Shared Psychotic Disorder, also known as folie à deux, is a rare mental condition in which two or more individuals develop and share a specific delusional belief. This disorder occurs when a person who already has a diagnosable psychotic disorder, such as schizophrenia, influences another individual close to them to adopt the same or similar delusional thinking. The two people involved are usually in a close relationship, such as family members or romantic partners, leading to the term "shared" psychotic disorder.
The shared delusion is usually confined within the boundaries of the primary case, the individual with the pre-existing psychotic disorder. The secondary case, the person without the initial psychotic disorder, does not typically display other symptoms of psychosis when separate from the primary case. However, upon close association with the primary case, they begin to adopt the delusional beliefs and behavior.
This phenomenon is thought to occur due to factors such as genetic vulnerability, a dominating influence exerted by the primary case, or emotional bonding between the individuals. The shared delusion may involve grandiose or persecutory themes and can range in severity. Treatment typically involves therapy and medication targeting the primary case's underlying psychotic disorder, as resolving their delusional beliefs often leads to improvement in the secondary case's symptoms as well.
Shared Psychotic Disorder is a complex and rare psychiatric condition that requires careful evaluation, diagnosis, and treatment to help restore the affected individuals' well-being and overall functioning.