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，然后可能会在一生中复发。一旦确诊，抑郁症会增加人们患其他疾病的风险，如糖尿病、心脏病和记忆问题。在我们的研究中，我们希望探索这样一种观点，即抑郁症和其他疾病是通过一种名为皮质醇的应激激素分泌增加而联系在一起的。我们认为，皮质醇分泌的增加在疾病实际发生之前会发生很多年。从理论上讲，皮质醇分泌增加可以解释为什么人们会变得抑郁，然后发展成相关的医疗条件。如果是这样的话，就有可能设计出新的治疗方法，通过在疾病显现之前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，有家族病史的年轻人在没有任何抑郁症或任何其他医学疾病的证据之前，就会分泌过多的皮质醇，从而增加患抑郁症的风险。如果我们的想法是正确的，那么我们预计同样的年轻人会有异常的证据，表明他们处于与抑郁症相关的医疗条件的风险中。例如，他们可能表现出处理葡萄糖的效率降低(易患糖尿病)，血管弹性改变(易患血管疾病)，以及称为海马体的大脑结构体积较小(易患记忆问题)。这就是我们将在本研究中测试的内容。

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.