When delusion triumphs over truth

New Scientist, 28 January 2006
ALISON MOTLUK

BELIEF has never literally moved a mountain, but it can have some dramatic effects. Take Madeleine Rizan. By the time she bathed in the waters of Lourdes in 1858 she had been paralysed for 24 years, yet, according to the record, she regained her ability to move. Then there are the dozens of heart patients in the 1950s who were helped by a procedure known as internal mammary ligation - which worked just as well when patients simply believed it had been done. There are even instances of women who stop menstruating, grow a round belly and begin to lactate, in the firm but mistaken belief that they are pregnant. Equally mysterious are the paralysed people who believe their limbs are still working normally, despite the evidence of their own eyes.

What is going on inside our brains when we believe? How does that trigger physical changes in our bodies? And why would our minds believe the world is a certain way in flat contradiction to the evidence of our own senses? Or, put another way, what exactly is the biological basis of belief? "It's a fascinating question and poorly studied," says Vilayanur Ramachandran, a neurologist at the University of California at San Diego who has spent much of his career studying "disorders of belief". Dean Hamer, from the US National Institutes of Health in Bethesda, Maryland, and author of The God Gene, goes further. "We have absolutely no idea," he says. "Nobody has any idea."

In brighter moments, even Hamer would admit the picture is not quite as grim as that. There seem to be at least two lines of thinking on the matter. One is that belief in the widest sense is primarily a product of rationality and reasoning. In order to believe in something, you have to know vaguely what it is and how it will play out. The other is that believing is more emotional - a sort of gut reaction. "That's why people feel belief and don't think belief," says Hamer, who is inclined towards the latter camp.

Getting a handle on the biological basis of belief is not easy. It is extremely difficult to study how faith in God's power to heal can actually heal, for instance. Luckily, there is an alternative. Faith in medicine is almost as ubiquitous as faith in God, and the effects are far easier to control and to measure. We know, for instance, that about 80 per cent of the effect of antidepressants derives from people's faith that they will work (Prevention & Treatment, vol 5, p 23). The influence of belief may be even stronger in alternative medicine. A study out last September showed that acupuncture seems to alleviate headaches no matter where in the body you stick the needles or how you twiddle them (British Medical Journal, vol 331, p 376). And countless medical studies have used placebos to show that belief is a major player in the healing process. "The best way to understand the scientific effect of belief is to look at the literature on the placebo effect," says Herbert Benson, director of the Mind/Body Medical Institute in Boston.

Put simply, the placebo effect is the biological impact of believing in a medical treatment. There is no doubt that it is a real and powerful force. The question is, how exactly does it work. Last year, Jon-Kar Zubieta at the University of Michigan at Ann Arbor published research that tackled the issue head-on. He gave 14 healthy men infusions to make their jaws ache. They were then given a treatment that they were told "may or may not relieve pain". In fact, it was only a saline solution, yet all the men reported less pain. And their pain relief was not just subjective. Using positron emission tomography, or PET, to scan their brains, Zubieta found that volunteers produced more endorphins, the body's own natural opioid painkillers, after receiving the placebo (Nature Neuroscience, vol 25, p 7754).

Placebo relief

Combing his data for clues as to what was going on, Zubieta found differences in the way untreated pain and placebo-treated pain affected the brain. With the placebo, not only did people release more endorphins overall, they also released them in additional areas of the brain. These included regions involved in higher-order cognition such as parts of the rostral anterior cingulate, which helps determine how much pain you are feeling, the insular cortex, which receives signals from the body about pain, and the nucleus accumbens, which tells you how important it is. Zubieta also found differences between people who said in advance that they expected to get a lot of relief and those who were more sceptical. In the faithful, he found more endorphins were released in the dorsolateral prefrontal cortex, a cognitive area thought to be involved in decision making, interpretation and selective attention.

All this suggests that the cognitive experience of anticipating relief plays a major role in allowing it to happen. In other words, the evidence supports the hypothesis that belief is a conscious, rational process - a kissing cousin to expectation. And further evidence from behavioural studies seems to bolster this. First and foremost is the fact that to benefit, you have to know you are being treated - the placebo effect won't kick in if a sham medication is given covertly. Similarly, praying for yourself or knowing that family and friends are praying for you seems to produce some positive results, while being secretly prayed for does not (The Lancet, vol 366, p 211).

Experience also appears to be critical. That makes sense, as you have to derive your expectations from somewhere. A study in people with Parkinson's disease, for example, found that after taking a placebo people actually secreted dopamine, the very neurotransmitter they are short on, and at levels similar to that produced by drugs (Science, vol 293, p 1164). But all these patients had previously had positive experiences taking medicines. This is true for many of us. People with a long history of not being helped by conventional medicine, such as those with chronic pain, do not respond well to conventional placebos either. Nor do people with Alzheimer's disease, whose memory impairments or cognitive decline may make it hard to develop the kind of expectations that placebos might depend on. Likewise, children who have no preconception of a particular procedure such as acupuncture get no relief from it.

Perhaps it is not so surprising that expectation and experience are bound up with the placebo effect, which by its very nature is all about the belief that a treatment will or will not work. But underlying this effect is a more stable set of beliefs in the power of medicine in general. There's a direct parallel with other basic beliefs such as religious belief and belief in the evidence of our senses. Myriad such beliefs form the foundations of the way we see the world, and they tend to be very stable. We would be basket cases if every bit of conflicting evidence caused us to alter our world view. Imagine, for example, that you have slept in an awkward position and wake up with no feeling in your arm. You don't immediately assume that you are paralysed.

Yet sometimes we are forced to reassess our deep-held beliefs, and in some cases resistance to change can cause medical oddities. It is these strange conditions that Ramachandran studies to get an insight into the nature of belief.

Imagined experiences

Among the patients he has observed are a group with a condition known as anosognosia, usually caused by stroke. These people deny facts about their bodies, such as that they are paralysed. They will stare at an immobile arm, for example, while insisting they are throwing a ball with it. Ramachandran recalls one case in which he managed to get a woman in denial about the fact that her arm was paralysed to briefly admit it. He did this by providing her with an acceptable way to believe: he told her that he was injecting her arm with an anaesthetic and that it would be temporarily paralysed. After he injected her with a saline solution she did indeed notice that her arm couldn't move. To rule out mere suggestibility, he injected the other arm too, whereupon she complained that the anaesthetic wasn't working.

Ramachandran has studied many such patients. Not all are as resolute as this one. Most anosognosics make excuses, explaining why they don't want to move their paralysed limb - that they have arthritis, for instance, or that the other doctors have already poked and prodded so much that they are fed up. But he has noticed that only patients who have had damage to the right side of their brain confabulate in this way. People with left-side damage, by contrast, are acutely aware of their paralysis and tend to talk about it non-stop.

Such observations have led Ramachandran to suggest that in healthy brains there is a back and forth between believing the old and accepting the new. The left hemisphere, he maintains, tries to impose consistency, whereas the right hemisphere plays devil's advocate, trying to get us to question our beliefs in the light of new evidence. In people with anosognosia, he suspects that brain damage caused by the stroke somehow impairs the right hemisphere's natural scepticism. The left hemisphere is left on its own to uphold the status quo no matter what - even at the risk of becoming delusional.

Much more common examples of such disorders of belief, he suspects, are illnesses such as anorexia and bipolar disorder. People who have anorexia can be completely emaciated yet still look in the mirror and see themselves as fat. In bipolar disorder, the mania phase is often characterised by grandiose and apparently unchecked beliefs. The depressive phase is the opposite, a collapse of self-belief. It is generally accepted that these illnesses disrupt the emotions, so Ramachandran's suggestion that they also have to do with impaired belief systems chimes with the second hypothesis about belief - that it is emotional and akin to longing.

Hamer has raised this idea, arguing that belief - be it in God, medicine or whatever - slightly alters our emotional state. Just as feeling joy has chemical consequences in the brain, so, he speculates, does feeling faith. "Belief," he suggests, "is changing the tenor of the brain." Hamer thinks that belief is mediated by the same neurotransmitters - for example, dopamine and serotonin - that mediate other emotions. He has found, for instance, that there is a variant of a gene called VMAT2 that may be associated with greater spirituality. The VMAT2 protein seems to control the flow in the brain of monoamines, a class of neurotransmitters that includes serotonin and dopamine.

Interestingly, Zubieta's study also indicates a role for emotions. One of his most intriguing findings was that the more people suffered from the pain he induced, the more placebo effect they got. In other words, the greater their longing for relief, the more the endorphins flowed. Zubieta's working hypothesis is that placebos piggyback on the brain's innate painkilling ability, so believing that a treatment will bring relief merely engages this natural system more fully.

Perhaps belief is both a rational process and an emotional one. The picture is still very hazy but, at the very least, attempts to discover the biological underpinnings of belief highlight the fact that it is real: it does have measurable physical effects in our brains. More intriguingly, these effects have the potential to influence the outcome of events. This may even go some way towards explaining the role that self-belief has in helping us achieve our goals in life. If belief in our own abilities can actually bring success, then belief becomes a virtuous circle, a self-fulfilling prophesy. No wonder people are often so often so eager to believe in the first place.