Shared Psychotic Disorder

Shared psychotic disorder is a psychiatric condition which is rarely diagnosed. It is sometimes called “folie a deux”. It occurs when a healthy individual comes to share the delusional beliefs of a psychotic person with whom s/he has a close relationship. For example, person with a psychotic condition may have the delusion that aliens are plotting to destroy the world; if a close friend starts to believe this as well, it is a case of shared psychotic disorder.

Development of the disorder

Shared psychotic disorder usually develops in a relationship in which the dominant person is the one who was already psychotic. The second person is usually more passive, and thus somewhat vulnerable. Typically, the two people have lived together for a long time and are either married or blood relatives. Also, the disorder is more likely to occur when there is a fair to significant degree of social isolation.

With this disorder, the second person’s delusions are not due to some other type of psychotic disorder, such as schizophrenia. Also, they must not be due to a medical condition (e.g., a brain tumor) or caused by the use of a substance, such as drugs or alcohol.

Typically, if the second person is separated from the person who was already psychotic, his/her delusions will subside.


Treatment for this disorder may initially focus on at least a temporary separation of the individuals. If the delusions do not begin to disappear after a reasonable period of separation, a brief regimen of antipsychotic medication is often prescribed for the second person. Psychotherapy can address a variety of related issues, including the social isolation and the nature of the relationship and how those contributed to the development of the disorder.


Overall, the prognosis for the second individual is quite good once s/he is separated from the situation which led to the development of the disorder. However, if there is no separation and no treatment, the psychosis may become chronic.

written by Dr. Cheryl Lane, PsyD