Autism spectrum disorder, also known as autism or ASD, is becoming increasingly common. According to the Centers for Disease Control and Prevention, about 1% of the world – or 75,000,000 people – have ASD. Even more surprising, an estimated 5.4 million (or 2.2%) U.S. adults have ASD. That number may seem large, but ASD features a wide range of symptoms and levels of severity. 

"Autism spectrum disorder occurs in all age, racial, ethnic and socioeconomic groups," says Lisa Neitzke, PhD, BCBA, Nebraska Medicine licensed psychologist and assistant professor of psychology at UNMC/Munroe-Meyer Institute. "While not everyone is diagnosed at an early age, early detection is key to improving outcomes later in life."

Below, we outline five common questions (and answers) about ASD in adults.

1. Can adults be diagnosed with autism spectrum disorder?

Adults can be diagnosed with ASD. Most symptoms typically present before age 18, but others may not fully manifest until later in life, when social demands exceed individual capabilities.

2. What are the signs of ASD in adults?

Some adults with ASD exhibit symptoms that resemble attention deficit hyperactivity disorder or ADHD. Other symptoms may include:

• Difficulty interpreting what others are thinking or feeling
• Trouble interpreting facial expressions, body language or social cues
• Difficulty regulating emotions
• Trouble keeping up a conversation
• Inflection that does not reflect feelings
• Difficulty maintaining the natural give-and-take of a conversation
• Tendency to engage in repetitive or routine behaviors
• Only participating in a restricted range of activities
• Strict consistency to daily routines or outbursts when changes occur
• Exhibiting strong, special interests

3. How is autism diagnosed?

A multi-factorial evaluation is the best tool for diagnosing ASD in adults. The evaluation should include an in-person evaluation as well as a thorough assessment of your developmental history from a parent or caregiver who knew you during your childhood. Sometimes it may be difficult to find an informant like this. If so, a spouse, partner, or close friend can help complete the necessary screenings by reporting on your current behavior.

If you're thinking about seeking an autism evaluation, online ASD assessments can provide a good starting point. However, most online rating scales do not have adequate reliability and validity to provide accurate diagnoses, and they don't take into account your developmental history. Therefore, clinical expertise is required to correctly interpret your results and make a proper diagnosis.

4. Who can diagnose ASD in adults?

If you suspect ASD, you should talk to your primary care provider. Your doctor can refer you to a behavior health specialist, such as a licensed psychologist, who is authorized to complete psychological testing. It's important to find a health care provider with specific knowledge of the ASD developmental disabilities and evaluation methods suited for adults, as they are different than those for children or adolescents. (Some clinicians with experience evaluating children and adolescents may not have experience evaluating adults.)

5. Is an autism diagnosis covered by insurance?

Although ASD evaluations are increasingly recognized as medical necessities, insurance coverage often differs among providers. Check with your insurance provider to see what they will cover. 

The bottom line: ASD can manifest differently and is often a life-long condition, but early diagnosis and treatment can make a significant difference.