时差N小时 抑郁可能有利于进化(上)（在线收听）

Feeling down? You're not alone.

你有感到很失落吗?不只你这样。

If depression seems pretty common, it is.

抑郁看起来很普遍，事实上也是如此。

One in every ten adults suffers from depression.

每十个成年人里就有一个会患有抑郁症。

And that's what has scientists puzzled.

这让科学家们感到不解。

If depression is a detrimental condition, why is it so rampant in the population?

如果抑郁对身体有害，那么为什么人群中抑郁症患者如此之多呢?

Some scientists think they may have the answer.

一些科学家认为他们已经找到了答案。

Depression may have an evolutionary benefit.

抑郁也许对进化有好处。

It may improve one's chances of fighting off infection.

它能提高人体免疫力。

Scientists have known that depressed people display an immunoactive condition known as inflammation,

一些科学家发现抑郁症人群体内会产生免疫活性，也就是炎症，

even when they are not infected.

即便他们未受到感染时也会如此。

For several years they have been finding that genes linked to depression also affect the function of the immune system.

几年来，科学家们逐渐发现与抑郁有关的基因也会影响免疫系统的功能。

Stress, which can lead to depression, also modifies the immune system.

同样会导致抑郁的压力因素也会改变免疫系统。

These findings suggested that depression was somehow linked to the body's ability to fight disease.

从某种程度上讲，这些调查结果表明抑郁与人体免疫力有关。

Some scientists now propose that depression might have had an evolutionary advantage in the days before modern medicine and antibiotics.

一些科学家提出早在现代药物和抗生素出现之前，抑郁就可能能够给进化带来好处。