Opinion: government workers label things mass hysteria when they have to file reports but cant keep those blank. Tangentially, also in the "toxic lady" case where 5 people were hospitalixed (1 for 2 weeks in ICU), since reasonable explanation werent found, it ended up ruled as mass Histeria.

It is also surfacing that a lot of Historical Mass-Histeria episodes were linked to phisical causes such as hallucinogen contaminated bread, instead to the Devil for the ancients or Self-delusions for the Modern people