New Study Suggests Four Distinct Subtypes Of Autism

Autism diagnoses are becoming more prevalent in the United States. An April report from the Centers for Disease Control and Prevention (CDC) found that approximately one in 31 children (approximately 3%) were diagnosed with autism in 2022, up from one in 36 two years prior. The CDC notes this is due not to increased rates of autism, but rather better diagnostic tools, though there is still much about autism spectrum disorder (ASD) the scientific and medical communities do not understand.

But new research out of Princeton University and the Simmons Foundation has identified four clinically and biologically distinct subtypes of autism, which they hope will lead to better understanding and more personalized care.

The study, published in Nature Genetics, analyzed data from 5,000 children in SPARK, an autism research study funded by the Simmons Foundation. Comprising of more than 380,000 participants with ASD, the study takes information and genetic material (generally saliva samples) in hopes of identifying the causes of autism to inform and establish better therapies and support for autistic individuals and families.

According to a press release from Princeton’s Office of Engineering Communications, researchers used a computational model to group individuals based on various traits in a “person-centered” approach that considered genetics and more than 230 traits — from developmental milestones to social interactions.

The study defines four subtypes of autism based on behaviors, medical diagnoses, and genetic patterns and variations. They are...

• The Social and Behavioral Challenges Group: The most common they found (about 37% of participants) — demonstrate behaviors commonly associated with autism, such as social challenges and repetitive behaviors and often have other conditions like ADHD, depression, anxiety, and/or OCD. They also tend to reach developmental milestones as expected among folks who do not have autism.
• The Moderate Challenges Group: The second most prevalent (34%) show core autism-related behaviors (stimming, social challenges), but less so than the previously listed group. They also tend to reach milestones “on time” and do not usually have co-existing psychiatric conditions.
• The Mixed ASD with Developmental Delay Group: Approximately 19% of those studied are “mixed” in that some experience repetitive behaviors and social challenges and some don’t. They tend to reach developmental milestones later than peers without an ASD diagnosis, but generally don’t have co-existing psychiatric disorders.
• The Broadly Affected Group: Just 10% of participants were found to face extreme, various challenges, from developmental delays and difficulty communicating to mood disorders.

By linking sets of behaviors and presentation of ASD with particular genetic commonalities and mutations, researchers believe this study represents a better way to understand — and establish best care practices for — people with autism. They also note this research is preliminary: there could be far more subtypes of autism that can further hone in on improved clinical practices and more bespoke care.