While there is no universal definition of "high-functioning autism," it remains an important distinction: ASD can otherwise be missed if a person doesn't have overt signs and symptoms, such as difficulty with communication, inappropriate social interactions, and repetitive or obsessive behaviors.
Therefore, it appears that while some individuals may be aware they are autistic, others may not fully understand why they have difficulties connecting with people socially or engaging in conversation - yet still realize they are 'different.
Level 1 is the mildest, or “highest functioning” form of autism, which includes those who would have previously been diagnosed with Asperger's syndrome. Individuals with ASD level 1 may have difficulty understanding social cues and may struggle to form and maintain personal relationships.
Although 2019 research suggests some symptoms of ADHD and ASD overlap, there are distinct differences. A person with ADHD may have attention, hyperactivity, and impulsivity challenges. But an autistic individual may have difficulties with communication, social interaction, and restricted or repetitive behaviors.
There are other brain disorders that mimic autism symptoms, like ADHD and anxiety disorders, including selective mutism. Autism can be misdiagnosed as another disorder with some shared symptoms.
Autistic people may act in a different way to other people
find it hard to understand how other people think or feel. find things like bright lights or loud noises overwhelming, stressful or uncomfortable. get anxious or upset about unfamiliar situations and social events. take longer to understand information.
In some ways Williams syndrome is the opposite of autism. For example, people with Williams syndrome love to talk and tell stories, whereas those with autism usually have language delay and little imagination. Many people with Williams syndrome draw disjointed pictures, some with autism draw pictures in perfect detail.
However, autism symptoms can show up later in higher-functioning individuals when they're under more demand or challenge, making an adult autism diagnosis possible. In addition, some adults who were not diagnosed in childhood may be later diagnosed in adulthood.
We know that there's no one cause of autism. Research suggests that autism develops from a combination of genetic and nongenetic, or environmental, influences. These influences appear to increase the risk that a child will develop autism.
This may include avoiding bright lights and noises, preferring to be alone, and being rigid about rules. This does not make them autistic. However, a person can be mildly autistic. Mildly autistic people are unable to understand the body language or emotions (sarcasm, pain, and anger) of the people around them.
Some people on the autism spectrum may seek social opportunities and may initiate social interactions themselves, others may enjoy social situations and interactions when they are initiated effectively by others.
Someone who is considered a savant may be especially skilled in art, math, music, memory recall, or another subject. Savant syndrome is commonly associated with autism but can occur alongside other conditions.
Many biological conditions can lead to social difficulties, including autism. However, not all autistic individuals will display social awkwardness (though they may struggle inwardly). Moreover, not everyone who is socially awkward is autistic. And, in fact, they don't necessarily have a diagnosable condition.
It is estimated that worldwide about 1 in 100 children has autism (1). This estimate represents an average figure, and reported prevalence varies substantially across studies. Some well-controlled studies have, however, reported figures that are substantially higher.
Key Autism Statistics
According to the CDC, as of 2023, around 1 in 36 children in the U.S. has been diagnosed with autism. Around 75 million people have autism spectrum disorder, that's 1% of the world's population. 1 in 100 children are diagnosed with autism spectrum disorder as of 2021.
Attention deficit hyperactivity disorder (ADHD) and autism can look a lot like each other. Children with either condition can have problems focusing. They can be impulsive or have a hard time communicating. They may have trouble with schoolwork and with relationships.
Asperger's syndrome.
This is on the milder end of the autism spectrum. A person with Asperger's may be very intelligent and able to handle their daily life. They may be really focused on topics that interest them and discuss them nonstop. But they have a much harder time socially.
These children are often notably awkward, and they find nonverbal interaction especially complicated, specifically in situations involving eye contact, sensory sensitivity, spatial awareness, and interpersonal communications.
Children with level 3 autism often find it challenging to develop their communication and social skills. They are likely to be non-verbal and unable to use spoken language when interacting with other people, and may even be unaware there are people around them.