On the neurodivergent majority

Today marks the three-year anniversary of my autism diagnosis, the day I was officially told that my brain works differently - just like everyone else’s. While it is true that only approximately 1.7% of Americans are autistic and share that particular pattern of neurological difference, the reality is that everyone’s brain works uniquely (including variance among individuals on the spectrum). This is the concept of neurodiversity.

Defining Neurodiversity

Neurodiversity is Human Diversity

The term neurodiversity was coined by sociologist Judy Singer in 1996. At its simplest, it means neurological diversity, as biodiversity means biological diversity. It is the full range of differences in human brains and minds. We are all neurodiverse, because everyone’s nervous system is unique, and due to different genetics and life experiences no two people think exactly the same way. 

Within the realm of neurodiversity, there are distinctions made between people who are “neurotypical” and “neurodivergent.” To be neurodivergent is to have a brain that functions in a way that diverges significantly from the dominant societal standards of “normal,” as advocate Nick Walker explains on their well-circulated blog post, “Neurodiversity: Some Basic Terms and Definitions.” The term is used most often to refer to people who have a diagnosis of autism or attention-deficit-hyperactive-disorder (ADHD), but it includes many other conditions including but not limited to bipolar, dyslexia, schizophrenia, synesthesia, and post-traumatic-stress-disorder (PTSD). Many of these conditions are genetic and present from childhood, while others, such as PTSD, are acquired differences in the nervous system/brain. I include the trait of high sensitivity as a form of neurodivergence, because while it is not a diagnosable condition it is an innate difference in neurological processing of the environment.

The neurodiversity movement is an advocacy movement that recognizes that people with different kinds of minds are often oppressed by a society that is not accepting of these differences. It is part of disability advocacy movements and as such recognizes that many forms of neurodivergence are disabilities, either medically or socially, or both. There is an understanding in the movement of the importance of having minds which work differently for society at large and a recognition that innovation often comes from people who see and understand from a unique perspective. Because the movement takes a non-pathologizing view of cognitive differences, some consider it controversial, but it has gained mainstream traction in recent years. The symbol of the neurodiversity movement is a rainbow infinity symbol. 

Determining Prevalence of Neurodivergence

Conservative US prevalence estimates:

Neurodivergent 67.2%

Neurotypical 32.8%

The National Institute of Health (NIH), which studies epidemiology (health on a population level), defines prevalence as the portion of the population who has a specific characteristic or condition in a given time period. It is challenging to determine how much of the United States population has a neurodivergent experience because many of these conditions are diagnosed at different life stages, and some are not officially diagnosed at all. Some physicians believe these conditions are specific to children, some believe they can be cured, others suggest that the presentations change over the course of development but that they are lifelong differences. For this graphic representation of neurodivergence in the US population, I have taken the latter view – that the most accurate representation of the prevalence of neurodivergence is a lifetime prevalence, as most of these conditions may change in presentation or in symptom severity, but the underlying difference is part of the person’s neurology and is therefore lifelong.

The CDC has estimates for the prevalence of autism in children, but not in adults or across the population. These rates have increased slightly in recent years due to improved diagnosis of autism, particularly in females, but remain around 1.7%. Similarly, ADHD is more frequently diagnosed in children and has lower rates in adults, but across the population the CDC estimates 9.4% of Americans have the condition. The lifestyle prevalence of bipolar disorder is estimated to be 4.4%, schizophrenia 0.5%, and PTSD 6.8%. Other estimates include 15% dyslexia, 5% sensory processing disorder, and 4.4% synesthesia. Researcher and clinical psychologist Elaine Aron has estimated a prevalence of 20% of the population has the trait of high sensitivity.  When these prevalences are combined, the neurodivergent among us outnumber the neurotypical, which raises the question of whether there is a “typical” to begin with, or rather a collection of different patterns of experience across humanity.

“Based on estimates of lifetime prevalence, neurotypicals comprise only 32.8% of the US population. It is likely that “neurotypical” people are, in fact, the minority. ”

*Note that there is also likely overlap between these forms of neurodivergence, as one person can have multiple conditions. ADHD and autism frequently co-occur, for example, and many people on the autism spectrum would identify as highly sensitive.