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The science of voodoo: When mind attacks body

13 May 2009 by Helen Pilcher NewScientist
Magazine issue 2708. Subscribe and get 4 free issues.
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There are numerous documented instances from many parts of the globe of people
dying after being cursed (Image: Image Source/Rex)
Editorial: Breaking the voodoo spell

Late one night in a small Alabama cemetery, Vance Vanders had a run-in with the
local witch doctor, who wafted a bottle of unpleasant-smelling liquid in front
of his face, and told him he was about to die and that no one could save him.

Back home, Vanders took to his bed and began to deteriorate. Some weeks later,
emaciated and near death, he was admitted to the local hospital, where doctors
were unable to find a cause for his symptoms or slow his decline. Only then did
his wife tell one of the doctors, Drayton Doherty, of the hex.

Doherty thought long and hard. The next morning, he called Vanders's family to
his bedside. He told them that the previous night he had lured the witch doctor
back to the cemetery, where he had choked him against a tree until he explained
how the curse worked. The medicine man had, he said, rubbed lizard eggs into
Vanders's stomach, which had hatched inside his body. One reptile remained,
which was eating Vanders from the inside out.

Doherty then summoned a nurse who had, by prior arrangement, filled a large
syringe with a powerful emetic. With great ceremony, he inspected the instrument
and injected its contents into Vanders' arm. A few minutes later, Vanders began
to gag and vomit uncontrollably. In the midst of it all, unnoticed by everyone
in the room, Doherty produced his pièce de résistance - a green lizard he had
stashed in his black bag. "Look what has come out of you Vance," he cried. "The
voodoo curse is lifted."

Vanders did a double take, lurched backwards to the head of the bed, then
drifted into a deep sleep. When he woke next day he was alert and ravenous. He
quickly regained his strength and was discharged a week later.

The facts of this case from 80 years ago were corroborated by four medical
professionals. Perhaps the most remarkable thing about it is that Vanders
survived. There are numerous documented instances from many parts of the globe
of people dying after being cursed.

With no medical records and no autopsy results, there's no way to be sure
exactly how these people met their end. The common thread in these cases,
however, is that a respected figure puts a curse on someone, perhaps by chanting
or pointing a bone at them. Soon afterwards, the victim dies, apparently of
natural causes.

Voodoo nouveau

You might think this sort of thing is increasingly rare, and limited to remote
tribes. But according to Clifton Meador, a doctor at Vanderbilt School of
Medicine in Nashville, Tennessee, who has documented cases like Vanders, the
curse has taken on a new form.

Take Sam Shoeman, who was diagnosed with end-stage liver cancer in the 1970s and
given just months to live. Shoeman duly died in the allotted time frame - yet
the autopsy revealed that his doctors had got it wrong. The tumour was tiny and
had not spread. "He didn't die from cancer, but from believing he was dying of
cancer," says Meador. "If everyone treats you as if you are dying, you buy into
it. Everything in your whole being becomes about dying."

He didn't die from cancer but from believing he was dying of cancer
Cases such as Shoeman's may be extreme examples of a far more widespread
phenomenon. Many patients who suffer harmful side effects, for instance, may do
so only because they have been told to expect them. What's more, people who
believe they have a high risk of certain diseases are more likely to get them
than people with the same risk factors who believe they have a low risk. It
seems modern witch doctors wear white coats and carry stethoscopes.

The idea that believing you are ill can make you ill may seem far-fetched, yet
rigorous trials have established beyond doubt that the converse is true - that
the power of suggestion can improve health. This is the well-known placebo
effect. Placebos cannot produce miracles, but they do produce measurable
physical effects.

The placebo effect has an evil twin: the nocebo effect, in which dummy pills and
negative expectations can produce harmful effects. The term "nocebo", which
means "I will harm", was not coined until the 1960s, and the phenomenon has been
far less studied than the placebo effect. It's not easy, after all, to get
ethical approval for studies designed to make people feel worse.

What we do know suggests the impact of nocebo is far-reaching. "Voodoo death, if
it exists, may represent an extreme form of the nocebo phenomenon," says
anthropologist Robert Hahn of the US Centers for Disease Control and Prevention
in Atlanta, Georgia, who has studied the nocebo effect.

In clinical trials, around a quarter of patients in control groups - those given
supposedly inert therapies - experience negative side effects. The severity of
these side effects sometimes matches those associated with real drugs. A
retrospective study of 15 trials involving thousands of patients prescribed
either beta blockers or a control showed that both groups reported comparable
levels of side effects, including fatigue, depressive symptoms and sexual
dysfunction. A similar number had to withdraw from the studies because of them.

Occasionally, the effects can be life-threatening (see "The overdose"). "Beliefs
and expectations are not only conscious, logical phenomena, they also have
physical consequences," says Hahn.

Nocebo effects are also seen in normal medical practice. Around 60 per cent of
patients undergoing chemotherapy start feeling sick before their treatment. "It
can happen days before, or on the journey on the way in," says clinical
psychologist Guy Montgomery from Mount Sinai School of Medicine in New York.
Sometimes the mere thought of treatment or the doctor's voice is enough to make
patients feel unwell. This "anticipatory nausea" may be partly due to
conditioning - when patients subconsciously link some part of their experience
with nausea - and partly due to expectation.

Alarmingly, the nocebo effect can even be catching. Cases where symptoms without
an identifiable cause spread through groups of people have been around for
centuries, a phenomenon known as mass psychogenic illness. One outbreak (see
"It's catching") inspired a recent study by psychologists Irving Kirsch and
Giuliana Mazzoni of the University of Hull in the UK.

They asked some of a group of students to inhale a sample of normal air, which
all participants were told contained "a suspected environmental toxin" linked to
headache, nausea, itchy skin and drowsiness. Half of the participants also
watched a woman inhale the sample and apparently develop these symptoms.
Students who inhaled were more likely to report these symptoms than those who
did not. Symptoms were also more pronounced in women, particularly those who had
seen another apparently become ill - a bias also seen in mass psychogenic
illness.

The study shows that if you hear of or observe a possible side effect, you are
more likely to develop it yourself. That puts doctors in a tricky situation. "On
the one hand people have the right to be informed about what to expect, but this
makes it more likely they will experience these effects," says Mazzoni.

This means doctors need to choose their words carefully so as to minimise
negative expectations, says Montgomery. "It's all about how you say it."

Hypnosis might also help. "Hypnosis changes expectancies, which decreases
anxiety and stress, which improves the outcome," Montgomery says. "I think
hypnosis could be applied to a wide variety of symptoms where expectancy plays a
role."

Is the scale of the nocebo problem serious enough to justify such
countermeasures? We just don't know, because so many questions remain
unanswered. In what circumstances do nocebo effects occur? And how long do the
symptoms last?

It appears that, as with the placebo response, nocebo effects vary widely, and
may depend heavily on context. Placebo effects in clinical settings are often
much more potent than those induced in the laboratory, says Paul Enck, a
psychologist at the University Hospital in Tübingen, Germany, which suggests the
nocebo problem may have profound effects in the real world. For obvious reasons,
though, lab experiments are designed to induce only mild and temporary nocebo
symptoms.

Real consequences

It is also unclear who is susceptible. A person's optimism or pessimism may play
a role, but there are no consistent personality predictors. Both sexes can
succumb to mass psychogenic illness, though women report more symptoms than men.
Enck has shown that in men, expectancy rather than conditioning is more likely
to influence nocebo symptoms. For women, the opposite is true. "Women tend to
operate more on past experiences, whereas men seem more reluctant to take
history into a situation," he says.

What is becoming clear is that these apparently psychological phenomena have
very real consequences in the brain. Using PET scans to peer into the brains of
people given a placebo or nocebo, Jon-Kar Zubieta of the University of Michigan,
Ann Arbor, showed last year that nocebo effects were linked with a decrease in
dopamine and opioid activity. This would explain how nocebos can increase pain.
Placebos, unsurprisingly, produced the opposite response.

Meanwhile, Fabrizio Benedetti of the University of Turin Medical School in Italy
has found that nocebo-induced pain can be suppressed by a drug called
proglumide, which blocks receptors for a hormone called cholecystokinin (CCK).
Normally, expectations of pain induce anxiety, which activates CCK receptors,
enhancing pain.

The ultimate cause of the nocebo effect, however, is not neurochemistry but
belief. According to Hahn, surgeons are often wary of operating on people who
think they will die - because such patients often do. And the mere belief that
one is susceptible to a heart attack is itself a risk factor. One study found
that women who believed they are particularly prone to heart attack are nearly
four times as likely to die from coronary conditions than other women with the
same risk factors.

Despite the growing evidence that the nocebo effect is all too real, it is hard
in this rational age to accept that people's beliefs can kill them. After all,
most of us would laugh if a strangely attired man leapt about waving a bone and
told us we were going to die. But imagine how you would feel if you were told
the same thing by a smartly dressed doctor with a wallful of medical degrees and
a computerful of your scans and test results. The social and cultural background
is crucial, says Enck.

Meador argues that Shoeman's misdiagnosis and subsequent death shares many of
the crucial elements found in hex death. A powerful doctor pronounces a death
sentence, which is accepted unquestioningly by the "victim" and his family, who
then start to act upon that belief. Shoeman, his family and his doctors all
believed he was dying from cancer. It became a self-fulfilling prophecy.

"Bad news promotes bad physiology. I think you can persuade people that they're
going to die and have it happen," Meador says. "I don't think there's anything
mystical about it. We're uncomfortable with the idea that words or symbolic
actions can cause death because it challenges our biomolecular model of the
world."

Perhaps when the biomedical basis of voodoo death is revealed in detail we will
find it easier to accept that it is real - and that it can affect any one of us.

Editorial: Breaking the voodoo spell

The overdose
Depressed after splitting up with his girlfriend, Derek Adams took all his
pills... then regretted it. Fearing he might die, he asked a neighbour to take
him to hospital, where he collapsed. Shaky, pale and drowsy, his blood pressure
dropped and his breaths came quickly.

Yet lab tests and toxicology screening came back clear. Over the next 4 hours
Adams received 6 litres of saline, but improved little.

Then a doctor arrived from the clinical trial of an antidepressant in which
Adams had been taking part. Adams had enrolled in the study about a month
earlier. Initially he had felt his mood buoyed, but an argument with his
ex-girlfriend saw him swallow the 29 remaining tablets.

The doctor revealed that Adams was in the control group. The pills he had
"overdosed" on were harmless. Hearing this, Adams was surprised and tearfully
relieved. Within 15 minutes he was fully alert, and his blood pressure and heart
rate had returned to normal.

It's catching
In November 1998, a teacher at a Tennessee high school noticed a "gasoline-like"
smell, and began complaining of headache, nausea, shortness of breath and
dizziness. The school was evacuated and over the next week more than 100 staff
and students were admitted to the local emergency room complaining of similar
symptoms.

After extensive tests, no medical explanation for the reported illnesses could
be found. A questionnaire a month later revealed that the people who reported
symptoms were more likely to be female, and to have known or seen a classmate
who was ill. It was the nocebo effect on a grand scale, says psychologist Irving
Kirsch at the University of Hull in the UK. "There was, as far as we can tell,
no environmental toxin, but people began to feel ill."

Kirsch thinks that seeing a classmate develop symptoms shaped expectancies of
illness in other children, triggering mass psychogenic illness. Outbreaks occur
all over the world. In Jordan in 1998, 800 children apparently suffered side
effects after a vaccination and 122 were admitted to hospital, but no problem
was found with the vaccine.

Helen Pilcher is a science writer based in the UK




Seth-Deborah Roth CRNA,CCHt,CI
www.hypnotherapyforhealth.com
read my blog at www.hypnotichealth.blogspot.com
as seen on the "MythBusters"


www.sethdeborahroth.isagenix.com