Shared psychotic disorder — also known as “folie à deux” — is a rare disorder involving two or more people who share a delusion or false belief.
Psychosis can be present in various mental health disorders, such as schizophrenia and schizoaffective disorder, and is often characterized as a loss of contact with reality, frequently featuring hallucinations and delusions. It can also occur with certain medical conditions.
If you’re experiencing psychosis, awareness of these symptoms may be challenging. Hallucinations and delusions can feel very real, and you may not know anything is wrong.
It’s common for loved ones to become aware of your symptoms before you do. You might also feel threatened or become irritable when someone tries to challenge your beliefs or experiences during episodes of psychosis.
In rare cases, intimate relationships or close family dynamics can influence delusions and sometimes share them. This is called shared psychotic disorder.
While uncommon, treatment options are available and can be helpful.
Shared psychotic disorder — sometimes called shared delusional disorder — is when two or more people share a delusion or false belief.
The most typical presentation of this condition is when a person prone to psychosis (the “primary” person) influences a person or people who aren’t inclined to psychosis (the “secondary” person) to believe something that isn’t true.
In the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), this disorder is classified under other specified schizophrenia spectrum and other psychotic disorders.
Shared psychotic disorder usually occurs among two people in a close relationship. But sometimes, more than two people in intimate relationships, such as close-knit families, may develop shared psychotic disorder.
This condition is rare, and the first terminology mentioning this disorder dates back to the 1800s.
Folie à deux
Shared psychotic disorder is sometimes called folie à deux, which means “madness shared by two.”
- Folie imposée. In this subtype, two individuals in a close or intimate relationship share a delusion. The person with psychosis often transfers the delusion onto the person without psychosis. However, if the person without psychosis separates from the person with psychosis, the delusion often goes away. Lasgue and Falret identified this subtype in 1877.
- Folie simultanée. Identified in 1880 by Regis, folie simultanée features two people who share psychosis symptoms simultaneously. Genetic and social predispositions may cause you to develop this type of shared psychotic disorder.
- Folie communiquée. Marandon de Montyel identified this subtype in 1881. Here, the second person without psychosis often develops a shared delusion after a period of resistance. But the second person may still have delusions after being separated from the person with psychosis.
- Folie induite. This subtype was identified in 1885 by Lehmann and involved two people with psychosis experiencing new delusions induced by a third person who also has psychosis.
Understanding these subtypes may help determine the right course of treatment for you or your loved one.
Folie a deux can exist in more than two people but is most often seen with two people.
Typical symptoms of shared psychotic disorder include:
- paranoia
- feeling suspicious of others
- being fearful or anxious
- experiencing unrealistic or fixed false beliefs
- becoming angry when your ideas are challenged
- having a “lack of insight” into your mental health
- social withdrawal
- suicidal ideation
- hallucinations
- insomnia
- restlessness
If you’re considering acting on suicidal thoughts, please seek professional support immediately.
Calling or texting a crisis helpline will connect you with a trained counselor 24/7, any day of the year, completely free of charge:
- Call the National Suicide Prevention Lifeline at 988.
- Text HOME to 741741 to reach the Crisis Text Line.
Delusions
Adverse events
The symptoms of shared psychotic disorder can be overwhelming, and treatment may be sought after an adverse event happens due to an episode of psychosis.
For example, you may have false beliefs or delusions that your neighbor is “out to get you” and, in turn, have difficulty focusing on anything besides your neighbor’s actions.
Shared psychotic disorder is a rare condition, and the causes are difficult to pinpoint. More research is still needed on this disorder, as much of the information available comes from case reports.
Some risk factors associated with developing shared psychotic disorder include:
- duration of long-term relationships
- extreme social isolation
- personality disorders
- untreated mental health conditions in the primary individual
- traumatic or stressful life events
- challenges with communication
- cognitive impairment
Shared psychotic disorder most often occurs among married couples but is also prevalent among close siblings.
Treatment for shared psychotic disorder often involves a combination of psychotherapy and medication.
How shared psychotic disorder presents can vary greatly. Different treatment options may be needed for the two or more people affected.
Medication
Many people experience reduced symptoms when prescribed antipsychotic medications.
Mood stabilizers or antidepressants may also help reduce some symptoms of shared psychotic disorders in one or both partners.
Only a doctor can prescribe medication. If you believe that you or a loved one have a shared psychotic disorder, it may be helpful to talk with a psychiatrist about what medications may be beneficial. It’s important to follow treatment guidelines if you’re prescribed medication.
Therapy
Additionally, psychotherapy may help educate you or your loved one on shared psychotic disorder. This can also be helpful for both the primary and secondary individuals with this condition.
Should you separate the people involved?
Expert opinion is mixed on whether separating the primary and secondary individuals is helpful for those living with shared psychotic disorder.
Some studies suggest that separation of the primary and secondary individuals affected can be helpful. But other research indicates that separating the primary and secondary individuals can make shared psychotic disorder worse.
Experiencing psychosis can be terrifying and overwhelming for you and your loved ones. It may not be easy to distinguish what’s real and what isn’t, and you might feel confused or angry about why other people react in certain ways.
Shared psychotic disorder can make it challenging to communicate with others, and it may be hard to reason with people living with this disorder.
If you think you or your loved one may be experiencing shared psychotic disorder, help is available. Treatment options, such as medication and psychotherapy, can help treat this rare condition.
If you are experiencing suicidal thoughts, help is available now through the National Suicide Prevention Lifeline.
Additionally, you can check out this resource locator for mental health treatment and crisis resources.
The National Alliance on Mental Illness (NAMI) also offers education, support, and resources if you’re experiencing psychosis.
Working with a doctor or mental health professional to find a treatment plan that works for you can make a difference in your quality of life. Check out Psych Central’s guide to finding a therapist to get started.