Literally meaning "psychosis of two", folie a deux was first identified by Charles Lasegue and Jean-Pierre Falret in a paper published in Annales Medico-psychologiques in 1877. Although previous clinicians had described "psychic infection" involving mental illness being shared between two or more patients, Lasegue and Falret's now-classic paper described a series of case studies involving women living in close association who manifested identical symptoms (including delusions and hallucinations). They then argued that:
In "folie a deux", one individual is the active element; being more intelligent that the other, he creates the delusion and gradually imposes it upon the second or passive one; little by little the latter resists the pressure of his associate, continuously reacting to correct, modify and coordinate the delusional material. The delusion soon becomes their common cause to be repeated to all in almost identical fashion.
Later clinicians expanded on Lasegue and Falret's original definition and argued three necessary preconditions for folie a deux to occur:
- Definite evidence that the partners were intimately associated,
- The content and motif of the delusional idea must be identical in both partners, and
- Unequivocal evidence that the partners accept, share, and support each other's delusions.
Also known as a "shared paranoid disorder", cases involving shared delusions between three, four, and as many as twelve related individuals have been reported in the clinical literature (folie a quatre, folie a sept, folie a douze, etc.). In all reported cases, the typical pattern involves a dominant partner in the relationship "transmitting" the delusion to the submissive partner. Although the dominant partner is usually psychotic, the actual diagnosis tends to vary, The psychiatric status of the submissive partner is more problematic, however. While Lasegue and Falret argued that the submissive partner in a folie a deux relationship was "not really insane but suffering from temporary moral pressure", later clinicians argued that submissives could also be considered psychotic given their willing adoption of the dominant partner's delusional system which, in turn, shaped their behaviour.
In the case of Christine and Lea Papin, a definite diagnosis can't really be made. Although Christine Papin's paranoia concerning Madame Lancellin and her daughter seemed clear enough, there seemed little evidence that Lea shared her sister's delusion. Although they were both charged with murder, it became apparent to the Le Mans court that Lea was little more than a passive participant who simply obeyed her older sister. Medical experts also determined that Lea had intellectual deficits which made her completely dependent on the more intelligent Christine. Once the final statements were given by both prosecution and defense, the jury only deliberated for a few minutes before finding both sisters guilty. Lea Papin was sentenced to ten years hard labour while Christine Papin was sentenced to death by guillotine. Although Christine refused to appeal the sentence, this was later commuted to life imprisonment and both sisters were sent to a prison in Rennes (they were housed separately).
Christine Papin did poorly in prison and her mental state steadily deteriorated. She became increasingly despondent and wasted away from a refusal to eat. Even when she was brought face to face with Lea, she would claim not to know her (and reportedly stated that "She is very nice, but she is not my sister"). By early 1937, her condition had worsened further and she was transferred to the public asylum at Rennes where she eventually died on May 18. While the official cause of death was lung disease, this was likely linked to her self-induced malnutrition. All clinical records relating to Christine Papin's final years were destroyed in the 1944 bombing of the city. As for Lea Papin, her model behaviour as an inmate earned her a partial remission of her sentence and she was released in 1943. Banned from ever returning to Le Mans, she moved to the city of Nantes where she lived with her mother. Changing her name to "Marie", Lea lived as anonymously as she could given that troublesome reporters continued to seek her out and the notoriety surrounding the case never completely died down. She supported herself as a chambermaid and cleaning woman and she was widely believed to have died in 1982.
Despite being overshadowed by World War II and the Nazi Occupation, public interest in the case remained relatively strong over the years with a series of books, films, and plays inspired by the Papin case. The most famous version of the Papin sisters' story was Jean Genet's classic play The Maids which was first released in 1947. It was later made into a film and an opera. Although interest eventually subsided, the year 2000 saw a remarkable renaissance of interest in the Papin case. Two films were released in that same year, one a dramatization of the Lancellin murders and the second being a documentary on the trial and its aftermath. At about the same time, several new books on the case were also released.
It was the documentary directed by Claude Ventura which stirred up the most controversy however. In the film, Ventura describes his search for Lea Papin including interviews with many of her Nantes neigbours. Although these neighbours appeared unaware of her true identity (despite the fact that she never changed her name), they described her as "delightful little old lady" who enjoyed looking after children and watching her favourite television shows. In a final scene, the documentary concluded at the hospice where Lea Papin had recently been taken following a brain hemorrhage which left her unable to speak or care for herself. The sight of Lea Papin, completely bedridden and apparently unaware that she was being filmed, made for uncomfortable viewing and led to considerable criticism for Claude Ventura and the producers of the documentary (especially since they were unable to prove that the patient shown was actually the Lea Papin involved in the 1933 case). Whatever her true identity, the death of this "Lea Papin" in 2001 marked an apparent end to the saga.
As for the house where the 1933 murders took place, Rene Lancellin continued to live there with a housekeeper until his death in the 1950s (he was never able to sell it after the deaths). Having changed hands several times since M. Lancellin's death, the house at Rue 6 Bruyere is still standing although visitors with a morbid interest in the case might have some trouble finding it. It is apparently the only house on the street without a number.