What Is Autism?

This informational guide, part of POPSUGAR's Condition Center, lays out the realities of this health concern: what it is, what it can look like, and strategies that medical experts say are proven to help. You should always consult your doctor regarding matters pertaining to your health and before starting any course of medical treatment.

Autism spectrum disorder (known as ASD or, simply, autism) is estimated to affect roughly one in 44 children and one in 45 adults in the US. Despite its prevalence, there are a number of misconceptions about this diverse disorder — chiefly that it always presents the same way.

This lack of understanding of the true range of autism behaviors may be one reason some people with the disorder go undiagnosed until they're older. But research has shown that delayed diagnosis may result in a reduced quality of life because people are left to find ways to make sense of and manage their symptoms on their own. That's why it's essential to learn about the spectrum of symptoms that make up autism and all the different ways they can present in kids and adults with the disorder — as well as the therapies that can change people's lives.

Autism spectrum disorder is considered a developmental disorder that impacts the nervous system. The group of developmental disabilities that are considered ASD are associated with a variety of shared symptoms, including persistent problems with social skills, speech, and nonverbal communication; repetitive movements; ritualistic behaviors; restricted interests; and sensory sensitivities. ASD also includes conditions that were once considered their own diagnoses, including Asperger's syndrome and pervasive developmental disorder, notes the US Department of Health & Human Services. (ASD is also sometimes called pervasive developmental disorder.)

Even though signs of the disorder can show up as young as 6 months, fewer than half of children with ASD receive a developmental evaluation by the time they're 3 years old, and 30 percent of children don't receive a formal ASD diagnosis until after age 8, according to a report by the Autism and Developmental Disabilities Monitoring Network. Some, especially those with more subtle symptoms, go undiagnosed into adulthood. Women (or people who are AFAB) are especially likely to be diagnosed later in life due to several factors, notes the Child Mind Institute: girls may exhibit different symptoms than boys or may be more likely to regulate their behavior in public, and people may also be more willing to overlook certain autism symptoms, like having intense interests, in girls due to gender stereotypes.

Being conscious of certain age-related markers in children (such as not responding to name by 9 months old or still using few or no gestures by 12 months old) is important, since early intervention is so beneficial. The American Academy of Pediatrics provides a list of useful screening tools for children.

According to the Mayo Clinic, some symptoms typically associated with autism include:

These are just a few common signs and symptoms. This condition exists on a spectrum and symptoms can differ from person to person. It's also important to note that kids aren't the only ones who can display signs of autism. Awareness of ASD has grown in the last decade, and as a result, more adults may be starting to realize they may be on the spectrum. "When an adult is considering a possible diagnosis, looking into how they learned and acted as a child can be very helpful, because a lot of times, they learn to mask (pretend to be someone they are not in order to fit in, keep a job, not be bullied, etc.) without even realizing it," says Andi Putt, MS, CCC-SLP, a speech language pathologist who specializes in autism assessment. "As a result, the signs are a lot more subtle in adults because they have had a lot of time to learn how to either hide or accommodate their needs."

No single cause of autism has been identified, but experts have cited factors that may play a role in the development of the disorder.

Autism isn't always easy to spot, but in children, it's usually flagged during developmental checkups by their provider who will refer them to a specialist (e.g. child psychiatrist, neurologist, or developmental pediatrician) for further evaluation and an official diagnosis, per Mayo Clinic. There is not only single test experts use to diagnosis autism, however. Experts will often do so through behavioral observation and interviews using criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).

In adults, self-evaluation typically comes first as you may notice signs and symptoms of autism in yourself and then seek the help of a mental health professional. If you think you may have ASD, Cleveland Clinic recommends reaching out to an adult psychiatrist or psychologist who works with people who have autism for assessment and diagnosis.

That said, diagnostic testing for autism can be costly and inaccessible. If that's the case, consider asking your doctor about potential grants and financial assistance programs or have a conversation about self-diagnosis and therapies that may be available to you (more on that below!).

Neither autism nor its characteristic behaviors (like stimming, or repetitive body movement or noises) are things that need to be "fixed" with treatment. But there are certain therapies and interventions that can improve the quality of life for children and adults with autism. Putt usually recommends speech therapy and occupational therapy. Speech therapy can help in the development of functional communication (which may be speaking verbally, using sign language, or speaking on a device such as an iPad), self-advocacy skills, and language skills. Occupational therapy is often used to help address sensory needs, feeding, and fine motor skills. The CDC also notes that behavioral, educational, social-relational, psychological, and pharmacological therapies may be helpful.

Applied Behavior Analysis, or ABA, is another therapy frequently recommended by doctors and autism evaluators. This method uses positive reinforcement to promote language and communication skills; improve attention, focus, and social skills; and decrease certain behavior habits. That being said, ABA "has been widely spoken out against by the autistic community for a variety of reasons, including focusing on compliance over relationships, trust, functional communication, and respecting sensory needs," Putt says.

In general, the best approach for one person may not be the best for another; just as every case of autism is unique, the same goes for the therapies people choose to utilize. For some adults with autism, simply getting a diagnosis can be validating. "Knowing and understanding your own neurology can really be life changing," Putt says. According to a research article in the journal PLOS One, "Many adults [in the study], but not all, saw receiving an autism spectrum diagnosis as an end-point that would provide validation and an explanation for feeling throughout their lives that they were 'different' from others." A diagnosis may also become an opportunity for adults to receive useful treatment and support if desired, the study notes.

Alexis Jones is the senior health editor at POPSUGAR. Her areas of expertise include women's health, mental health, racial and ethnic disparities in healthcare, diversity in wellness, and chronic conditions. Prior to joining POPSUGAR, she was the senior editor at Health magazine. Her other bylines can be found at Women's Health, Prevention, Marie Claire, and more.

Ginny Graves is an award-winning writer in the San Francisco Bay Area whose work focuses on science, psychology, health, nature, and the human-animal bond.