Neuroscience is absolutely in its infancy. It is centuries behind chemistry and biology and physics. A lot of what we think we know about neurodiversity is probably going to be shown to be completely wrong in the coming decades.
Autism and ADHD, in that they have been studied at all, have been looked at through the lenses of the medical-deficit model and with the diagnostic perspective of how they might appear in white, middle-class, elementary boys in a Western, industrialist, colonialist, patriarchal culture, which coincidentally, is the culture of psychology. Western researchers are just beginning to realize that what autism and ADHD might look like is much broader and more diverse than previously understood.
No one knows precisely what genes are behind these neurotypes, but it is clear that they are genetic due to how they travel in families. Prior to the DSM-V, it was not acknowledged that these two different brain styles could occur in the same person, but now researchers believe that between 20 and 60 percent of autistic people also have ADHD. From the lived experiences I have read of people with both, sometimes the two interact in such a way as to make signs of neurodivergency more obvious, and sometimes they sort of cancel each other out, making signs of neurodivergency less obvious. ADHD and autism often co-occur in families: if you have an autistic sibling, you have a higher chance of autism and of ADHD yourself.
To be clear, autism and ADHD, among a whole set of hereditary neurodivergencies, are not mental illnesses, but more like being left-handed in a right-handed world. It's a genetic and less-common option. The medical-deficit model really falls down, as these are not medical conditions, nor do people grow out of them, nor are they "curable". Autistic and ADHD people continue to grow and change and learn throughout their lives, just as neurotypical people do. The social-disability model provides a framework for seeing that many of the true challenges faced by people with neurodivergent brains are caused by not fitting into the dominant culture, created over time, largely by decisions of neurotypical people, and in the West, by a patriarchal, racist, colonialist, conformist, "progress"-driven culture. This even boils down to how we perceived parent-child relationships should look and our grand 100-year-old experiment with public school for all, and often these conventions are not a solid fit for neurodivergent children.
A few words about the DSM-V...
First of all, the DSM is designed to describe mental disorders, and in the past has included homosexuality. Of course, now homosexuality is not understood as mental or disorder, and I think that autism may some day wind up no longer being classified this way either. I hope....
Autism is a synthesis of three previous diagnoses: Kanner's syndrome (which is the stereotyped non-speaking, repetitive movement flavor, assumed in the past to always co-occur with intellectual disability), Asperger's syndrome (which is stereotypically associated with obsessions in the areas of math, science, and technology, sometimes resulting in prodigious abilities, paired with social awkwardness/gaffes - the whole absentminded professor trope), and PDD-NOS (pervasive developmental disorder not otherwise specified, often given to a child developing typically who has suddenly lost skills, such as the ability to communicate through verbal language.) All of these are now seen as flavors of the same thing, and the DSM -V supplements the ASD diagnosis with levels 1, 2, and 3 to denote the amount of support that individual needs. There is some consternation over support levels in the autistic community, as the numbers are assigned by an outside observer who has known you for only a few days at best. Support needs can vary dramatically over time; those listed as level 1 who are considered "high-functioning" or "almost normal" can have very high hidden support needs. Also level 3 is sometimes used to write off people as less intelligent or valuable. Researchers are discovering that while some autistic people do have severe intellectual disabilities, many non-speaking autistics actually have an immense grasp of language and either don't have the physical coordination to pull off talking or there is an emotional block between the words in their mind and their body's ability to spit them out. This is especially true for typically verbal people who occasionally have mute episodes. There is a whole field of AAC opening up the windows of communication for those who cannot, either occasionally, or always, use mouth words.
The DSM, in addition to having a list of traits for autism, specifies that those traits must impact the autistic person's life at a certain level, which is again subjective, and may differ greatly at different points in a person's life. This leads to a group of fairly "functional" people who could be said to have a sub-clinical presentation or be part of the "greater autism phenotype". The DSM-V has included a new diagnosis for those who miss the cut-off in terms of numbers of points assigned by the clinician for "proper autism" in a given week: social pragmatic communication disorder, aka "autism lite."
No one knows what creates the vast spectrum of different shades and flavors of autism, but it is estimated that between 2 and 5 percent of the world's population have this sort of brain, again, not evenly distributed, as it runs in families. Many, many adults are now learning more about autism and realizing it applies to them, and many, many of them are finding relief in that understanding. It's an aha! moment: "This explains why I never fit in. This explains why I felt like everyone else had a blueprint for life that I could never find." Many adults are discovering this identity for themselves after their children are diagnosed. Conversely, some adults do not see their own autism or the autism of of their loved ones, due to perceptions of autism as a negative mental issue or a medical problem or due to common misperceptions like "Autism means lack of eye contact," or "Autism means you don't know how to tell jokes," or "Autism means you are into math," or "Autism means you can't talk." As a culture we have a lot of internalized ableism around neurodivergence. Many autistic females are either unidentified or wrongly diagnosed with bipolar, borderline personality disorder, or merely with anxiety or depression. There are also many unidentified autistic people around who have no idea that they are and couldn't care less, and that is, of course, perfectly fine.
There has been panic from some quarters that the amount of autism is rising, and this is often paired with a search for a "cure" and invasive, traumatic neuronormative "conversion" therapies. From what I understand, a rise in autism is not likely. What is more likely is that autistic minds have been with us for a very long time and we are getting better at identifying and understanding them. Some famous male cultural icons in the West who it is believed would likely be identified as autistic today include Ludwig van Beethoven, Wolfgang Amadeus Mozart, George Washington, Charles Darwin, and Albert Einstein. This is not to say all autistic people are brilliant. There is the full range of intellectual ability present on the autism spectrum, and many autistic people find themselves barely able to cope in their cultural situations.
DSM language around autism is, in fact, quite negative. Words like "deficits" and "symptoms" abound. Many prefer to think of "traits" instead.... Here are a few re-language-ing options:
*Different priorities in focus and social communication from neurotypical minds
*Internal or external discomfort with neurotypical emotional expression
*Deep interest or attention surrounding details and patterns
*Inner need to create patterns or rituals
*Long-term deep interests in topics or objects
*Possible high intensity and/or low intensity of physical senses
These traits are life-long but can look dramatically different in various stages of life.
Here's the place for a word about "masking". Most humans do this on some level - changing our outward behavior from what feels natural at various levels to fit the circumstance. This can be things like having a certain persona or tone at work, then relaxing at home. Or it could be taking on the accent or grammar of the person you are speaking with. It could be swaggering and swearing when you're out with "the guys". Some autistic people learn to mask their quirks such that they are not easily detectable by society around them. Others do not, or cannot, and they are often the ones who are seen as "less than". Some masking is natural, some might be fun, some might be painful. In the last category, imagine a person with very sensitive ears who goes into a store with loud music, and the music makes it very difficult for that person to think well enough to find what they are looking for. They feel like screaming and covering their ears at the auditory assault, but instead they grin and bear it, saving their big reaction for a private place or perhaps internalizing it and perhaps questioning their sanity. Masking plays a large and burdensome role in some autistic people's lives, but on the other extreme, some people don't do any and are sort of "unfiltered", and some enjoy the mental gymnastics of being a chameleon and "channeling " various personae.
ADHD in the DSM-V is a combination of two previous diagnoses: ADHD and ADD. Again, the diagnostic criteria are skewed toward the white, middle-class, elementary-aged males, leaving many people, especially females, unidentified. There are a number of overlaps between autism and ADHD, making it easy for clinicians to see the ADHD and overlook the autism (or visa versa) when they occur in the same person. The criteria for ADHD are simpler than for ASD, although it can impact a wide number of areas in life. There are three diagnosable types: hyperactive, which refers to a body (and sometime speaking) that needs to be in constant motion; inattentive, which refers to a "Ferrari brain", as one adult ADHD-er affectionately described it (one that is going fast and furious, devouring and working with thoughts at a level not accessible to mere mortals, thus not lingering in one expected place for very long), and the combined type, which is both at once, and is the most common. These various traits can be dialed up or down at different levels. ADHD is often associated with creative thinking, and some famous people who could be identified now as ADHD are Abraham Lincoln, Thomas Eddison, Ansel Adams, Scott Fitzgerald, and Vincent van Gogh.
There are stereotypes and misunderstandings about ADHD. Some ADHD-ers are surrounded by chaos. Others are extremely organized to keep the chaos at bay. Some have had trouble accessing education. Others have found that their ADHD traits help them broaden their education daily. Some find it difficult to hold down a traditional job. Others have found that their ADHD makes them a perfect fit for their job. Some find that they may have trouble holding it together until there is an emergency or deadline looming, and then they are able to focus and do their best work. Many people live their lives not knowing they have an ADHD brain, some happily, and some weighed down by negative labels - "not living up to potential," "distracted," "naughty."
The DSM-V, again, uses very negative language to describe traits: "difficulty" with *insert Western cultural expectation*.
There is a lot of new learning about brain response in the area of polyvagal theory and more holistic understandings of behavior as communication of what is going on inside, which makes the future look a bit brighter for neurodivergent people as they navigate their own path through a sometimes uncomfortable or hostile system and environment. I can't help but think over and again how these kinds of brains might manifest with a whole different set of strengths and weaknesses in a more traditional hunter-gatherer society.
While some people wish their neurodivergency away, or at least balk at the challenges that come with being a "lefty" in a right-handed world, many, many autistic and ADHD adults rather like the quirks and strengths of their brains and wouldn't want to be any other way.
Here are some different opinions:
https://jessemeadows.medium.com/youre-using-the-word-neurodiversity-wrong-e579ffa816a8
Why the neurodiversity movement has become harmful | Aeon Essays
