In the United States, close to 10 percent of adults struggle with depression. 在美国，有近百分之十的成人受忧郁症之苦。

But because it's a mental illness, it can be a lot harder to understand than, say, high cholesterol. 但因为忧郁症是种心理疾病，要了解它会比高胆固醇之类的困难许多。

One major source of confusion is the difference between having depression and just feeling depressed. 一个主要困惑是抑郁症和单纯情绪低落之间的区别。

Almost everyone feels down from time to time. 几乎每个人都会偶尔心情不好。

Getting a bad grade, losing a job, having an argument, even a rainy day can bring on feelings of sadness. 考试考差、失业、吵架，甚至下雨天也会引起悲伤的感觉。

Sometimes there's no trigger at all. It just pops up out of the blue.  有时候甚至没有诱因，难过的感觉就那样突然冒出来。

Then circumstances change, and those sad feelings disappear. 然后情况改变，那些悲伤的感觉也消失了。

Clinical depression is different. It's a medical disorder, and it won't go away just because you want it to. 临床忧郁症不同，它是一种疾病，不会因为你要它消失就消失。

It lingers for at least two consecutive weeks and significantly interferes with one's ability to work, play, or love. 低落的情绪会持续至少两周，且会严重影响一个人工作、玩乐或爱人的能力。

Depression can have a lot of different symptoms: 忧郁症可能会有许多不同的病征：

a low mood, loss of interest in things you'd normally enjoy, changes in appetite, 情绪低落、对平常喜欢的事物失去兴趣、胃口改变、

feeling worthless or excessively guilty, sleeping either too much or too little,  觉得自己没价值或过度罪恶感、睡太多或太少、

poor concentration,restlessness or slowness, loss of energy, or recurrent thoughts of suicide. 注意力不集中、焦虑或迟滞、失去活力，或反覆出现自杀念头。

If you have at least five of those symptoms, 如果你有其中至少五个症状，

according to psychiatric guidelines, you qualify for a diagnosis of depression. 根据精神病学指南，你就符合忧郁症诊断。

And it's not just behavioral symptoms. Depression has physical manifestations inside the brain. 忧郁症不仅是行为上的症状，在大脑中也有具体表现。

First of all, there are changes that could be seen with the naked eye and X-ray vision. 首先，有能用肉眼及X光观察到的变化。

These include smaller frontal lobes and hippocampal volumes. 这些包含额叶和海马体积缩小。

On a more micro scale, depression is associated with a few things: 更微观的水平上，忧郁症和几样东西有关：

the abnormal transmission or depletion of certain neurotransmitters,  特定神经传导物质的反常传递或减少，

especially serotonin, norepinephrine, and dopamine; 特定神经传导物质的反常传递或减少，

blunted circadian rhythms, or specific changes in the REM and slow-wave parts of your sleep cycle; 生理时钟变迟钝，或睡眠周期中快速动眼期和慢波期的明显改变；

and hormone abnormalities, such as high cortisol and deregulation of thyroid hormones. 以及荷尔蒙失调，例如皮质醇过高和甲状腺激素异常。

But neuroscientists still don't have a complete picture of what causes depression. 不过神经科学家对忧郁症的成因仍未完全理解。

It seems to have to do with a complex interaction between genes and environment, 它似乎和基因与环境间的复杂交互作用有关，

but we don't have a diagnostic tool that can accurately predict where or when it will show up. 但我们尚未有精准预测忧郁症发作时地的诊断工具。

And because depression symptoms are intangible, it's hard to know who might look fine but is actually struggling. 而且因为忧郁症病征捉摸不定，很难知道哪些看起来好好的人其实正在遭受忧郁症。

According to the National Institute of Mental Health, 根据美国国家心理卫生研究院的研究，

it takes the average person suffering with a mental illness over 10 years to ask for help. 一般心理疾病患者要拖十年以上才会寻求协助。

But there are very effective treatments.Medications and therapy complement each other to boost brain chemicals. 但忧郁症有十分有效的治疗方法。药物和疗法相互辅助来激发脑内化学物质的生成。

In extreme cases, electroconvulsive therapy, which is like a controlled seizure in the patient's brain, is also very helpful. 在极端案例中，电疗法，即像是一种在患者脑部控制痉挛发作的方法也极有帮助。

Other promising treatments, like transcranial magnetic stimulation, are being investigated, too. 其它备受看好的治疗方法，比如穿颅磁刺激法，也在研究当中。

So if you know someone struggling with depression, 如果你认识某个遭受忧郁症的人，

encourage them gently to seek out some of these options. 温柔地鼓励他们寻求一些方法。

You might even offer to help with specific tasks, 你甚至可以帮忙做一些事，

like looking up therapists in the area or making a list of questions to ask a doctor. 比如搜寻附近的心理治疗师，或是列出要问医生的问题清单。

To someone with depression, these first steps can seem insurmountable. 对一个有忧郁症的人来说，第一步可能难以跨越。

If they feel guilty or ashamed,point out that depression is a medical condition, just like asthma or diabetes. 如果他们感到罪恶或羞愧，指出忧郁症是疾病的事实，它就像气喘或糖尿病一样。

It's not a weakness or a personality trait, and they shouldn't expect themselves to just get over it, 这不是懦弱或人格特质，他们不该指望自己就能好起来，

any more than they could will themselves to get over a broken arm. 就像他们也没办法用意志力让断臂复原一样。

If you haven't experienced depression yourself, avoid comparing it to times you've felt down. 如果你自己不曾得过忧郁症，避免拿忧郁症和心情不好作比较。

Comparing what they're experiencing to normal, 将他们的遭遇和一般短暂的难过情绪相提并论，

temporary feelings of sadness can make them feel guilty for struggling. 会让患者对自己的挣扎感到罪恶。

Even just talking about depression openly can help. 就算只是公开讨论忧郁症都有帮助。

For example, research shows that asking someone about suicidal thoughts actually reduces their suicide risk. 举例来说，研究显示，询问一个人有无自杀念头真的能降低他们自杀的风险。

Open conversations about mental illness help erode stigma and make it easier for people to ask for help. 开诚布公地讨论心理疾病有助消弭污名，并让人们更容易寻求协助。

And the more patients seek treatment, the more scientists will learn about depression, and the better the treatments will get. 而有更多的病患寻求治疗，科学家就能越了解忧郁症，治疗方法就会变得更进步。