SINGAPORE - Previously revised in 2000, the newest edition of the psychiatrist's bible called the Diagnostic And Statistical Manual Of Mental Disorders (DSM-5) is set to be released next month. In it is a bizarre new diagnosis called body integrity identity disorder (BIID).
Initially thought to be a psychological condition called apotemnophilia, or the desire to be an amputee, it is now thought to be an organic brain disorder producing a disruption of the body image.
You did read it correctly: the desire to be an amputee. A person suffering from this feels that a particular limb doesn't belong to him, so it should not be there and ought to be cut off. Never a trite fantasy, the obsession causes so much distress, his social and work life are greatly disrupted. Importantly, these patients don't have any other psychiatric condition.
Calling themselves "wannabes", BIID sufferers have set up websites to share relatively painless ways of amputating a limb. Those who can't find a surgeon to do the job have been known to use weights to crush the offending limb, or pack it in dry ice to freeze it dead, say, so that surgeons are compelled to amputate it.
Some such attempts have led to deaths, so surgical amputations could prevent some deaths.
A 2012 study concluded amputation "appears to result in remission of BIID and an impressive improvement of quality of life".
Recent functional magnetic resonance imaging studies suggest that, in BIID, the brain region that houses one's body schema is not well activated when the offending limb is rubbed. It may be because the region doesn't work well, so there is a mismatch between the wannabe's body and body image. Indeed, when that brain region suffers a stroke or has a tumour, symptoms akin to BIID emerge.
In contrast, BIID starts early in life, unlike tumours or strokes that occur more often in adulthood, which suggests that BIID may arise from a congenital disorder in that brain region.
In his book A Leg To Stand On (1984), New York University neurologist Oliver Sacks described a young man with a tumour in that brain region that bled out one night. He woke up to find what he thought was someone else's leg in his bed. He tried throwing it out of his bed, only to find himself flat out on the floor because the leg was somehow attached to him.
The man felt that his own leg had somehow disappeared. After the tumour was resected, his leg "came back", so Dr Sacks postulated the bleeding had "erased the leg centre" in his body schema.
In 1974, a fall in a remote region in Norway left Dr Sacks himself seriously injured in his left thigh. After it healed, he experienced a strange condition where he felt no connection to the thigh: "In that instant, that very first encounter, I knew not my leg. It was utterly strange... alien and incomprehensible... It was absolutely not me and yet, impossibly, it was attached to (and) continuous with me... Amputation would relieve me of having to drag around a totally useless, functionless limb."
Eventually, Dr Sacks did recover full ownership and use of his leg. Perhaps bodily injuries may sometimes disrupt communication between a limb and the brain body schema region. Some wannabes do report injuries to the offending limb in childhood.
Self-amputation in schizophrenia is not unknown, but this is not BIID since it is driven by delusions such as "This is my mission that God gave me" or "I must get rid of the Devil who has entered my hand to make me do bad things". In BIID, though bizarre, the patient is not delusional at all.
Should a surgeon amputate the offending limb for a BIID wannabe who has had the desire for many years, is clearly not psychotic or delusional, and keenly aware of the procedure's permanent consequences? The strongest argument is that it would prevent him from hurting or even killing himself: Amputation is the lesser evil.
But amputating a healthy limb inflicts a disability, whereas doctors are to do no harm. The wannabe could say this defines harm too narrowly, while the offending limb causes him anguish that, to him, is the far greater harm.
But consider anorexia nervosa, in which there is also a mismatch between body type and body image. The patient believes she is too fat when her weight is, in fact, so low as to threaten life. No surgeon would perform stomach stapling for her, though it would relieve her of her anguish too.
Second, removing healthy tissues seems unethical. However, this is done in gender reassignment surgery, which causes an irreversible change that also ends the patient's anguish. Or the removal of healthy breasts and ovaries in women at high genetic risk of breast cancer. Or women who want their breasts reduced though this will render them permanently unable to breastfeed. Yet all these procedures are considered ethical.
Third, amputation's rate of cure for BIID is not established. But then, patients do receive experimental therapies as long as they give their informed consent. Respect for his autonomy means that his informed consent renders his elective amputation ethical.
Yet no amount of reasoning can overcome the gut feeling that "this must be wrong". With DSM-5 legitimising BIID as a disorder, might more people begin to use it to construct their identities that, in a feedback loop, then reinforces that mental construction as a medical diagnosis?
In Rewriting The Soul (1995), Canadian philosopher Ian Hacking described how psychiatric diagnoses have this "looping" effect that, he argued, has already happened with the dissociative identity disorder diagnosis.
Hopefully, not with BIID.
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