alogia

Biological Psychiatry: Endless fascination; indeterminate value

 Biological Psychiatry, Featured, Psychiatry  No Responses »
May 022011
 
phrenology

There is no doubt that our growing knowledge regarding the biological origin of psychiatric illnesses is a source of endless excitement. Since the time of the Spanish neuroscientist Santiago Cajal, discoveries in neuropathology have helped establish the authenticity of a diagnoses ranging from epilepsy to ADHD, and so given science another valuable victory over centuries of ridicule and stigma. More recently, advances in functional magnetic resonance imaging (fMRI) have provided us with a new, essentially non-invasive total for studying psychiatric illness on a biological level. It is hoped by many that these techniques will allow us to eventually fully understand the pathophysiology of a group of illnesses that have, until recently, been outside the realm of true scientific study.

As tends to be the case with any new technology, there are many who have their doubts. This ranges from the extremes of the anti-psychiatry movement, which continues to favour a “dualistic approach”, arguing that mental illness is a property of the ineffable soul, rather than an illness of the brain. Of this we shall speak no further, as it falls outside what this blog will generally consider to be valuable enquiry. Of considerably more value are the legitimate concerns of those who, whilst acknowledging that all psychiatric diseases possess an organic basis, question our ability to accurately ascertain these origins using present technology and methodology. William Uttal, in his book “The New Phrenology: The Limits of Localizing Cognitive Processes in the Brain” argues that we need to more clearly examine the limitations of modern techniques, furthermore implying that the current obsession with localisation is a form of “neophrenology” – or, other wise put, an echo of a once popular pseudoscientific practise, were conclusions about the state of development of specific brain areas were made based on the size of the overlying cranial bone!

Whilst I think that this claim (which is perhaps something of a caricature of Uttal’s actual thesis) is somewhat harsh, it is true that fMRI does have several limitations, which have been well described in the literature. What I wish to focus on in this piece is not the technical difficulties, but rather what I consider to be an inherent methodological problem in using fMRI as a diagnostic tool, which is perhaps the endpoint that is most hoped for by psychiatrists in cognitive neuroscience.

The first problem (which, incidentally, did not escape Uttal’s attention either) relates to weakness within the psychiatric taxonomy. Anyone who has closely followed the development of the fifth diagnostic and statistical manual of mental disorders will be aware of how much classification has changed (and will probably continue to change) within psychiatry. Until now, such classifications have been almost entirely based on phenomenological data, which has allowed us to group syndromes according to commonly occurring symptom clusters. These syndromes initially began as simple descriptions of mentally ill patients, and patients that behaved in similar ways were classified as having the same condition.  This lead to several errors, owing to the fact that several conditions, when viewed for a brief time, look largely the same – even experienced psychiatrists struggle to differentiate between the mania of a patient with bipolar mood disorder and the psychosis of the schizophrenic. Subsequently, syndromes were refined based on further assessment of age of onset, manner of progression and other longitudinal factors. Modern classification systems, such as the DSM-IV (diagnostic and statistical manual of mental disorders, fourth edition), use essentially the same criteria, albeit by employing enormous databases, pooled from studies conducted all over the world. Despite this, significant controversy remains, and most psychiatrists agree that we are some way from achieving anything like a “definitive” classification.

It is worth remarking how different this process is from what has happened in other fields. Take lesions of the cardiac valves, for example. Initially, they were probably also only described according to symptoms, which would have been largely indistinguishable from those of several other causes of heart failure. However, with the advent of instruments as simple as the first, rudimentary “stethoscopes”, one could directly observe the presence of heart murmurs, which could help determine not only the presence of a heart lesion, but, with some skill, the precise valve that was affected, and even the degree to which it was affected!

It is difficult to resist the temptation to suggest that fMRI will do for psychiatry what the stethoscope did for cardiology, but clearly things are not that simple. Going back to classification – psychiatry has a unique problem in that the vast majority of its conditions have been defined based on symptoms, rather than objective pathology. Again, compare cardiology, which has some syndromes (like heart failure, for example), but several diseases, which have been defined based on their anatomical origin and pathophysiology. This is crucial to successful treatment – two different valve lesions may present in the same way, but treating them in the same way is seldom appropriate. Few patients will appreciate an aortic valve replacement when the their disease is clearly confined to the mitral…

Is this the case in psychiatry? I would argue that we don’t know, but that we should probably try and find out before we decide how much diagnostic faith we put into neuro-imaging.  Evidence suggests that patients who present with symptoms of depressed mood, most of the day, every day, along with a prescribed number of other classic symptoms, can be classified as having “major depressive disorder”. This, in turn, can be regarded as a condition that is in most cases responsive to treatment with antidepressants and psychotherapy, either separately or in combination.

In recent years we have successfully described a range of findings, both on neuroimaging and neuropathological study, that appear to be common in patients with depression. Would it not then be reasonable to test patients for these changes, in order to determine whether or not they really have “depression”, rather than some other condition masquerading in its guise? How then, would we respond to such a patient? Would it be appropriate to deny them treatment? Would we label them as being malingerers? These could all be true, but another potential answer needs to be addressed.

When we begin to search for the neurological underpinnings of a disease, we begin with a syndrome. Assume we have a hundred patients with clinical depression on whom we conduct fMRIs, and so determine which features appear to be most common. Lets further assume the unlikely case that all of these patients have at least one or more finding in common, which will then form our new “definition” of what it means to have depression.

All we will really have done in such a study is to define one possible cause of a syndrome. As the case of heart failure and valve lesions have taught us – there could be several others. Perhaps even several of the patients in this study have developed depression due to a different mechanism, and only incidentally display some of the same findings as the rest of the group. And what of our patient? Who is to say that she herself is not the victim of some hitherto undescribed condition, causing her to develop the symptoms of depression on the basis of a unique neuropathological mechanism?

Things in psychiatry are not as clear as in cardiology (or gastroenterology or pulmonology or any other field in medicine for that matter). The functions of the brain are not intuitively elucidated from its anatomy, and although we must recognise that it is the starting point for all mental illness, it is not necessary to assume that it should form the starting point for diagnosis. Some would argue that a syndromic classification has its own weaknesses, a claim to which we must acquiesce – but is it not ultimately the method that would best benefit our patients, at least given our current knowledge?

If a patient comes to a psychiatrist feeling depressed, anhedonic and suicidal, she needs help, whatever might really be going on. A psychiatrist cannot claim that he only has a role to play when a “true” psychiatric illness can be detected – after all, if we are to fully reject dualism, we must acknowledge that even the most minor aberration of psychological function finds its origin in the brain, and since this is the organ we claim to treat, we cannot ignore it. It may sound like I completely reject the role of fMRI, and perhaps even biological psychiatry as a whole. But anyone who has bothered to explore my blog would see this is unlikely – indeed, I have dedicated an entire section to this subject. And next week, I hope to address the issue of treatment response. Here, we will perhaps be exploring an area where fMRI may truly come into its own, with potentially revolutionary consequences.

 

Religion as an exclusion criteria: an issue of sensitivity vs specificity?

 Philosophy of psychiatry  Comments Off
Apr 272011
 

In its simplest form, a delusion is a false belief that is held in the absence of evidence. Psychiatrists have generally found it necessary to include the disclaimer that religious beliefs (which, being faith based, are invariably held in the absence of evidence) should be protected from such a label, so long as they remain reasonable within the boundaries of the specific religious subculture. This disclaimer is a good thing – certainly, without it, literally billions of comparatively sane individuals would have to be regarded as delusional. The fact that religion should rely on such a proviso is in itself somewhat ominous – one would hope that a belief system would be differentiable from psychosis on intrinsic merits, rather than by forced exclusion. However, what I wish to focus on today is the more pertinent issue to psychiatry. By using religion as an exclusion criteria, we greatly increase the specificity of our diagnosis by excluding the hordes of well-adjusted faithful who would certainly have to be regarded as “false-positives” otherwise. As any statistician will tell you, increased specificity always has a payoff, and that is that you encounter decreased sensitivity. More simply put – our increased specificity means that some people who are indeed ill will go undiagnosed, by virtue of this broad exclusion.

The natural response to this is to highlight an essential component of the exclusion – religious ideas are only excluded from being called “delusions” when they are out of keeping with the normally accepted behavior of the subculture. This, however, is not a complete solution, owing to several inherent ambiguities. Firstly, it is not always clear when someone has exceeded the norms of his or her subculture, especially in less extreme cases. A patient I recently saw comes to mind – she was a 19 year old girl who, together with her mother, had been diagnosed with folie a deux – a shared delusion. They were brought to the psychiatry clinic by the girls’ grandmother, who reported what she regarded as “over-religious behaviour”. Specifically, the mother and daughter would spend several hours in prayer each day, and engage in intermittent fasts as a way of showing their devotion.

Of concern in this case was the fact that the relevant subculture in this instance – a relatively small local denomination – did not regard this behaviour as abnormal. In fact, both the girl and her mother had achieved a degree of status through their devotion, and were regarded as something to which others should aspire. By definition, then, their behaviour should not have been regarded as delusional, despite the fact that both patients were becoming increasingly socially isolated, and had ceased to function effectively in any other aspect of their lives. As it happened, the diagnosis was made despite the positive views of their religious peers, and the patients were admitted for further treatment. They later showed signs of severe psychosis, and responded well to treatment. What this case illustrates, however, is the difficulty in relying on the views of the subculture in deciding whether religious ideas are “delusional” or not. Sometimes the most deluded are in fact the ones held in the highest esteem.

The concept of a shared delusion brings us to the second point of concern – specifically, the problem of a “mass delusion”. Again, I shall make my point by referring to a case. I spoke to the daughter of a patient who was being treated as an outpatient for paranoid schizophrenia. When I asked how her mother was doing, the patient replied that although she was still very paranoid, she at least seemed happy, owing to her involvement in a new church that had started in the area. This church seemingly placed great emphasis on “spiritual experiences”, including visions and prophecies. That a schizophrenic patient should feel comfortable in such an environment seems unsurprising – but what do we say of the rest of the congregation? If one of them were to have their first contact with mental health services, would their behaviour be regarded as normal, owing to its concordance with the rest of the subculture? Again, this could be inappropriate, as it could be that the subculture itself has become floridly delusional.

Making these distinctions are difficult, and can often involve exploring very sensitive territory. Personally, I find myself again struck by the ability of religion to confound and complicate, and can offer little insight into how best to approach these issues. Perhaps one day we can drop such an exclusion without totally sacrificing specificity. Until then, let us hope that those undiagnosed are able to achieve a degree of comfort within their specific subcultures – a not unlikely prospect given the enormous degrees of faith of which the mentally ill are capable.

Religion as an exclusion criteria: an issue of sensitivity vs specificity?

 Philosophy of psychiatry  Comments Off
Apr 272011
 

In its simplest form, a delusion is a false belief that is held in the absence of evidence. Psychiatrists have generally found it necessary to include the disclaimer that religious beliefs (which, being faith based, are invariably held in the absence of evidence) should be protected from such a label, so long as they remain reasonable within the boundaries of the specific religious subculture. This disclaimer is a good thing – certainly, without it, literally billions of comparatively sane individuals would have to be regarded as delusional. The fact that religion should rely on such a proviso is in itself somewhat ominous – one would hope that a belief system would be differentiable from psychosis on intrinsic merits, rather than by forced exclusion. However, what I wish to focus on today is the more pertinent issue to psychiatry. By using religion as an exclusion criteria, we greatly increase the specificity of our diagnosis by excluding the hordes of well-adjusted faithful who would certainly have to be regarded as “false-positives” otherwise. As any statistician will tell you, increased specificity always has a payoff, and that is that you encounter decreased sensitivity. More simply put – our increased specificity means that some people who are indeed ill will go undiagnosed, by virtue of this broad exclusion.

The natural response to this is to highlight an essential component of the exclusion – religious ideas are only excluded from being called “delusions” when they are out of keeping with the normally accepted behavior of the subculture. This, however, is not a complete solution, owing to several inherent ambiguities. Firstly, it is not always clear when someone has exceeded the norms of his or her subculture, especially in less extreme cases. A patient I recently saw comes to mind – she was a 19 year old girl who, together with her mother, had been diagnosed with folie a deux – a shared delusion. They were brought to the psychiatry clinic by the girls’ grandmother, who reported what she regarded as “over-religious behaviour”. Specifically, the mother and daughter would spend several hours in prayer each day, and engage in intermittent fasts as a way of showing their devotion.

Of concern in this case was the fact that the relevant subculture in this instance – a relatively small local denomination – did not regard this behaviour as abnormal. In fact, both the girl and her mother had achieved a degree of status through their devotion, and were regarded as something to which others should aspire. By definition, then, their behaviour should not have been regarded as delusional, despite the fact that both patients were becoming increasingly socially isolated, and had ceased to function effectively in any other aspect of their lives. As it happened, the diagnosis was made despite the positive views of their religious peers, and the patients were admitted for further treatment. They later showed signs of severe psychosis, and responded well to treatment. What this case illustrates, however, is the difficulty in relying on the views of the subculture in deciding whether religious ideas are “delusional” or not. Sometimes the most deluded are in fact the ones held in the highest esteem.

The concept of a shared delusion brings us to the second point of concern – specifically, the problem of a “mass delusion”. Again, I shall make my point by referring to a case. I spoke to the daughter of a patient who was being treated as an outpatient for paranoid schizophrenia. When I asked how her mother was doing, the patient replied that although she was still very paranoid, she at least seemed happy, owing to her involvement in a new church that had started in the area. This church seemingly placed great emphasis on “spiritual experiences”, including visions and prophecies. That a schizophrenic patient should feel comfortable in such an environment seems unsurprising – but what do we say of the rest of the congregation? If one of them were to have their first contact with mental health services, would their behaviour be regarded as normal, owing to its concordance with the rest of the subculture? Again, this could be inappropriate, as it could be that the subculture itself has become floridly delusional.

Making these distinctions are difficult, and can often involve exploring very sensitive territory. Personally, I find myself again struck by the ability of religion to confound and complicate, and can offer little insight into how best to approach these issues. Perhaps one day we can drop such an exclusion without totally sacrificing specificity. Until then, let us hope that those undiagnosed are able to achieve a degree of comfort within their specific subcultures – a not unlikely prospect given the enormous degrees of faith of which the mentally ill are capable.