It is important to acknowledge that loss of label does happen in autism, although not very frequently. For example, Szatmari et al. (1989) found that 25% of "nonretarded autistic children" had a very good long-term outcome and could be considered recovered. Note that the study was published in 1989, before ABA was available, and before any of the modern biomedical interventions became popular. Note also that in California, about 60% of all autistics (of all ages) registered with CDDS are "nonretarded". (Clients of CDDS classified as having autism are not supposed to be PDD-NOS or Asperger, but maybe some are). Therefore, we should expect that at least 15% of all California autistic children currently in the system will eventually be considered recovered.
That's a lot of children. And certainly these days most of them will have undergone some kind of intervention. It is not surprising then to hear of many anecdotes of children who have recovered thanks to some intervention.
My favorite case in point is Secretin. There was a Dateline show back in 1998 that told the story of Parker Beck, who was believed to have improved substantially after receiving a small amount of Secretin. I will quote a passage from the segment.
"In my book, Victoria Beck is a veritable hero," says Dr. Woody McGinnis, a general practitioner from Phoenix, Arizona. He was one of the first doctors to take Victoria and her discovery seriously. He now specializes in treating autistic children. He says that in his medical opinion, it's possible that a mother in New Hampshire has discovered a miracle treatment, maybe even a cure.
Dr. Bernard Rimland was one of the most enthusiastic promoters of Secretin as an autism treatment. I will quote him below.
Efforts are underway to increase the supply. The good news is that confirmatory evidence of the power of secretin keeps coming. A national newspaper told of Florida paediatrician Jeff Bradstreet's own four-year-old son, Matthew, shocking his parents by holding his first normal conversation with them the day after his first secretin infusion. And Virginia paediatrician Lawrence Leichtman told me of his "miracle case:" a five-year-old who had previously said only two words amazed all in the office by saying, 15 minutes after his infusion, "I am hungry. I want to eat." Most cases are much less dramatic, but the autism world is excited, and for good reason... The use of secretin appears to be the most promising treatment yet discovered for the treatment of autism... Judging from what we hear from physicians who have infused many cases (not from our SOS data) at least 75% (!) of their patients on the autistic spectrum show benefits from secretin, but we cannot yet identify a subgroup that does notably better or worse than the total group...
So what happened to Secretin? Many double-blind studies were done, as they should, and they consistently found no benefit from Secretin compared to placebo. In fact, some studies appeared to show a non-significant negative effect. The studies also documented for the first time how strong placebo effects are in autism. While some biomed researchers such as Bradstreet (and perhaps Dr. Rimland himself) still believe it is useful as an autism treatment, Secretin has fallen out of favor almost completely.
Research should go on, of course. But I suggest expectations should be managed, and claims of recovery rates should only be made after the double-blind placebo-controlled studies (preferably with independent replications) come back with results. As George Santayana says, "Those who cannot learn from history are doomed to repeat it."