BBC在线收听下载:大脑扫描或将能确诊抑郁症

Psychiatrists have struggled with their diagnoses of depression; patients often present with overlapping symptoms. But researchers have made a breakthrough. In a new study published in Psychological Medicine, discovery which shows a distinct differences in the brain scans of people suffering different types of depression. Nance Haxton has more. At least one in five australians will be affected by a major depressive disorder at some time in their lives. It's a complex condition to identify，but researchers are now a step closer using medical imaging techniques commonly known as MRIs. Black Dog Institute professor Gordon Parker says it's a significant breakthrough. The study I think is more distinctly informative in telling us that there at least two key types of depression. One is the very biological depression which we call 'melancholia', and where we do need to be able to identify this condition so that people with it can be properly treated. I suppose another analogy would be looking at diabetes；for type one diabetes we know that most people are going to need insulin，for type two diabetes you probably use a non-drug strategy diet and exercise and loss of weight. And therefore we need better ways of separating out the biological type of depression, melancholia, from the other conditions. And particularly when we know the cause and the regions of the brain that affect it，this is an opportunity for developing a more appropriate treatments. I think it builds an increasingly clearer story in terms of where the problems lie in the brain when people go into the 'black dog' melancholic depression.

Researchers for this study conducted MRI scans on people diagnosed with depression while they watched happy and sad movies. What they discovered is that there are very distinct neurobiological changes in different parts of their brains，depending on which type of depression they had. Neuroscientist and study leader Dr.Christine Guo says it's hoped their findings will lead to better diagnostic tests. If can better diagnosing people for this underlying cause of their depression symptoms，we should be better treat them in the future. And hopefully that the treatment will be more successful? Exactly yeah,because it would be more targeted，or you could call it personalised medicine for a psychiatrist. And this is the start of that new approach I suppose? Yeah exactly，yeah，yeah. To sort of shift away from a symptom-based diagnosis in psychiatry，which you know has been in the field forever.

Group leader Dr Micheal Breakspear says the findings will help doctors break through the often overlapping symptoms that people with depression present. They range from sad mood，low energy to poor sleep. Each one is a potential clue that can lead to doctors identifying the underlying cause of their illness. A number of our recent brain imaging studies have found distinct sub-types of patterns of activity in the brain for people with depression. Depression is really a symptom；it's a symptom of low mood，loss of interest，there is other symptoms，and what have been doing in psychiatry is just classifying people into disorders based on their symptoms. But as imaging technology has advanced, we are now at the point where we can find distinct underlying differences in the brains of people，that we know from other studies respond differently to different types of medication.

The joint study published in Psychological Medicine was carried out by QIMR Berghofer Medical Research Institute，the university of New South Wales and the Black Dog Institute. while it may still be years before the diagnostic tools are ready for more general use. Professor Parker says these findings are an important step towards more effective treatment of depression. It sort of advances are clinical observation that we've long known for over 2,000 years that there was this depression called melancholia or the black dog. But its origins have been debated for years，a long period of time. It was thought to be certain neuro-transmitters and there have been multiple other causes that have been suggested. But neuroscience,in the last decade in particular，is moving to a model of looking at parts of the brain that are no longer connected, or they become disconnected during episodes of illness，and this study not only shows that people with melancholia have certain disconnections in the brain that people with non-melancholic depression and normal people don't show，even when depressed，it points at the areas of the brain that are involved and tells us something as to the actual causal process where things go wrong when people are in episode. And ideally that will lead to better treatment.