Use of biomarkers to detect pre-symptomatic medical co-morbidity in young people at familial risk of depression

临床抑郁症通常发生在年轻人身上，然后可能在一生中复发。抑郁症一旦形成，就会增加人们患其他疾病的风险，比如糖尿病、心脏病和记忆力问题。在我们的研究中，我们希望探索抑郁症和其他疾病与一种叫做皮质醇的应激激素分泌增加有关的观点。我们认为皮质醇分泌的增加在疾病真正发生之前就已经发生了很多年。皮质醇分泌的增加理论上可以解释为什么人们变得抑郁，然后发展相关的医疗条件。如果是这样的话，就有可能设计出新的治疗方法，在疾病变得明显之前通过降低皮质醇来预防抑郁症及其医学并发症的发展。我们最近发现，有抑郁症家族史的年轻人患抑郁症的风险会增加，在他们有任何抑郁症或其他医学疾病的证据之前，他们会分泌过多的皮质醇。如果我们的想法是正确的，那么我们预计同样的年轻人也会有异常的证据，表明他们有患抑郁症的风险。例如，他们可能表现出葡萄糖处理效率下降（易患糖尿病），血管弹性变化（易患血管疾病），以及被称为海马体的大脑结构体积变小（易患记忆问题）。这就是我们将在本研究中进行的测试。

Clinical depression often develops in young people and can then recur over a lifetime. Once established, depression puts people at increased risk of other medical conditions such as diabetes, heart disease and memory problems. In our study we wish to explore the idea that depression and these other medical conditions are linked by increased secretion of a stress hormone called cortisol. We believe that the increase in cortisol secretion happens for many years before the illnesses actually occur. Increased cortisol secretion could theoretically account for why people become depressed and then develop the related medical conditions. If this is the case it might be possible to devise new methods of treatment which would prevent the development of both depression and its medical complications by lowering cortisol before the illnesses have become apparent.We have recently found that young people at increased risk of depression through having a family history of the illness secrete too much cortisol before they have any evidence of depression or any other medical illness. If our idea is correct then we would expect the same young people to have evidence of abnormalities suggesting they are at risk of the medical conditions linked to depression. For example, they may show decreased efficiency of handling glucose (vulnerability to diabetes), changes in the elasticity of blood vessels (vulnerability to blood vessel disease) and smaller volume of a brain structure called the hippocampus (vulnerability to memory problems). This is what we will test in the present study.