Shared psychosis: When disinformation creates group delusions

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  Quantumrun Foresight
• October 14, 2022

Insight summary

The merging of politics and technology is fueling a crisis of shared psychosis, where hoaxes and conspiracy theories rapidly convince many, often without solid evidence. This phenomenon, known as shared psychosis, is not new but has found a potent breeding ground in social media, enabling the rapid spread of group delusions without the need for direct personal contact. Such widespread delusions, often fueled by false claims and social conformity, have led to significant political events and increased societal division, challenging the very fabric of truth and trust in our societies.

Shared psychosis context

Politics and technology have led to a unique shared psychosis crisis, where people are easily convinced by hoaxes, conspiracy theories, and gossip. Many people are persuaded without solid evidence; consequently, memes, fake news, and propaganda bots have enabled some politicians to build a society of lies, anxieties, fears, and mistrust. A shared psychotic disorder occurs when otherwise mentally healthy individuals repeatedly engage with a delusional person, and the delusion spreads to them as if it were a contagion.

According to psychologist and West Virginia University professor Dale Hartley, the most common type of shared psychosis is folie a deux (French for “madness for two”). French psychiatrists Jean-Pierre Falret and Charles Lasègue were the first to coin the term for this disorder in the 19th century. This shared delusion involves two people, usually a husband and wife, who live together. When shared psychosis spreads to more than two people, it becomes folie a plusiers (madness by many).  

Shared psychosis spread by social media is a dangerous variation of folie a plusiers. Group delusions are usually formed through close and repeated personal contact. However, considering the capacity of social media platforms to trigger outrage, division, and fear, close personal contact is no longer necessary to encourage delusional psychoses. 

There are two reasons why victims may believe false claims: 

1. because negative and conspiratorial statements align with what they want to hear (i.e., confirmation bias), or 


2. because they see many of their peers accepting these hoaxes without question (i.e., conformity). 

Disruptive impact

In particular, two incidents have become the go-to example of how shared psychosis can lead to political turmoil. The first is the rise of QAnon, a cult-like fan base of followers who believe that Donald Trump was secretly fighting a worldwide group of Satanic pedophiles and Democrats in 2017. For gullible fans, the conspiracy theories of anonymous “Q,” who claims to be a high-level government insider, are accepted as “gospel truth.”

According to QAnon, the Satanic group comprised President Joe Biden, Hilary Clinton, former President Barack Obama, and several celebrities. QAnon’s fanbase spread like a virus through social and right-wing news media. Although the QAnon is situated in the US, some experts note that it has been encouraged by foreign disinformation campaigns, mainly political memes and protests staged outside the country.

Another high-profile example of shared psychosis was January 6, 2020, US Capitol riot incited by Donald Trump. During the riot, over 2,000 Trump supporters stormed Capitol Hill, infiltrated, vandalized, and threatened several members of the Democrat Party. Some psychologists attributed this incident to Trump abusing his power to influence a paranoid fanbase. According to psychologists, if an individual displaying symptoms of a mental illness or disorder is placed in a position of authority, their condition can spread to others through emotional connections. This exposure can intensify existing mental health issues and cause delusions, paranoia, and violence in previously healthy people. The only way to treat this exposure is by removing the person from their influential position. 

Implications of shared psychosis

Wider implications of shared psychosis may include: 

• The use of deepfake videos and generated voices fuel more fantastical conspiracy theories.


• More politicians using social media to stage disinformation campaigns to promote their ideologies and conspiracies. These campaigns can lead to more real-world violence against minorities and members of an opposing political party.


• Increased divisiveness on public policies.


• Increased resistance to various established public norms and truths within a given society.


• Increased formation of closed groups in encrypted messaging apps similar to WhatsApp sharing disinformation content.


• Increased pressure on social media platforms to monitor group pages and chat groups for any erratic and violent messaging.

Questions to consider

• How else can shared psychosis affect a country’s politics and policies?


• What can the government do to prevent future violence caused by shared psychosis?