What Is Regression in Autism Spectrum Disorder (ASD)?

Autism spectrum disorder (ASD) is a neurodevelopmental condition that affects communication, social interaction, and behavior. Today, about 1 in 31 children is diagnosed with autism.¹ While many children make steady progress with early intervention, some may go through a period called regression. Understanding autism regression helps parents, caregivers, and educators know how to support children when this happens.

What is developmental regression?

Developmental regression means a child loses skills they once had. For example, a child who was using single words may stop speaking, or a child who was making eye contact and using gestures may no longer do so. Loss of previous skills can be an early sign of autism, but it can happen in children who are already diagnosed with autism and receiving treatment.

Signs of autism regression

Regression can affect many areas of a child's development, including social skills, motor abilities, daily living skills, language, or a mix of these. However, research shows that language is the most common area where autistic children experience regression, such as losing words or phrases they had already learned.²

Regression can look different for every child, but there are some common signs families may notice:

• Loss of speech or language skills: A child may stop using words they had before or go back to simpler speech. Some children may become nonverbal.
• Decline in social interaction: Children may withdraw from others, avoid eye contact, or no longer respond to their name.
• Increased repetitive behaviors: Behaviors such as hand-flapping, rocking, or repeating certain actions may become more frequent.
• Decreased motor skills: A child may struggle with skills they had before, like feeding themselves or using their hands in play.
• New or stronger sensory sensitivities: Children may develop sensitivities to sound, light, textures, or other sensory input.

How common is regression in autism?

Research shows that regression is fairly common in autistic children, though the numbers vary depending on how it’s defined and measured. Some studies suggest that about 1 in 5 children diagnosed with autism experience some form of regression.³ By comparison, regression is much less common in children without autism, with one study finding it in only about 2% of children.⁴

Regression most often begins between 15 and 30 months of age, but some children regress later in preschool or even during the early school years.⁵ While regression can feel alarming, there is hopeful news: research shows that many children regain skills over time. In fact, some studies suggest that about 43% of children regained the abilities they lost after an average of 19 months.⁴

Experts recommend that all autistic children, especially those showing signs of regression, receive thorough follow-up assessments by medical professionals. This can help identify medical or neurological conditions that may contribute to regression, some of which may be treatable.

What causes regression in autism?

Regression in children diagnosed with autism is complex and doesn’t have a single cause. Instead, researchers believe it’s often the result of a mix of factors that affect a child’s development. Importantly, studies show that regression is not linked to family characteristics. Things like socioeconomic status, ethnicity, birth order, pregnancy or birth complications, gender, or the age a child is diagnosed are not associated with whether a child experiences regression.⁶

While every child’s story is unique, scientists are studying several areas that may play a role in regression. These include genetics, brain development, stress and environmental changes, medical issues, and co-occurring mental health conditions.

Genetic factors

Research shows that genetics may play a role in regression. In one recent study of 134 children with autism and regression, scientists found specific genetic variants that may be linked to skill loss. Experts believe this is just the beginning of using genetic research to better understand why regression happens and how biological processes may contribute.⁷

Environmental stressors

Stressful events or big changes in a child’s environment may also trigger regression. Because many children with autism experience sensory sensitivities, shifts in routine, such as moving homes, starting a new school, or even changes in daily structure, can cause overwhelming stress. Research shows that chronic stress or sensory overload could lead to setbacks or loss of skills due to heightened anxiety.⁸ 

Brain & medical issues

Certain health conditions may also contribute to regression. Epilepsy, in particular, has been strongly linked to regression, with one study finding that epilepsy is 59% more common in children with autism who regress compared to those who do not. Other medical factors, like gastrointestinal problems or sensory processing challenges, might also affect development and may play a role in skill loss.⁷ 

Studies also point to other neurological conditions as possible contributors. For example, mitochondrial dysfunction, a condition that affects how cells produce energy, may impact brain function in children with autism and play a role in regression.⁹

Mental health conditions

Many children diagnosed with autism also experience conditions such as attention-deficit/hyperactivity disorder (ADHD), anxiety, or depression. These conditions can make autism symptoms harder to manage and may contribute to regression. Research suggests that addressing these conditions with the right supports and treatments can help prevent further developmental delays.⁷

Regressive autism and parent stress

When a child suddenly loses skills, parents can feel overwhelmed and concerned. Research shows that parents of children who experience regression often report higher stress, fewer support systems, and more uncertainty about their child’s future.⁷

At the same time, research from Action Behavior Centers (ABC) shows that support and applied behavior analysis therapy can help reduce this stress. In a review of nearly 300 families, overall stress levels dropped in the first year of treatment, with the greatest improvements in families who started out with the highest stress.¹⁰

Learn more: ABA Therapy Outcomes & Family Impact Stories

How can parents help children with autism regression?

If your autistic child is experiencing regression, it’s important to remember that there is hope. With the right support, many children regain lost skills and continue to reach milestone moments. Here are some ways parents can help:

• Consult with a specialist: Talk with your child’s pediatrician or an autism specialist to rule out medical concerns and get a thorough evaluation.
• Focus on early intervention: Start or continue therapies such as applied behavior analysis (ABA) therapy, speech therapy, or occupational therapy. Early intervention gives children the best chance to rebuild skills and make progress. 
• Maintain consistency and routine: Children diagnosed with autism often feel more secure with predictable schedules. Keeping daily routines steady and preparing your child for changes in advance can reduce anxiety and support learning.

Regressive autism and Action Behavior Centers

Regression can feel overwhelming for parents and caregivers, but it's important to know that it's a common part of many autistic children's journeys. With the right support, many children regain lost skills and continue to grow.

If you're noticing changes in your child but aren't sure what they mean, you don't have to figure it out alone. Action Behavior Centers offers quick online autism screeners to help you understand your next steps, along with professional autism evaluations, and center-based ABA therapy with no waitlists. Our ABA therapy centers are available in cities like Phoenix, Philadelphia, and Houston. To get started today, find an ABA therapy center near you.

Helpful resource: Autism regression checklist for parents

If you’re concerned that your child may be experiencing regression, this checklist can help you track changes. You can share it with your pediatrician or your child’s Board Certified Behavior Analyst® (BCBA®):

• Has your child stopped using words or phrases they previously used?
• Are they having difficulty forming sentences?
• Is your child pulling away from family members or peers?
• Are they avoiding eye contact or not responding to their name?
• Have repetitive behaviors, like hand-flapping, rocking, or spinning objects, increased?
• Have you noticed a decline in your child’s motor skills, such as trouble eating, walking, or using their hands during play?
• Is your child becoming more frustrated, irritable, or aggressive?
• Are tantrums happening more often or with greater intensity?
• Has your child become more sensitive to sensory input, like lights, sounds, or textures
• Is your child losing interest in activities or play that they once enjoyed?
• Are they struggling with tasks they once did independently, like dressing or feeding themselves?

If you answered “yes” to any of these, it’s a good idea to talk to your child’s BCBA or reach out to a pediatrician or autism specialist for recommendations.