There is a mold that can effect flour and cause this. I think there was a book it. I believe it was documented as a cause of a whole town in Europe doing this.
http://www.dailymail.co.uk/news/article-1258801/Was-idyllic-French-village-driven-crazy-LSD-secret-American-mind-experiment.html
Think the title was The Day of Saint Anthony’s Fire. Written by the same author who wrote the story of Betty and Barney Hill.