First, I took Ritalin and then this happened. Ergo, Ritalin caused it . Next stop, the talk show circuit. And no matter how many long-term studies are done that find nothing spectacularly wrong with Ritalin, there will always be the possibility that the next one will find something horrible. They have anecdotes and that's enough for the media, the lawyers, the talk show hosts and their audiences.
Anecdotes are sufficient to get the government involved as well.
Republican Congressman Henry Hyde of Illinois is riding this one. It seems that the hype and near-hysteria surrounding the use of Ritalin has contributed to an atmosphere that makes it possible for a book like Indigo Children to be taken seriously. The whole situation reminds me of a poster I once saw on a bulletin board at Sacramento City College.