Though it was unclear if the recent poisonings were the result of attacks, militants in southern Afghanistan have previously assaulted schoolgirls by spraying acid in their faces and burning down schools. But with no group claiming responsibility, some officials speculated that the illnesses could be the result of group hysteria.
It's also important to note that a similar incident took place last month in which other girls were hospitalized after exposure to fumes, or possibly a poison gas cloud. But I guess it could be hysteria. Or not.