or more of the symptoms of autism mentioned above. There are several reasons why a person may not have been formally diagnosed with ASD in childhood:
- Symptoms don’t have a significant impact and don’t limit everyday functioning. Mild autism symptoms in children with high-functioning autism may be difficult to recognize and are easily overlooked.
- The person has received another diagnosis that could explain some of the symptoms.
- Individuals who have been living with autism for a long period of time may become good at masking its symptoms.
- Girls are less likely to receive an accurate autism diagnosis than boys. They are expected to behave in quieter and less assertive ways and are better at hiding their symptoms. In addition, some of the more obvious signs of autism, such as repetitive behaviors, are more often present in boys.
Conditions that can be mistaken for autism
In some cases, the underlying issue of autism-like symptoms is not autism at all. Some individuals who appear to suddenly behave in a way typical for people with autism may have developed another mental health issue.
Autism-like conditions that appear in early adulthood include:
- Generalized anxiety disorder (GAD)
- Avoidant personality disorder (AvPD)
- Reactive attachment disorder (RAD)
- Obsessive-compulsive disorder (OCD)
- Social phobia and other phobias.
Similarly to autism, all of these disorders have a significant impact on an individual’s ability to function effectively and communicate with others and require treatment.
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