In his June 2010 column SRV News & Reviews (in the SRV Journal), Dr. Wolfensberger writes:
We suggest that readers give some thought to the difference between saying that somebody “has X” versus that somebody “is X,” as perhaps in “he has autism” versus “he is autistic,” or “she has dyslexia” or “is dyslexic.” “Has” subtly implies the presence of a disease or medical diagnosis; “is” seems more descriptive. “Has” also implies the need for others to “intervene,” which is much less implied in “is.” Compare these phrases: “So-and-so has stinginess” versus “so-and-so is stingy.” Perhaps someone would like to write a lengthy analysis of this issue for this Journal.
OK, there is your challenge. Now start researching and writing!