While the term is often avoided for fear of ridiculing something more serious, mass psychogenic illness (MPI) — also known as mass sociogenic illness (MSI) or mass hysteria — is a real occurrence that can cause a variety of physical symptoms to manifest in groups of people despite the lack of any physical cause. Often compared to conversion disorder , in which emotional issues are “converted” into physical problems, MPI tends to occur among people who share anxieties, fears, and a sense of community. In the right group of people, it can spread like a virus. A curious case of the condition related to TikTok videos shows both how imagined conditions can spread and how our modern media landscape presents new problems never even dreamt of in a time before the internet. TikTok tics In 2019, a strange slew of new Tourette’s cases made its way into hospitals all over the world. Oddly, these were suddenly occurring in children well over the age of six, the age of typical onset.…