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Criminal power and folie à deux

By Dr Penny Morgan

Penny is a retired zoologist who specialised in bird behaviour, and took a post-retirement law degree. Now, she is trying to write thrillers with an animal welfare theme. She lives in the hope that these will become best-sellers and turned into films. In this article, Penny delves into the psychology of criminal behaviour and explains the term folie à deux. (Reader discretion: one graphic image is displayed below.)

Coercive or controlling behaviour can take the form of stalking, domestic violence, rape, honour-based violence or forced marriage, but perhaps the strangest example of a pathological relationship is termed folie à deux.

The term folie à deux (literally, ‘madness of two’) was first introduced in 1877 by psychiatrists Charles Lasègue and Jean-Pierre Farlet. They employed the term to describe the occurrence of delusions shared by two or more people who live in close proximity and who are relatively isolated from the outside world and its influences. The 'inducer' (or 'primary') creates the delusions from his or her psychosis and imposes them upon a 'passive' individual (the 'induced' or 'secondary'). The passive individual may not be truly psychotic, but 'absurdly credulous'. In the most common form of folie à deux, the primary is typically dominant, intelligent, and autonomous. The secondary is usually submissive, highly suggestible, offering little resistance to accepting the ideas of the primary subject. Social isolation of the subjects is a key aspect, which limits environmental input and opportunities for reality testing. Provided there is no additional underlying psychopathology, there is a good prognosis for the submissive partner.

Some well-known cases of folie à deux

Image: Credit BBC
Fred and Rose West

Rose and Fred West were two of Britain’s most notorious killers, active between 1967 and 1987. Fred was a sexual deviant who had already raped and killed before he met Rose. Rose was the perfect match: a woman who not only went along with his crimes but participated in them. Female victims were kept captive in the basement of their home, where the couple would rape and torture them. When they tired of them, they would kill them, burying their remains in or near their house. At the time of arrest, the pair had killed at least twelve victims, including two of their own daughters and, allegedly, Fred’s first wife. Fred was charged with twelve murders and Rose was charged with ten. He committed suicide in prison before his trial, while Rose was sentenced to life imprisonment.

Image: Cobis
Bonnie and Clyde

Equally infamous were Ian Brady and Myra Hindley, the Moors Murderers. Active between 1963 and 1965, the pair sexually assaulted and killed five children, all between the ages of ten and seventeen. Brady and Hindley met at work when Myra was eighteen. She quickly became infatuated with him and the pair started dating. Hindley returned to Catholicism whilst in prison, while Brady, who had turned to religious texts, was declared criminally insane. It’s not hard to see here who the primary was, but in the case of Bonnie and Clyde, who went on a crime spree in the central US during the Great Depression leaving thirteen dead, it is thought that Bonnie (the female of the pair) was the primary.

Folie à plusieurs

The madness of many (folie à plusieurs) can be found in groups that exist in relative isolation from others and have a dominant leader who is charismatic, arrogant and delusional. Folie à plusieurs is clearly visible in the fanaticism which can infest politics and religion, such as David Koresh of Waco infamy and ISIS (the 'Islamic State' group). More details of both to follow below.


The peculiar love-affair between Trump and his admirers in QAnon (an American political conspiracy theory and political movement) could be a form of folie à plusieurs. Trump's relationship with his fans resembles Shared Psychotic Disorder. Individuals remain trapped in their delusion, unable to see outside the perimeters of their own reality. In the case of Trump, his addled groupies have been induced into believing, among other things, that his barefaced racism is a revival of patriotism. Today, Trump's delusions have taken root in the collective psyche of his devotees and left them in a kind of stupor they can't seem to awaken from. With eccentric and delusional senior leaders in power, subordinates can either comply, perhaps identifying with and internalising the delusion, or they can try to resist in some way, or leave.


Behaviour based on delusional religious beliefs can also evolve into folie à plusieurs. The beliefs of the primary are transferred to close companions, who share and help to sustain such beliefs. This was the structure of al-Qaeda, with Osama bin Laden as its principal inducer. Initially, his delusions were shared and sustained by one or two close associates, in their self-imposed exile from the outside world - folie à deux or folie à trois - but then expanding to suck in vulnerable individuals. Such shared madness might provide some explanation of al-Qaeda’s bizarre and evil suicide-homicide attacks on the USA in September 2001. The perpetrator believes that death is a precondition for the success of the mission, bestowing immortal honour. These terrorists make concrete preparations for their death: they write wills, undertake purification ceremonies, and leave taped messages asking their families not to mourn them, because they are not dead but rather transformed to another life. Thus, religious cults often end in tragedy - frequently at the instigation of the primary.

Reddit image
An aerial view of the Jonestown massacre/suicide

In 1978, the American cult leader Jim Jones led his hundreds of followers in mass murder/suicide, using cyanide. In remote Jonestown, Guyana, 909 people died, a third of them children. There were allegations of physical abuse, including abuse of children.

Another infamous case is that of the 'Branch Davidian' cultists in Waco, Texas, whose leader David Koresh claimed that he was the messiah. In 1993, following a 51-day siege involving both the ATF (the Bureau of Alcohol, Tobacco and Firearms) and the FBI, many of his followers died. Some committed suicide. As is familiar in such cases, there were accusations of polygamy (some ‘spiritual wives’ were as young as eleven) and child abuse. And weirdly, for a supposedly Christian cult, they were armed to the teeth. His many offspring, he claimed, were ‘different’ to the children of others within the cult.

Pseudo-religious death cults like ISIS seem to display features such as blind faith and delusional martyrdom. Participants find themselves in a feedback loop where they reinforce each other's delusions, but common to all is coercion, control and isolation leading to exploitation. A warped reality is created in their minds.

Section 76 of the UK Serious Crime Act 2015 provides for the offence of controlling or coercive behaviour where the perpetrator and the victim are personally connected, such as partners and family members, but currently UK law does not directly address the problem of cults.

You might like to look out for the next Joker movie which will be called Folie à Deux, to be released in October 2024. Director Todd Phillips has co-written the script and Joaquin Phoenix will play the role of Arthur Fleck, the Joker.

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Apr 02, 2023

I know the case of Mark Gordon and Constance Marten - and their dead child - is still sub judice but it seems this too may be a case of one dominant individual overpowering another psychologically.

We will have to wait and see what - if any - evidence emerges during the course of their trial that will help to resolve the actual circumstances of this tragic coupling and the death of their child.

Like the author - and, no doubt, most Humanistically Speaking readers - I am literally astonished at the degree of sanguineness our government presents to the very real dangers of all cults in this country.

One problem may be that they find some of the "useful…


Eric Hayman
Eric Hayman
Apr 01, 2023

"Coercive or controlling behaviour can take the form of stalking, domestic violence, rape, honour-based violence or forced marriage . . ." Also being told it is one's democratic duty to vote at local and general elections - even though there is not a 'None of the above' choice on the voting papers. And it is still called 'Democracy' - rule by the people. Yes, by the people whose names are on the voting papers. Coercive or controlling behaviour comes in many forms.

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