Authored by Mercura Wang via The Epoch Times (emphasis ours),
Autism spectrum disorder (ASD), or just autism, is a neurological and developmental condition that affects social interaction, communication, learning, and behavior. It encompasses a range of conditions related to brain development.
Globally, around 1 percent of children have autism. In the United States, however, one in 36 children and one in 45 adults have autism, with the condition affecting around 4 percent of boys and 1 percent of girls. The prevalence is up from one in 44 in 2020 and has almost tripled since 2000 when it was one in 150.
“On the spectrum” refers to individuals who share core characteristics of autism while recognizing that each person’s autistic experience is unique, complex, and can change over time.
Thinking about autism as on a linear spectrum can be misleading, as it suggests a person can have “more” or “less” autism, leading to oversimplified labels such as “higher” or “lower functioning.” Instead, autism is better understood as a range of diverse traits, strengths, and challenges that vary for each individual.
The first signs of autism typically appear in early childhood and can be detected through screening in children as young as 12 months old or as old as 24 months. However, the condition may be missed until much later.
Early signs of ASD by age include the following:
The following are common behaviors observed in individuals with ASD. While not all autistic individuals exhibit every behavior, most will show several traits. Some of these behaviors can also occur in people without ASD.
Social interactions:
Restrictive or repetitive behaviors:
People on the autism spectrum often have notable strengths, such as the ability to learn and retain detailed information, strong visual and auditory learning skills, and excellence in memory, math, science, music, or art. They may also notice subtle details, patterns, smells, or sounds that others may overlook.
Autism symptoms in women and girls may be different from those in males. According to the DSM-5-TR, autistic females may exhibit:
Research indicates that females are more likely to mask their autism symptoms to fit in than males. They may stay close to peers and move in and out of activities, regardless of engagement status.
Research indicates autism arises from a combination of genetic and environmental factors, as well as abnormal brain development.
Genetic factors are believed to contribute 40 percent to 80 percent of autism risk. Over 1,000 genes have been linked to ASD, although many associations remain unconfirmed. Common gene variations may increase ASD risk, but most have a small individual effect, and not everyone with these variations develops ASD.
In about 2 percent to 4 percent of cases, rare gene mutations or chromosomal abnormalities are a direct cause, as with ADNP syndrome, also known as Helsmoortel-Van der Aa syndrome (HVDAS). Some other genes whose rare mutations are associated with autism include ARID1B, ASH1L, CHD2, CHD8, DYRK1A, POGZ, SHANK3, and SYNGAP1. Many ASD-associated genes play roles in brain development or regulate other genes or proteins.
In some children, autism may be linked to a genetic condition such as fragile X syndrome or Down syndrome.
Research suggests that during brain development, individuals with ASD may have an excess of neurons and overgrowth in parts of the brain’s outer layer, the cortex. Additionally, there are irregular areas where the typical structure of the cortex is disrupted. The cortex normally has six layers, formed before birth, each with specialized neurons and connections. These abnormalities are seen in the frontal and temporal lobes, regions involved in emotions, social behavior, and language. These differences are believed to contribute to the social, communication, and cognitive challenges associated with autism.
Other parts of the autistic brain that exhibit abnormalities include the cerebellum and the amygdala. However, it is unclear whether these brain changes spur autism or vice versa.
Environmental factors can range from infections and diseases to toxins and maternal health during pregnancy. They include:
Although authoritative organizations such as the World Health Organization (WHO), the American Academy of Pediatrics (AAP), and the U.S. Centers for Disease Control and Prevention (CDC) assure parents that there is no link between childhood vaccines and autism, some scientists call for further study.
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