When that trait interferes with your daily life. It's pretty common for people to be afraid of heights but if that fear interferes with getting a job, having relationships, enjoying everyday activities, then that's a disorder.
The problem is lay people think of "autism" the way that creationists say evolution is a "theory". An awkward introvert with technical interests isn't going to be professionally diagnosed as autistic unless they have some pretty serious and defined symptoms. But that doesn't stop misinformed lay-person usage in everyday conversation.
My issue with that attempt to define a disorder is that it can medicalize mismatches with artificial environments. (That is, almost all environments humans live in.) It in effect defines all deviations from "normal" as defects.
Imagine you're living in a culture of subsistence agriculture. And imagine further that you are thin, quiet, nearsighted, physically delicate, and are inclined to spend all your time reading. You are basically unsuited for the available jobs, nobody wants you in a relationship, and what everyday activities are available are ones you don't enjoy. So the village headman decides that you have a disorder and need treatment, by which he means regular beatings. Of course, you might make a fine librarian, but that's not an option.
The same thing was done with gay people for ages. Or women; note how female hysteria was a medical diagnosis that eventually vanished: http://en.wikipedia.org/wiki/Female_hysteria
As another example, quite a lot of American children end up medicated because they are inconvenient for overworked teachers in classrooms that follow industrial models of education. A friend of mine was once a substitute teacher in a class where every single student had been diagnosed with ADHD and was on medication. The daily life that their trait was interfering with is entirely artificial. At some point I think one has to wonder whether the problem is the trait or the constructed environment that the trait isn't a good match for.
I work in a Sudbury school where we have two kids diagnosed with autism. When they first arrived, they had some problems. But in the free environment of our school, they have become as amazing as all the other children in the school. I don't even think of them as being autistic.
We all have deficiencies. What we all need are environments that let us figure out how to cope with them.
Of course, it is all matters of degree and people need to be able to take responsibility for their actions and needs. Not all can and that requires something different.
It should be noted that in kids nobody can say whether it will _always_ interfere with their daily life in a material way. Autism diagnosis in a preschooler usually (90%-ish?) means it will, which is amazingly accurate if you think about it. But it's definitely not 100%. So in little kids, the diagnostician is saying they _think_ it will interfere with daily life (and that it is interfering today, but saying that about a 3-year-old doesn't necessarily mean always and forever).
Another issue is that it's sometimes easier to have a personal difference interfere with school than it is to have it interfere with real life. That argument is at http://intellectualizing.net/2015/03/12/schools-are-disorder...
Real life is more flexible than most schools.
Personally, colorblindness is my go-to example here, because it is similarly spectrum-ish (and not in the punny sense).
We use the term "colorblindness" in a monolithic way, yet it refers to any of at least eight different things, each of which is caused by a different genetic mutation and produces a different physiologic result. Even the term "red-green colorblindness" is misleading, because it could refer to at least four different things.
Many people with "colorblindness" can actually live their whole lives without ever realizing it; the most common form (deuteranomaly, which is what most people mean by "red-green colorblindness", despite it actually affecting the yellow-orange-brown area of the visible spectrum) rarely if ever interferes with common day-to-day life for many people who have it (like me). On the other hand, the rarer forms can significantly impair vision to the point that common tasks become difficult or even impossible. Yet most of the time we use the same term, "colorblindness", to refer to all of them.
In much the same way, "autism" refers to a wide range of situations, some of which have significant effects on day-to-day life and some of which have much lesser effects.
> You're missing his point. At what point does a personality trait become a disorder?
In the case of my nephew, his condition (his pediatrician diagnosing him to have Autism) became a disorder when it was proven that his symptoms were the result of numerous factors, all resolved under a licensed doctor's care using standard blood and stool tests to detect, and standard biomedical interventions to correct. He suffered from numerous food allergies, a raging yeast infection, and heavy metal poisoning.
His issues arose mostly as the result of his body's deficiency in creating glutathione, an essential antioxidant produced by our bodies to aid in the excretion of toxins. This deficiency was confirmed by genetic sequencing that revealed an MTHFR mutation, passed on to him by both parents, therefore a double mutation, limiting his glutathione production to 7-10% of normal.
His symptoms started at about 2-1/2. At the age of 7 or so, his doctors diagnosed him as "indistinguishable from his peers", after the interventions and much developmental therapy to help him catch up. He eats a rotating diet, where the same food does not repeat for several days at a time, and takes numerous supplements to address deficiencies revealed by the aforementioned blood and stool samples.
The only lingering sign of autism we can notice is he still loves some good bear hugs. I'm happy to oblige him.
