They probably experience a lot more brain trauma to the point I’m a little wary of assuming they have the same condition as autistics - the etiology might be totally different with a similar symptomology which is the sort of situation the DSM is ill equipped to distinguish between.
The ICD even has the separate concept of CPTSD which imho might fit autistics better.
Stimming helps autistic people. Refraining from stimming leads to increased anxiety in autism [1].
It can very well be the case that it does not help any allistic people, I'm not familiar with the literature in that regard. Searching for "stimming PTSD" in google scholar does not bring up any studies that look into this, so if PTSD and ASD share some common characteristics this might be worthwhile looking into.
“Senior author Dr Nathalie Dehorter said the study —
conducted on mice…”