21 October 2005

Delusions And Mental Illness

By Rusty Rockets

We have entered an age where vast numbers of people are moving away from scientific explanations and putting all their energies into believing alternative viewpoints, such as Intelligent Design (ID). The ID movement is so strong that it is slowly being introduced into schools around the globe and given equal weight with the teaching of evolution. The manner that ID is being sold as an alternative to evolution seems to be exploiting a fundamental attribute characteristic of humans: belief creation. But just how do we form our beliefs, and how do we know if a belief that we hold is wrong? One way that researchers are currently exploring this area is by looking at people who suffer from various mental illnesses, such as schizophrenia, where delusions experienced by patients are believed to be true. By taking such an approach, medical researchers can determine whether the belief that a person holds meets the criteria of a delusion. Of additional interest is the fact that some of this research takes in other scientific and philosophical disciplines in an effort to answer some very fundamental questions.

Mental illness is defined as a condition that causes serious abnormality in a person's thinking or behavior. From what is known of the brain, it seems that mental illness is caused either by direct physical damage to the brain itself, or a number of psychological disorders that have developed for one reason or another over time. In the past, these differences have distinguished the fields of study involving the brain and cognition. Traditionally, psychiatry, psychology and other disciplines have played an important role in understanding how the mind functions, while neuroscience has mapped and observed how different areas of the brain interact. In the past, philosophy of mind has not been considered a serious option in regard to the diagnosis and observation of mental illness. But the inclusion of philosophy is becoming more common as psychiatry, psychology and neuroscience advance. The advancement and convergence of the various brain sciences demonstrates how difficult it is to reconcile the physical and psychological processes of the brain, and that the evidence currently available is far from adequate in answering many of the big questions about the brain, such as delusions in the mentally ill.

A rudimentary explanation of delusions is that people strongly believe something to be true in the face of evidence to the contrary, giving rise to false beliefs. These false beliefs can originate in many ways, but more usually they arise because someone may misinterpret another's actions or misread their intentions. But how do we know that these closely held beliefs are actually false? Before discussing that aspect, it might be useful to look at some more obvious examples. Having a "phantom" limb is a condition where a person believes that they can still "feel" a limb long after it has been amputated. The Director of the Center for Brain and Cognition at the University of California, Professor Vilayanur Ramachandran, even refers to cases where it is not uncommon for amputees to believe that their phantom limb waves, picks things up and feels pain. This suggests that limbs are "wired" to other networks within the brain, so that in the case of an amputee the brain continues to register the limb as still present. Ramachandran explains that these sensations are a result of an exact representational "map" of the body, known as the Penfield Homunculus, telling the brain how the body is constructed. The phantom limb comes from the Penfield Homunculus not having had time to readjust after a limb has been removed.

Though the above example does not constitute a mental illness as such, it does raise questions of how much autonomy is present in any person's mind over what we can say we think about. It does seem that much of our thinking relies on "hardwired" neural networks that continue to function long after they have outlived their usefulness. This is probably somewhat true of the way that we hold our own beliefs on cultural phenomenon like religion. This becomes easier to notice when the belief system of a person begins to override or take control of a person's mind, which manifests as a mental illness. Schizophrenic people are just one of many examples where visions and the irrational behavior that they may provoke are something that they find nigh on impossible to control. "Unlike normal people, the schizophrenic can't tell the difference between their own internally-generated images and thoughts versus perceptions that are evoked by real things outside," says Ramachandran. Bill Fulford, Professor of Philosophy and Mental Health in the Department of Philosophy, University of Warwick, says that a: "schizophrenic patient may be well aware that their experience is odd." Unlike the person with the phantom limb, however, it is considerably more difficult, if not impossible, for the schizophrenic to independently verify that they are actually experiencing a delusion, especially if a certain level of paranoia accompanies the delusion.

Neuropsychologist Max Coltheart, from Macquarie University, claims that it's even difficult to say what is meant by delusion. "For instance it seems to me that if you believed 2,000 years ago that the earth was round, that's a delusion. It's a delusion because nobody else believes it and you've got no evidence for it. It happens to be true but you can have delusions that are true, the crucial thing is do you have real evidence for this? Is it what people generally believe? So in our research center we have to be very interdisciplinary, we need someone who can tell us what the concept of belief really means. That's been completely neglected in psychology but it's been studied in philosophy for two and a half thousand years and so a lot of our work is done in collaboration with philosophers of mind who can say, no that's not really what you mean by the concept of belief. So they can say to us 'well, why does a delusion have to be false?' And then one thinks yes, that's a good question, that's a typical philosopher's question. I'm making a mistake if I require that delusions be false. What the philosopher has shown to me is that what I really think is it has to be impervious to evidence. That's what's crucial; it doesn't matter whether it's false or not."

So, if a belief cannot be falsified, if it is impervious to evidence, it is, more than likely, a delusion. Coltheart says that once this criterion for delusions has been established, they can set about finding out why the person is impervious to evidence that is contrary to their belief. Having this understanding, says Coltheart, allows a more scientific approach, because in many cases the delusional state is a result of damage suffered to the right side of the brain. There is always a "but" when it comes to how the brain works, however, and this case is no exception. "Across a range of delusions the answer sometimes is right hemisphere brain damage but it isn't always. So our choice is to say, we'll just stick to delusions that are clearly due to brain damage, or we'll be more ambitious and try and apply this two-factor approach, even to cases where we don't think the effect is due to brain damage," says Coltheart. This is why mental illness is so difficult to pin down, as it seems that many of these illnesses manifest from the extremes of an ability that we all have: belief formation. Coltheart adds that they are a long way off from a complete theory, but he does think that people suffering from delusions have an impairment of their system for evaluating beliefs.

Coltheart's theory of not being able to control the evaluation of beliefs may be consistent with one particular social disorder. How we present ourselves to society everyday, and how think we appear to other people seems to be an important factor in human relations, and many studies have shown how the face and body are crucial to how we judge other people. Take the little known, though not rare, disorder of Body Dysmorphic Disorder (BDD), where proper categorization is still contested by doctors. According to one definition, people with BDD are excessively preoccupied with an imagined or slight defect in their appearance. As a result, social interactivity and functioning are significantly impaired, causing distress. Researchers agree that BDD does not meet the criteria of other bodily-related disorders, such as anorexia nervosa, but it can have equally devastating effects, as BDD can lead to self imposed isolation and eventual suicide. Katherine Phillips, in her book Broken Mirror, describes cases of self-surgery that patients turn to in desperation, with predictably horrendous results. In one example, a person who was unhappy with the shape of their nose cut it open and replaced their own cartilage with chicken cartilage. BDD has a long history, and Phillips has found 100-year-old records that accurately describe BDD behavior patterns.

Ramachandran claims that: "brains are essentially model-making machines. We need to construct useful, virtual reality simulations of the world that we can act on." Both Stephen Pinker and Ramachandran claim that society is what ultimately shapes the way in which we think, and the way that we model the world for our own understanding. They also seem to agree that human behaviors are for an evolutionary purpose; survival as a species, say. The plasticity of the brain makes humans capable of change and adaptability, but it also means that there is a chance that this characteristic might work against us. In this respect, the adaptive potential within the brain goes pear shaped. In the case of BDD a person becomes overly obsessed by the way society expects them to present their external appearance. It is interesting to note that BDD nearly always begins in adolescence. Neuroscientists agree that the way the brain becomes wired when we "learn" something new is not the same for everyone. That is, if I learn the meaning of the letter "B" and everything associated with the letter "B", my brain doesn't care through what neural networks it passes, so long as the meaning of "B" is clear to me. Subsequently, it's possible that in the process of learning something as a child we might become more prone to believing one thing more than another person would.

Coltheart describes how a person might believe that aliens have abducted them because as they awoke from sleep they felt paralyzed and they felt as though they were floating up to the ceiling. In his study, participants explained that these "abductions" always took place in the morning when the subject was waking. Coltheart explains that these sensations are called hypnagogic hallucinations and they are experienced by 30 percent of the population. But the question is why the subjects were so willing to believe that they are being abducted over any other available explanation. "In this study, everybody who had the alien abduction delusion´┐Ż also had new age beliefs throughout their life. So they are willing to accept the possibility of alien abduction; I wouldn't be," said Coltheart.

So, while you can explain to a person who holds such beliefs that there are other explanations, it is unlikely that you will shake their belief that it was in fact aliens that abducted them. Their model of the world somehow includes Earth visiting aliens as a real possibility. This type of thinking can be related to religious beliefs as well, and because religions have such a long tradition and such devout followers, the delusion is reinforced tenfold. In reality, however, the religion is no more testable than other delusions. It might be comforting to know that Ramachandran considers the brain to be very plastic and pliable, so a person changing their beliefs over time is not entirely impossible.

There is still much to learn about the brain, but if the examples above are any clue, then we know that many of the beliefs that we hold have developed over a long period of time. As Ramachandran says, brains are model-making machines that ultimately determine how we view and behave in the environment that we find ourselves in, and our beliefs are a product of this model. It is important, then, that we feed this model-making machine with the right information, which does not include teaching children belief systems that cannot be verified or tested by any available means. If society's goal is to avoid people forming beliefs that are not grounded in reality, beliefs that are impervious to evidence, then why would we deliberately set out to teach a system that is itself impervious to evidence? Like the person who still feels their limb after it has been removed, once learned and integrated into the neural networks, these false beliefs are hard to shake, and will continue to guide an individual's thinking for a long time.