Folie à Deux is a psychiatric disorder, first described by French psychiatrists Falret and Baillarger in 1877, in which two individuals, usually related, share a single delusional system. This disorder is also referred to as shared psychotic disorder, induced psychosis, and psychogenic folie commune.
The disorder is characterized by one of the individuals having an existing mental illness with delusions, and the second individual developing similar delusions as a result of the first individual’s influence. This could be due to a close relationship between the two individuals, such as family members, or partners in an intimate relationship. In the case of family members, the individual with the existing mental illness is usually the dominant one and is typically the one instigating the delusions to the second individual. Folie à Deux is not as common as other psychiatric disorders, but it is important to be aware of as it can be misdiagnosed as schizophrenia or other psychotic disorders.
The symptoms of Folie à Deux are similar to those seen in other mental illnesses, such as delusions, hallucinations, disorganized speech, and inappropriate behavior. The delusions and hallucinations shared by the individuals are usually similar, and may involve themes of persecution, grandiosity, or love. The symptoms may last for varying lengths of time, and can range from a few weeks to several years.
Treatment for Folie à Deux is similar to that for other mental illnesses. It typically involves a combination of psychotherapy and medication, as well as education about the disorder and its effects. It is important to recognize the underlying mental illness of the individual who is instigating the delusions, and to treat that condition.
Folie à Deux is an interesting and complex disorder that is not as widely known as other mental illnesses, but it is important to be aware of it and to recognize its symptoms. For further reading, please see the following scientific journal articles:
-Gillespie, K.T., & Malcolm, M. (2014). Shared Psychotic Disorder in the Elderly. The American Journal of Geriatric Psychiatry, 22(9), 956-963.
-Rudorfer, M.V., & Manji, H.K. (2016). A New Look at Shared Psychotic Disorder: Dyadic Psychosis. Harvard Review of Psychiatry, 24(1), 58-70.
-Saif, N., & Yudofsky, S.C. (2015). Shared Psychotic Disorder: Clinical Considerations. Psychiatric Times, 32(6), 1-5.