Folie à deux

Folie à deux, shared psychosis, or shared delusional disorder is a psychiatric syndrome in which symptoms of a delusional belief and sometimes hallucinations are transmitted from one individual to another. The same syndrome shared by more than two people may be called folie à trois, folie à quatre, folie en famille ('family madness'), or even folie à plusieurs ('madness of several'). Folie à deux, shared psychosis, or shared delusional disorder is a psychiatric syndrome in which symptoms of a delusional belief and sometimes hallucinations are transmitted from one individual to another. The same syndrome shared by more than two people may be called folie à trois, folie à quatre, folie en famille ('family madness'), or even folie à plusieurs ('madness of several'). Recent psychiatric classifications refer to the syndrome as shared psychotic disorder (DSM-IV – 297.3) and induced delusional disorder (F24) in the ICD-10, although the research literature largely uses the original name. This disorder is not in the current DSM (DSM-5). The disorder was first conceptualized in 19th-century French psychiatry by Charles Lasègue and Jean-Pierre Falret and is also known as Lasègue-Falret syndrome. The term is from French for 'madness of two'. This syndrome is most commonly diagnosed when the two or more individuals concerned live in proximity and may be socially or physically isolated and have little interaction with other people. Various sub-classifications of folie à deux have been proposed to describe how the delusional belief comes to be held by more than one person: Folie à deux and its more populous cousins are in many ways a psychiatric curiosity. The current Diagnostic and Statistical Manual of Mental Disorders states that a person cannot be diagnosed as being delusional if the belief in question is one 'ordinarily accepted by other members of the person's culture or subculture' (see entry for delusion). It is not clear at what point a belief considered to be delusional escapes from the folie à... diagnostic category and becomes legitimate because of the number of people holding it. When a large number of people may come to believe obviously false and potentially distressing things based purely on hearsay, these beliefs are not considered to be clinical delusions by the psychiatric profession and are labelled instead as mass hysteria. As with most psychological disorders, the extent and type of delusion varies, however it usually mimics the delusion of the inducer and is almost very similar to it. The inducer does not realize that they are making the other person sick but instead think they are helping by alerting the second person of what they deem to be 'truth'. Psychology Today magazine defines delusions as 'fixed beliefs that do not change, even when a person is presented with conflicting evidence'. There are 4 main types of delusions that are passed on from an inducer to a secondary person: Bizarre delusions, Non-bizarre delusions, Mood-congruent delusions and Mood neutral delusions. No-one knows what causes SDD exactly but stress and social isolation are the main contributors. When we are socially isolated the few people we do talk to become very important to us, and therefore they are seen as more trustworthy, so when an inducer is sharing their delusions, the second person is more likely to believe them. Additionally, since they are socially isolated people developing shared delusional disorder do not have others reminding them that their delusions are either impossible or not likely and are therefore more likely to develop SDD. In fact, the treatment for shared delusional disorder is for the person to be removed for the inducer and seek additional treatment if necessary. Stress is also a factor because it triggers mental illness. The majority of people that develop shared delusional disorder are genetically predisposed to mental illness, however this predisposition ( i.e. genes for schizophrenia that need to be activated) is not enough to develop a mental disorder. However, when that person becomes stressed their adrenal gland releases the stress hormone cortisol into the body which released increased levels of dopamine in their brain and changes in dopamine levels are linked to mental illness. As a result, stress puts one at a heightened risk of developing a psychological disorder such as shared delusional disorder. Shared delusional disorder is hard to diagnose because usually, the afflicted person does not seek out treatment because they do not realize that their delusion is abnormal as it comes from someone in a dominant position who they trust. Furthermore, since their delusion comes on gradually and grows in strength over time, their doubt is slowly weakened during this time. Shared delusional disorder is diagnosed using the DSM-5 and according to this the person afflicted must meet three criteria: