People tend to rub off on one another when they're emotionally and physically close. Rarely, this influence can go from harmless, like taste in music or how you load the dishwasher, and turn troublesome in the form of psychosis. Infrequent though it may be, shared psychosis, known in medical circles as folie à deux (which means ‘madness of two' in French), is real and potentially devastating to the lives of both people involved.
"Psychosis is hearing, seeing, or believing things that are not real or true," explains Chicago-based forensic psychiatrist Dr. Andrew Segovia Kulik in an email. "Simply using logic, if someone you love and trust gets psychotic, then sometimes the psychosis can be transferred."
Individual psychosis affects about three in 100 people at some point during their lives, and about 100,000 young people in the U.S. each year. Warning signs that precede psychosis can include uneasiness with others, difficulty concentrating, decline in job or school performance, lack of emotions and increased isolation.
If these are ignored, the condition could bloom into active psychosis. Active psychosis is usually accompanied by delusions (strong beliefs that seem irrational to others, like believing external forces are controlling your thoughts) or hallucinations (like hearing voices or seeing things that aren't there).
Shared psychosis is much more unusual than an individual psychosis. One database review of medical literature found only 42 cases described between 1993 and 2005. "Shared psychosis is rare, but when it does occur it usually happens between people with close emotional ties," says Dr. A. J. Marsden, assistant professor of psychology and human services at Beacon College in Leesburg, Florida in an email interview. "The delusional belief from one partner provides content for delusional beliefs by the other person. This other person, without their partner, would otherwise not meet the diagnostic criteria for delusional disorder."
A number of risk factors can affect whether or not shared psychosis comes into play. "Mental illness occurs from a genetic predisposition combined with environmental stress," says licensed psychologist Dr. Wyatt Fisher, noting that stressful trigger events can include loss of job, a major health issue or financial problems. "Therefore, if the spouse of someone with psychosis also has a genetic bent towards mental illness and they are experiencing significant amounts of stress they may begin sharing the same psychosis. In addition, if the spouse with the psychosis tends to have a strong influence on the other spouse it's also more likely to happen."
Shared psychosis relationships are often characterized as unusually close. Often, the pair is isolated from others, whether by geography, language barrier or other cultural issues. One famous case involved the Gibbons twins who were black, grew up in Wales and never spoke to anyone but each other. They were bullied heavily at school. After committing acts of arson, they were sent to an institution for the criminally insane. After one of the twins died, the other was released and was able to live a relatively normal life. Interestingly, twin psychosis occurs more often in Western cultures, whereas Japanese data has shown spousal and mother/child combinations to be more common.
"The treatment approach most recommended is to separate the secondary person from the person who is the source of the delusion," says New York City therapist Kimberly Hershenson. "If symptoms have not dissipated within one to two weeks, antipsychotic medications as well as psychotherapy may be necessary."
Hershenson is currently using reality testing as part of a complex treatment plan for a set of parent/child patients dealing with shared psychosis. "I try to pull her away from the delusion," she says of the primary psychosis patient. "So, when she says that she can read people's thoughts, I'll say can you read my thoughts? She'll say, ‘I can't read your thoughts, you're too smart for me,'" she explains. These baby steps cause the patient to gradually realize that her delusions aren't logical. The same method is also helping the secondary psychosis patient to see the light, as well.
Shared psychosis isn't something that's going to go away on its own. "Any type of psychosis is going to create significant impairment almost immediately," Dr. Fisher says, noting that many people experiencing with psychosis have a hard time holding down jobs or maintaining important relationships. "If your spouse does not have psychosis they might be able to help you to get the treatment you need and help stabilize you. But if they also have it they won't be able to help you and it can unravel very fast."
People with psychosis aren't going to admit that there's a problem, either, which makes outside observers critical to getting help. "Definitely be looking for any type of delusional thinking or paranoia or hallucinations," Dr. Fisher says. "Then, if you see the other start to mirror the thought pattern or behavior it could be shared psychosis."