What Is a Psychotic Disorder? A shared psychotic disorder is a rare type of mental illness in which a healthy person starts to take on the delusions of someone who has a psychotic disorder such as schizophrenia. For example, let’s say your spouse has a psychotic disorder and, as part of that illness, believes aliens are spying on him or her. If you have a shared psychotic disorder, you’ll start to believe in the spying aliens. But apart from that, your thoughts and behavior are normal. People with psychotic disorders have trouble staying in touch with reality and often can’t handle daily life. The most obvious symptoms are hallucinations (seeing or hearing things that aren’t real) and delusions (believing things that aren’t true, even when they get the facts).

Troubled Ties Shared psychotic disorders usually happen only in long-term relationships in which the person who has the psychotic disorder is dominant and the other person is passive. These pairs tend to have a close emotional connection to each other. But apart from that, they usually don’t have strong social ties. Shared psychotic disorders can also happen in groups of people who are closely involved with a person who has a psychotic disorder (called folie à plusiers, or "the madness of many"). For instance, this could happen in a cult if the leader is psychotic and his or her followers take on their delusions. Experts don’t know why it happens. But they believe that stress and social isolation play a role in its development.