Detecting disease before it begins

Do you know any psychotics? How do they smell? An article in Seed magazine talks about using a faulty sense of smell to predict who might go on to develop schizophrenia, obsessive-compulsive disorder or any number of other mental illnesses (http://www.seedmagazine.com/news/2006/12/test_sniffs_out_mental_illness.php). Mental illness is associated with a decline in frontal lobe activity (the front bits of the brain where our personality basically sits) which in turn manifests as an inability to identify certain odors correctly. From a scientific perspective, this all sounds very interesting but it made me wonder. My dad never could smell much and he did go on to develop a form of dementia that was ultimately his un-doing. A very good friend of mine, in her mid 40s also cannot smell. Not a thing. Is she about to turn psychotic on me or is the faulty whiffer due to something unrelated to her frontal lobes. Maybe her nose for instance? I have long been an advocate for understanding very early disease stages, before a disease is even detectable, in the hopes of offsetting progression with either medication or behavior changes, or both. I think we should be much better at mapping the temporal nature of disease for individuals as well as populations. However, when we do find what we believe might be a precursor to illness, how should we in the medical field respond? Develop a 'biomarker' that can be used as a diagnostic test? Or, just use the information to understand the early disease markers before we get anywhere near a diagnostic? The issue goes beyond science at this point and into ethics. How can we in good conscious administer a test for, let's say, early-onset Alzheimer's, when we have no way to prevent the inevitable progression? We would have folks running around just waiting for the day they forget more than the shopping list (that's normal-right?), in fact, waiting for the shoe to drop. We want predictive, preemptive measures to improve our health outlook. But science has to take care to lead us appropriately and engage the bigger picture when we know more than perhaps we really want to. Health researchers should include multi-disciplinary perspectives at all levels of research that will include ethicists (for the right/wrong questions), psychologists (for the mind-body aspects), physiologists (for the whole systems view, so often not represented these days) and carers (for the practical aspects of delivering sound advice and service). The list of interacting disciplines could grow long indeed when we add the value of social status, spiritual aspirations, spiral level (Spiral of Development from Graves' Spiral Dynamics theory--read Cohen and Beck's book 'Spiral Dynamics' for a modern and practical interpretation) and a host of others. In other words, when science gets deep and implications look profound, the only approach is an Integral Health approach. So back to that nose issue. Bad smelling skills might preclude you from a profession in perfumery, but it certainly doesn't mean psychosis is inevitable. The scientific study found an association between smell and mental illness, which does not imply causation. It is a factor to consider along with many others, if for example, Aunt Maud is acting a bit strange and you wonder whether she's losing it or just merely getting into the Christmas spirit. Which reminds me, I must go and get that tree. Always a real one in our house...if only for the smell.