April is autism awareness month (April 2 was autism awareness day), during which people are encouraged to learn more about autism spectrum disorder, increase awareness about the issue, and remember to be kind. There are also online events for people with autism and their families.
So what is autism spectrum disorder? It's complex, and affects people differently, but it affects people's communication, social skills, relationships, and self-regulation, and can cause a person's behaviors, interests, and activities to be restricted or repetitive. These symptoms often arise in early childhood, and they may persist throughout a person's life. They may also interfere with daily life. Many people on the autism spectrum have sensory issues that can make them under- or over-sensitive to light, touch, sound, or other stimuli.
As of 2018, the Centers for Disease Control and Prevention estimated that in the United States, about one in 59 people have autism, a rate that's twice as high as 2004. While this may indicate that the incidence is rising, it may also simply be a reflection of greater awareness of the disorder by clinicians that diagnose it.
There is currently no standard diagnostic test, like a blood test, for autism.
White boys are most likely to be diagnosed, but autism can affect anyone. Studies have suggested that some kids are not diagnosed because they and their families lack access to healthcare or don't speak English as their primary language. Girls may also go underdiagnosed because their symptoms present differently than boys, and we're still learning about autism in girls. Autism can be diagnosed reliably in children as young as two, though the average age of diagnosis is four. Affected individuals who are minorities tend to be diagnosed later.
It's important for those that are affected to be diagnosed early because interventions are most effective at treating the disorder when they're applied early. Applied Behavior Analysis (ABA) is one treatment approach that involves implementing habits, like positive behaviors, that help children with autism develop the skills they need as an individual. This method might encourage kids to speak to their peers, increase their attention span, or reduce challenging behaviors, for example.
Research into the causes of autism spectrum disorder is ongoing. Studies have found that small changes in some genes are associated with a higher risk of autism, and the disorder tends to run in families. These genetic factors are complex, however; there does not appear to be an 'autism gene.' Changes in the number of copies of some genes may also play a role. Some people with certain diseases are more likely to have autism, like fragile X syndrome and tuberous sclerosis. Some differences in the biology of the brain have been observed in people with autism compared to neurotypical people.
The gut microbiome, which has been shown to play an important role in human health, has also been proposed as a culprit in autism development.
There are also environmental factors that have been linked to autism, such as advanced ages in either or both parents (one study that found a link defined advanced age as over 35 for mothers and over 40 for fathers). Low birth weight, extreme prematurity, and pregnancies occurring within a year of another have higher risks of autism as well.
Autism may arise around the same age that children receive standard vaccines. Repeated studies have not found any link between vaccines and autism.
Sources: Autism Speaks Inc, Autism Society, Centers for Disease Control and Prevention, American Journal of Epidemiology