Shared Psychotic Disorder Symptoms: Causes, Symptoms, and Treatment Options

Shared Psychotic Disorder, also known as Folie à Deux, is a rare mental health condition where a person shares a delusional belief with another individual. In simpler terms, it is a condition where one person’s belief is transmitted to another individual. The term folie à deux means “madness of two” and was coined by the French psychiatrist Lasègue and Falret in 1877. Although it is a rare condition, it is essential to understand the causes, symptoms, and treatment options associated with shared psychotic disorder.

Causes of Shared Psychotic Disorder

The exact cause of shared psychotic disorder is unknown. However, researchers believe that the condition is caused by a combination of factors, including:

  • Genetic predisposition
  • Environmental factors
  • Stressful life events
  • Neurobiological abnormalities
  • Psychological factors

Research shows that people who are at risk of developing shared psychotic disorder often have a close relationship or have prolonged contact with someone who is delusional. It is also common in couples or family members who are highly dependent on each other.

Symptoms of Shared Psychotic Disorder

Shared psychotic disorder is characterized by having the same delusions as another person. Typically, the person with the primary delusional belief is known as the ‘primary case,’ while the other individual is referred to as the ‘secondary case.’ The secondary case may not have had any delusional beliefs before but develop them through close contact with the primary case.

The delusional beliefs can cover a wide range of topics, including:

  • Persecutory delusions – belief that someone is out to harm them
  • Grandiose delusions – belief that they have superhuman abilities
  • Jealous delusions – belief that their partner is unfaithful to them
  • Somatic delusions – belief that they have a serious medical condition when they do not

A hallmark symptom of shared psychotic disorder is that the delusions are confined to a close relationship, such as a partner, sibling, or parent. The secondary case does not have any delusions outside this relationship.

Treatment Options for Shared Psychotic Disorder

Shared psychotic disorder is a challenging condition to diagnose and treat because the primary case is often not willing to seek help or acknowledge that they have a problem. However, treatment is possible and involves a combination of medication and therapy.

Antipsychotic medication is often prescribed to treat the primary case’s delusional beliefs. This medication works by blocking dopamine receptors in the brain, which can reduce the intensity of the delusions. In some cases, the secondary case may also benefit from taking medication to alleviate their symptoms.

Therapy is also an essential component of treatment for shared psychotic disorder. Cognitive-behavioral therapy (CBT) can be effective in helping the secondary case to recognize and challenge the delusional beliefs. Family therapy can also be beneficial in helping the family to manage the condition and improve communication and relationships.


Shared psychotic disorder is a rare mental health condition that can have a significant impact on individuals and their families. It is essential to understand the causes, symptoms, and treatment options associated with the condition. Although it can be challenging to diagnose and treat, with the right medication and therapy, the condition can be managed successfully. If you or someone you know are experiencing symptoms of shared psychotic disorder, it is essential to seek professional help as soon as possible.


What are the symptoms of Shared Psychotic Disorder?

The symptoms of Shared Psychotic Disorder (also known as Folie à Deux) are characterized by a shared delusion between two people. The delusion is often initiated by one person (the primary case) and then spreads to another person (the secondary case) who is close to them. The secondary case will then adopt the same delusional belief as the primary case. Symptoms can include anxiety, depression, and other psychotic symptoms such as hallucinations and paranoia.

Who is at risk of developing Shared Psychotic Disorder?

Shared Psychotic Disorder is not a common condition but it is more likely to occur among individuals who are in close relationships, such as family members or partners. The disorder is usually triggered by a primary case who has a pre-existing psychotic disorder or has been exposed to a traumatic event. Individuals who have a history of mental illness, substance abuse, or social isolation are also at higher risk of developing Shared Psychotic Disorder.

How is Shared Psychotic Disorder treated?

The treatment for Shared Psychotic Disorder typically involves separating the primary and secondary cases from each other. Therapy can also be used to help the individuals identify and separate from shared delusions. Medications such as antipsychotics may be prescribed to help alleviate symptoms. In some cases, hospitalization may be necessary to provide a safe and supportive environment for the affected individuals.


1. American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.).

2. David, A. S. (1999). Shared psychotic disorder: A critical review of the literature. Canadian Journal of Psychiatry, 44(2), 149–155.

3. Ebadi, S., Rajabizadeh, G., & Neghahban, T. (2015). Shared psychotic disorder: A review of the literature. Iranian Journal of Psychiatry and Behavioral Sciences, 9(2), e2077.