There’s no mystery as to why the notion of multiple personalities has such cultural resonance. For one thing, it’s a notion that rings true in the sense that we all, at times, feel torn between conflicting thoughts or motivations. For another, accounts of people said to be afflicted — patients allegedly cycling between dozens of independent personalities existing inside their own minds — are rather jaw-dropping to read about.

Much of the public’s conception of what used to be known as multiple personality disorder stems from both Flora Rheta Schreiber’s 1973 nonfiction book Sybil, which tells the tale of a psychiatrist, Cornelia B. Wilbur, and her attempts to treat “Sybil” (eventually revealed to be Shirley Ardell Mason), a patient with MPD, as well as the blockbuster made-for-TV movie that sprang from it.

As a new Retro Report shows, Sybil caused a little-known condition to quickly explode into a national hysteria. Soon, thousands of patients were being diagnosed with MPD, and the national fixation with the disorder bled into other cultural panics, such as “recovered” memories detailing sexual abuse, sometimes related to alleged Satanic cults. And it wasn’t just daytime talk-shows spreading these fears and ideas: The psychological and psychiatric Establishments, too, soon began peddling a lot of science that, in retrospect, wasn’t entirely sound.

It’s a fascinating short film and worth watching: