

Folie a deux is an idiomatic French expression meaning "craziness of two." This fascinating syndrome is referred to diagnostically in the American Association's -IV-TR as Shared Psychotic Disorder, one of several types of . How common is this condition, what causes it, and what can it teach us about the nature and perils of ?

A delusion is, by definition, a psychotic symptom: a fixed, false, irrational conviction not comporting with objective reality but clung to vehemently nonetheless. Shared Psychotic Disorder refers to the onset of such a state of mind in someone as a consequence of close relationship with another person already suffering from psychosis. Yes, in this sense, psychosis can be communicable. This relatively rare mental disorder illustrates two vital truths: Psychosis--contrary to the conventional mainstream view--is most often not merely the manifestation of biochemical aberration or a "broken brain," but a fundamentally psychological phenomenon. And, as such, it demonstrates the dangerous degree to which the human mind is capable of massive self-deception. It proves the awesome power of psychology.

None of us are beyond deceiving ourselves. Such self-deception, which in its most extreme and pathological forms we deem delusional, is much more pervasive than most imagine. Consider the ordinary example of some heated conflict with a spouse, lover, relative or close friend. How is it that after the fact, each participant can have a completely contradictory version of what happened? Objectively speaking, first A happened, then B occurred, then C was said, D followed, etc. But what if the objective facts or our own behavior don't comport well with how we see ourselves? We distort the facts to support our particular point of view and to sustain our beliefs about the kind of person we are or want to be. When the objective facts threaten the ego and its integrity, we experience what social psychologists call "confirmation bias," a kind of cognitive dissonance known more recently as "Morton's Demon." We dismiss certain facts incompatible with our myth of ourselves in favor of other less threatening and more corroborative ones. We twist the truth. And we become convinced of the veracity of this twisted truth. And we do all this unconsciously. We don't even know we're doing it. This goes beyond mere "cognitive distortion," resulting in a radical rewriting of history and reality for the purpose of preserving our precious or persona. In its most extreme form, such self-deception can lead to certain delusional beliefs symptomatic of psychosis. This illustrates clearly the powerful cognitive component of psychotic disorders of various kinds.

Take the current Casey Anthony case (see my previous post). Casey Anthony is charged with the first-degree murder of her missing two-year-old daughter, Caylee. From the start, Casey has denied any culpability, claiming steadfastly that her daughter was abducted by her babysitter. Is this the objective truth? Or is it a lie? If it is a lie, is it a conscious lie or an unconscious one? In other words, does Casey know she's lying? Or does she actually believe the lie? If she turns out to be completely convinced that the lie is true, is she really lying? Or is she telling the truth as she sees it? If the latter turns out to be the case, then Casey could be considered delusional. From a perspective, this could conceivably become a key component of her legal defense.

But what of Casey's parents, especially her mother, Cindy Anthony? Both seem convinced that Casey did not harm their granddaughter and is telling authorities the truth. Is this a conscious show of support and solidarity for their daughter, an effort to protect her from abandonment and prosecution? Are they lying? Do they speak of Casey's innocence outwardly but inwardly believe in her ? Or are they lying to themselves? Denial is a potent form of self-deception, an unconscious psychological designed to ward off unacceptable or inconvenient truths. Could Casey Anthony's parents be, perhaps like her, so deeply in denial that they have introjected their daughter's delusional belief about what happened, becoming enmeshed in a folie a trois?

While such cases are extreme, this sort of symbiotic dynamic is present in most relationships to some extent, with partners regularly entering into and supporting the subjective reality of the other. Even when that necessitates deceiving themselves to do it. Evidence of this can be commonly seen in relationships in which the severity of abusive behavior or or mental illness in one person is minimized by the other. This insidious self-deception occurs not only in couples, but in families, friendships, groups, religious cults, political parties and entire countries. Cognitive dissonance leads us to disregard or negate all that could contradict our cherished self-image or insult our personal or collective . So the truth we see is highly selective, serving to reinforce primarily our experience of ourselves as good, kind, honest, religious, , loving, etc. Or, in some cases, or Morton's Demon can even lead to the rejection of positive qualities which seem incompatible with one's deeply entrenched negative view of oneself, thus destructively perpetuating it.

Interestingly, when the individuals in a folie a deux are eventually separated, the person who adopted the other's delusional beliefs typically no longer exhibits psychotic symptoms, while the original and more dominant delusional partner (the "inducer" or "primary case") remains psychotic. Why is that? It is due partially to the fact that the person who takes on another's delusional system is somewhat more psychologically intact compared to the inducer to begin with. Therefore, when removed from the delusional inducer's direct influence, they no longer fully partake in nor endorse his or her distorted subjective reality. Indeed, they may have passively or even lovingly joined with the other for the sake of solidarity and support in his or her delusional version of reality precisely so as not to abandon or be abandoned by the other. A concrete illustration of this dynamic can be seen in cults of various kinds, in which passive followers fanatically internalize the 's grandiose and paranoid delusions. Think Charles Manson, Jim Jones, David Koresh, Adolf Hitler, Osama bin Laden and others. If and when susceptible followers leave the cult, these symptoms tend to diminish over time.

In truth, we deceive ourselves about a great many matters, from bad behavior, to how we feel, to the ever present existential fact of death. Such self-deception is fundamentally related to 's broad conception of the unconscious--the unknown aspects of our psyche--and specifically to Jung's notion of the shadow: those unacceptable traits and tendencies in ourselves we hide from both others and ourselves. This very capacity to deny our own selfishness, fears, cruelty and complicity in evil-- unconsciousness-- is itself a treacherous sort of self-deception. Which is why growing gradually more conscious during the course of can be a shocking, painful and sobering process. C. . Jung noted the therapeutic importance of consciously tolerating the "tension of opposites" we today term " ," and that such unadulterated confrontation with the truth about oneself is almost always initially experienced as an insult to the ego--a devastating blow to our narcissism. No wonder we so fervently resist this process. It takes considerable courage and commitment to be brutally honest with oneself. But it is precisely this willingness to stop our chronic self-deception and face the truth that finally sets us free.