No, but then I've no evidence of its success either. Some people get better, some people get worse, some people show no change, but it's difficult to attribute any of that to the treatments that are administered. *shrugs* Then again, it was never an area of interest for me when I was studying, and that was thirty years ago [by today's date, not by Sirius' actual age {which he is sensitive about, but that can be for another thread:D }]. It's likely there have been some advances since then.
*frowns slightly* I would be... very surprised if the cause were known. *goes with it* But all right. What was the cause, what are the apparent symptoms, how was it diagnosed, and when?