Marina Sarris

Date Published: March 12, 2025

You or your child has been diagnosed with autism spectrum disorder, and you have questions. We at the SPARK autism study have some answers, based on published scientific research.

What is autism?

Autism is a developmental condition with signs that are present in early childhood. Doctors can diagnose it by age 2, although children in the United States are diagnosed at an average age of 4.

To receive an autism diagnosis, people need to have two features. The first one is having differences in how they communicate and interact with others. Delayed or limited speech is often an early sign of autism. Many autistic people have no history of speech delay, although they may speak or use language in unusual ways.

Autistic people may find it difficult to have a two-way conversation or to know what to do in social situations.

Autism affects nonverbal communication, too. Children may not point or gesture, for instance, and adults may find it hard to tell by someone’s body language and facial expression if they are happy or angry.

The second autism feature is having repetitive and restrictive behaviors. These behaviors include:

• Repetitive movements or sounds, such as spinning in circles, rocking, flicking fingers in front of the eyes, grunting, or saying a phrase over and over.
• Insisting that routines, meals, or surroundings be the same every day.
• An intense, narrow (or “restricted”) interest. People may be described as obsessed with videos or TV, animals, objects such as trains or cars, science, music, or other subjects.
• Over- or under-responding to one’s senses of sight, sound, smell, or touch.

What does it mean to have Level 1, 2, or 3 autism?

The autism “spectrum” refers to the wide differences in how autism affects people. Some people may not speak, for example, while others talk fluently. Doctors may assign a “severity level” from 1 to 3 to describe where on the spectrum a person falls at that moment. The higher the number, the more support the person needs.

The severity level given to a young child at diagnosis could change as the child develops and responds to therapies and special education.

How do I find services for a child who has a new autism diagnosis, or who is waiting for one?

U.S. law guarantees children with disabilities a free, appropriate public education from birth to 21. Contact your state’s early intervention program to refer your baby or toddler for a developmental evaluation and services. If your child is aged 3 to 5, call a public elementary school near you and ask for an evaluation for preschool services. For students in kindergarten to 12^th grade, contact their public school to request an evaluation for services. You do not need to wait for an autism diagnosis to begin receiving help.

Common interventions include speech, behavioral, occupational, and physical therapies, along with special education. Early intervention and school teams will develop a plan with learning goals designed for your child, along with the services needed to meet those goals. School-aged children can also get accommodations, such as audiobooks and extra time to take tests.

Parents and guardians are members of the school team and can influence its decisions. See SPARK articles and webinars about school advocacy to learn more.

How does an adult who was just diagnosed with autism find services?

Contact your state’s developmental disabilities agency to learn about housing, day programs, personal supports, and employment help for which you may qualify.

Be aware that the adult disability service system is different than the one for children and youth. People who have finished high school are not guaranteed to receive disability services. Many states have waiting lists due to a shortage of funds. They often serve those with the most significant needs first.

Also, contact your state vocational rehabilitation agency for help with job training and your job search.

If you’re a college student with an autism diagnosis, go to your school’s office of disability support services to register for accommodations that you need.

Can I get accommodations for autism at work?

Yes, if your employer has at least 15 employees. U.S. law protects employees with disabilities from discrimination and allows them to request accommodations, such as written instructions or a quieter workspace. To be eligible, the employee must be qualified and able to perform “basic job duties” either “with or without reasonable accommodation,” according to the U.S. Equal Employment Opportunity Commission. An accommodation is considered reasonable if it does not place an “undue hardship” on the employer. Visit the Job Accommodation Network of the U.S. Department of Labor to learn more.

Does autism affect girls and boys equally?

No, autistic people assigned male at birth outnumber those assigned female at birth by almost 4 to 1. Males may be more likely to have autism for genetic reasons. Researchers also suspect that some autistic girls and women are going undiagnosed because they have different traits and coping skills.

What causes autism?

Research shows that our genes and certain environmental exposures likely contribute to autism.

Genetic factors: Scientists have found variations in more than 400 genes and parts of chromosomes that cause autism.

The SPARK study examines the DNA of participants who give saliva samples. The study has found genetic variations that cause autism in about 10 percent of its participants. SPARK lets people know about their variant, if they want to be told.

Most of the variations that SPARK has found were not inherited from parents. Instead, they occurred by chance in the child in the womb. Learn more about autism genetics at SPARK.

Environmental factors: Research studies have found that some factors that occur during pregnancy and birth may increase the chances of a child having autism.^1,2

These environmental factors include a very premature birth or low birth weight, prenatal exposure to some pesticides or air pollution, birth complications, and parents who were older in age when their baby was conceived. Your child is also more likely to have autism if you had diabetes, immune system problems, or obesity during pregnancy. “But these factors alone are unlikely to cause autism. Rather, they appear to increase a child’s risk for developing autism when combined with genetic factors,” according to the National Institute of Environmental Health Sciences.³

Do vaccines cause autism?

Multiple research studies in different countries have found no link between autism and vaccines.^4-8 To learn more, see a list of vaccine studies compiled by the Autism Science Foundation.

Why are autism diagnosis rates rising?

There are several possible reasons. One has to do with how autism is defined and diagnosed. In the mid-20^th Century, autism was considered to be a rare, severe condition. Only people with the most significant needs for support – and access to doctors knowledgeable about autism – received an autism diagnosis.⁹ Recognizing that autism is a spectrum, American psychiatrists began expanding the borders of the diagnosis in the 1980s and 1990s to include people without significant speech and learning delays.¹⁰ They modified diagnostic rules for autism again in 2013.

The changing definition of autism, and greater public awareness, likely contributed to a growth in diagnoses. Parents, teachers, and doctors became more aware of autism and its signs. In 2007, the American Academy of Pediatrics recommended that pediatricians begin routinely screening all children for autism at 18 months and 24 months of age.

Many of the 20,000 independent adults in SPARK were born before those changes took place. They are being diagnosed with autism for the first time in their 30s, 40s, and beyond. The most frequently reported age of diagnosis is 36, according to SPARK data compiled in 2024.

Researchers continue to examine genetic and environmental factors that could be contributing to the increase in diagnoses.

Are there other medical conditions I should be aware of?

People with autism are more likely than others to have certain health conditions, although these conditions are not part of autism. These conditions include ADHD, epilepsy, depression, bipolar disorder, anxiety, intellectual disability, sleep problems, and gastrointestinal and feeding problems.

Less is known about autistic adults than autistic children. However, autistic adults in SPARK have been participating in research into medical conditions that may occur with aging.

Interested in joining SPARK? Here’s what you should know.

Photo credit: iStock

References

1. Modabbernia A. et al. Mol. Autism 8, 13 (2017) PubMed
2. Lyall K. et al. Annu. Rev. Public Health 38, 81-102 (2017) PubMed
3. National Institute of Environmental Health Sciences. Autism. https://www.niehs.nih.gov/health/topics/conditions/autism. Accessed Mar. 11, 2025.
4. Taylor L.E. et al. Vaccine 32, 3623-3629 (2014) PubMed
5. Jain A. et al. JAMA 313, 1534-1540 (2015) PubMed
6. Hviid A. et al. Ann. Intern. Med. 170, 513-520 (2019) PubMed
7. Iqbal S. et al. Pharmacoepidemiol. Drug Saf. 22, 1263-1270 (2013) PubMed
8. Heron J. et al. Pediatrics 114, 577-583 (2004) PubMed
9. Shapiro B. and P. Accardo Preface. Autism frontiers: Clinical issues and innovations (pp. xi-xiii). Newburyport: Brookes Publishing (2014)
10. Donvan J. and C. Zucker In a different key: The story of autism (1st ed.). New York: Crown Publishers (2016)