The characteristics associated with asd and add are so different that an umbrella label doesn't bear relation to how they may respond to particular types of stimulus at all
Neurodivergent has been traced back to Judy Singer in the late 1990s. It refers to people whose brains have particular neurological responses with respect to remembering facts and patterns, as well as explicit cognitive focus. It was introduced primarily to distinguish between developmental disorders (which need treatment), and developmental differences (which simply need certain types of accommodation)
Yep, it looks different for everyone. And from the perspective of “does it explain or describe the person in front of me”? I agree with you - it’s about as helpful as knowing whether or not they’ve had their appendix out!
But in much the same way as fight/flight responses
look different (in fact, opposite), the neurology, what’s
actually going on in the brain, falls on a specific spectrum that is a variation of what is typically considered normal.
Like the dissociative spectrum, which ranges from normal daydreaming, to multiple personalities, it’s helpful for understanding only a very specific, neurological phenomenon. People who ‘fall on the dissociative spectrum’ experience that dissociation in vastly different ways, and from the outside, that can vary from seemingly totally normal, to flat out craycray (and not even a consistent
type of craycray!).
Neurodivergence, as a term, seeks to recognise this divergence from the normal, and help the community (particularly mental health professionals and educational institutions, but also as broadly as the local supermarket) accommodate these differences that are occurring for people on that spectrum, without reference to the thing as necessarily ‘disordered’. Different, neurodivergent, rather than disordered.
Although the term may be used in a disparaging way by some people (such is the way with so many things relating to mental health), usually through lack of awareness of what it actually means, it
has been quite successfully used to aid the development of methods that simply accommodate these neurological differences in response to stimulus, rather than perceiving people on that spectrum as having a mental health
disorder that requires treatment and recovery.