Shared Psychotic Disorder. Also known as "Folie à Deux", this seldom diagnosed, but all-too-commonly observed type of psychosis occurs when an otherwise healthy person develops delusions after associating with one or more independently psychotic delusional people. In other words, this diagnosis applies to people who have been isolated and "brainwashed" by people or groups with delusional and dogmatic agendas. The cure for this condition is social; patients need to be separated from their delusional associate(s), and shown the inconsistency and irrationality of their delusional beliefs. This task becomes more complicated when patients' delusions involve religious themes because religious convictions cannot be argued in rational, logical terms; they are instead articles of faith.
The following diagnostic criteria must be met before a diagnosis of Shared Psychotic Disorder is warranted, according to the DSM-IV-TR:
A) A delusion develops in an individual in the context of a close relationship with another person(s), who has an already-established delusion.
B) The delusion is similar in content to that of the person who already has the established delusion.
C) The disturbance is not better accounted for by another Psychotic Disorder (e.g., Schizophrenia), or a Mood Disorder With Psychotic Features and is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.