In 2011, a group of schoolgirls from a small town in upstate New York began experiencing a mysterious neurological condition. Their symptoms included involuntary vocal and physical tics, similar to those associated with Tourette syndrome. The disorder appeared to be highly contagious, spreading quickly through the female ranks of Le Roy Junior-Senior High School. Soon the epidemic attracted the attention of journalists and the environmental activist Erin Brokovich, who suspected it might have to do with toxic contamination. After weeks of medical and environmental testing, and interest on a national level, the epidemic was deemed a case of mass psychosis. Thirteen years have passed and the girls are now women. In Hysterical, the veteran podcast host Dan Taberski talks to those who were affected by the illness, and offers a more nuanced and historically-informed understanding of what was going on. —Paulina Prosnitz