Joker 2: Folie à Deux is based on a true story: The Silent Twins. Although it will be some time before its release, we must confess we’re eager to see Joaquin Phoenix and Lady Gaga as Arthur and Harleen.
The criminal duo is inspired by real events, and it should be noted that Harley Quinn was a mentally healthy person before Joker came into her life. Her real name is Harleen Frances Quinzel, a doctor who works as a psychiatrist at Arkham Asylum.
When Harley and Arthur cross paths, she ends up entering a spiral of madness and “love” that leads her to abandon everything to help her soulmate.
The Silent Twins, the Real Case Behind Joker 2: Folie à Deux
First, you should know that the syndrome of Arthur and Harleen is called, precisely, Folie à Deux, a French expression that translates as “madness of two” or “shared madness”. It refers to a rare psychiatric syndrome that involves paranoia or delirium that is contagious to another person.
“The Silent Twins” is one of the most prominent case studies in psychology of the 70s and 80s.
It is about a pair of sisters, daughters of a Caribbean couple who lived in the UK. Due to racism, the twins suffered tremendous harassment from their surroundings, which gradually caused them to isolate themselves to the point of creating a language that only they understood.

The twins were separated when they were admitted to different boarding schools and were also studied by different medical teams, although when they reunited, their connection was still intact. Therefore, when they reached adolescence, the sisters began to experiment with alcohol and drugs, even starting to steal, rob, and set fires.
A Promise That Could Not Be Broken
The sisters were arrested and the authorities decided to institutionalize them in a high-security mental health hospital in Broadmoor. They spent many years there and made a promise: if one of them died, the other had to start speaking and living like a normal person.
On the day of their release, one of them died of natural causes, and the other sister always claimed that she had sacrificed herself for her, so that she could have a better life and be as close to normal as possible.
The Silent Twins and Joker 2
This case is very similar to the story of the second part of Batman’s villain, as Joker and Harley Quinn develop such a deep connection that only they are capable of understanding, and just like the Silent Twins, the couple is rejected by society.
Arthur is a man with several mental disorders, while Harley is a very asocial woman who has no friends, in fact, her ostracism is her complete downfall.

Another Similar Case
According to the comic book story, Arthur is the one who introduces his disorder to Harley, just like in a case studied in 2018 about a marriage where the woman was mentally healthy, but the husband was not. In the end, she ended up getting involved in his delusions, just like what happens with the characters in the film.
When Is Joker 2: Folie à Deux Released?
Joker 2: Folie à Deux will be starring Joaquin Phoenix and Lady Gaga and will be directed by Todd Philips. Currently, the film is in full production, and its release is scheduled for March 4, 2024.
Story originally written in Spanish by Kate Nateras in Cultura Colectiva.
