In 1973, Sweden was gripped by a sensational heist that saw four bank workers taken hostage by a criminal named Jan-Erik Olsson and an accomplice. Over the course of the six-day standoff between Olsson and the police, one of the captives—Kristin Enmark—developed a rapport with the jailers and displayed fear of the Swedish authorities attempting to free her. Following Enmark’s release, this reaction was pathologized by the psychiatrist who led the police’s efforts, and the term “Stockholm syndrome” was born.

In the years since, Stockholm syndrome has been expanded to describe any psychological condition in which a victim of abuse forms an emotional attachment to their abuser. It has been immortalized in film, from the abducted heroine who falls in love with her captor in Buff...