Yes: over the past 12 years, rates of autism spectrum disorders (ASD) have increased in prevalence both overall and in several demographic groups.
In a new study published in the Journal of the American Medical Association (JAMA), “Autism Diagnosis Among US Children and Adults, 2011-2022,” a group of researchers analyzed records collected from the Mental Health Research Network (MHRN) database, which gathers patient data from the largest health care networks in the nation.
In total, the research team used information on over 12.25 million patients collected between 2011 and 2012. Here’s a demographic breakdown of the sample set:
Age:
- Children under 18: 19.2%
- Adults 18+: 80.2%
Gender:
- Female: 52%
- Male: 48%
Race/ethnicity:
- White: 52.7%
- Hispanic: 24.2%
- Asian: 14%
- Black: 7.8% Black
- Native Hawaiian or Pacific Islander: 1.4%
- American Indian/Alaska Native: 0.8%
This large and diverse sample set allows the researchers to make population level generalizations regarding the prevalence of autism spectrum disorders in the general population. This allows parents, providers, and public policy makers to make evidence-based choices about diagnosis and support for people with autism spectrum disorder (ASD) in order to offer the most effective approaches to ASD in school, at home, and in society-at-large.
Before we report the results of the study, let’s get on the same page with exactly what we mean when we say autism spectrum disorders, and learn about the primary features of ASD.
What Are Autism Spectrum Disorders?
For decades, Diagnostic and Statistical Manual of Behavioral Disorders (DSM) divided ASD into several sub-classifications, including autism, Asperger syndrome, pervasive developmental disorder no otherwise specified, and childhood disintegrative disorder. However, with the publication of the Fifth Edition of the DSM (DSM-5), mental health experts combined these various subclassifications into one distinct diagnosis called autism spectrum disorders (ASD).
Here’s the updated definition of ASD – based on the DSM-5 reclassification – as offered by the American Psychological Association (APA):
“Autism spectrum disorders (ASD) are a group of developmental disorders with onset typically occurring during preschool. ASD are identified by varying and persistent deficits in social communication and social interaction, including difficulties with social-emotional reciprocity, nonverbal communication behaviors, and social relationships. ASD often include restricted/ repetitive patterns of interests, behaviors, and/or activities.”
To meet criteria for ASD diagnosis an individual must display elements of both primary features of ASD: problems with social communication/interaction, and restricted patterns of behavior, interest, and activity.
Problems with social communication and interaction include:
- Difficulty engaging with other people
- Difficulty sharing thoughts and feelings
- Challenges with nonverbal communication: difficulty making eye contact, understanding body language, and understanding facial expression
- Problems making, developing, and maintaining relationships
Restricted patterns of behavior/interest/activity include:
- Repetitive movements or speech
- Persistent adherence to specific routines
- Intense resistance to change in routines
- Narrow and restricted – but intense – interests
- Significantly elevated response to physical sensations such as textures, tastes, and odors
- Significantly decreased/absence of response to physical sensations such as textures, tastes, and odors
These features of ASD can prevent an individual from full participation in activities at home, at school, and in the workplace. While the features of ASD can cause significant problems, those problems have a wide range in severity. Some people with ASD integrate fully into typical social, academic, and work situations, while others with ASD experience features that prevent full integration, and require specialized support from family and/or mental health/child development experts.
Now that we’re on the same page with what ASD is and we understand the primary features, let’s review the results of the study we introduce at the beginning of this article.
Autism Spectrum Disorder: 12-Year Prevalence Trends
We’ll start with the big-picture results. After a review of patient records – over 12,25 million – the research team identified increases in ASD diagnosis over the past twelve years. Here’s the data for all age groups and demographics combined.
Diagnosis of ASD By Year Per 1,000 People: Overall Results
- 2011: 2.3
- 2012: 2.5
- 2013: 2.8
- 2014: 3.1
- 2015: 3.3
- 2016: 3.6
- 2017: 4.0
- 2018: 4.4
- 2019: 4.8
- 2020: 4.9
- 2021: 5.7
- 2022: 6.3
Those figures show an increase of 175 percent in the overall prevalence of ASD between 2011 and 2022:
- 2011: 2.3 per 1000
- 2022: 6.3 per 1000
In addition, researchers identified changes for specific demographic groups and age ranges.
Changes in Diagnosis Over Time: Autism Prevalence
- Highest yearly rates appeared among 5-to-8-year-olds:
- 2011: 9.9 per 1,000
- 2022: 30.3 per 1,000
- Largest increase – 450% – appeared among 26–34-year-olds:
- 2011: 0.7 per 1,000
- 2022: 3.7 per 1,000
- Changes by gender:
- Among children, greatest increases appeared among females:
- Females: 305%
- Males: 185%
- Among adults, greatest increases appeared among females:
- Females: 315%
- Males: 215%
- Among children, greatest increases appeared among females:
Overall, researchers identified increases for children and adults across all age, gender, race, and ethnic demographics. Among children, the research team indicates increases align with the development of improved early detection processes and the advent of universal pediatric screening. Among adults, the research team indicates increases for 18-to-25 and 26-to-34-year-olds align with recent Medicaid data, which show increases ASD diagnosis in most adult age categories.
However, these results may underestimate the actual prevalence of autism spectrum disorder among adults and among older females. Many adults – particularly females – may not have been assessed for ASD during childhood and may not receive an assessment for ASD during adulthood.
What Do These Autism Prevalence Results Mean?
For adults and young adults – despite these gaps in assessment identified above – increases were higher among females than males, a phenomenon that may be explained by an increase in awareness of ASD in females, increased representation online/social media representation for females with ASD, the development of effective assessment tools for ASD, and increased training for in ASD diagnosis among providers.
What these results mean is that we should consider increasing our default level of screening for ASD among adults, and young female adults in particular. The data show prevalence increasing each year, which means that more adults now than ever have an ASD diagnosis. Many of those adults and young adults may benefit not only from the support associated with a diagnosis, but also from an increased understanding of themselves, facilitated by their diagnosis. In some cases, adults can understand – often for the first time – the origin of their preference for specific interests, behaviors, and activities.
For children, the data show that we need to consider expanding our default assessment patterns to include females more than we have in the past. Rates of ASD increased among female children by over 300 percent. While the prevalence of ASD remains higher among male children, researchers found greater annual percentage increases for female children compared to male children: 13.62 percent for female children, and 9.63 percent for male children.
Based on this data, it’s likely we can help female children that would have previously gone undiagnosed, based on the assumption that ASD occurs more often in males than females, by increasing ASD screening among female children. While it’s true that ASD appears more often among male children, the increase in diagnosis among female children between 2011 and 2022 show we need to expand our understanding of who may develop ASD, and when.
Assessment Practices and Autism Spectrum Disorder Prevalence
The study we discuss in this article teaches us something important:
ASD is not exclusive to male children.
ASD can appear among female children and adults of any gender. That means we need to reevaluate our assessment routines to include all children and all adults. When providers can identify what’s going on, they’re in a better position to help. This study shows that there are likely more females and adults that need support for ASD than most providers previously realized. With increased assessment across all demographics, we can identify people who need our support and offer it when they’re ready.
