I may appear to be happy and animated all the time, pun intended.

我可能看起來很開心也很熱烈，這是一語雙關 (animated 也指動畫的)。

But some days I fall into a slump.

但有時候我會陷入低潮。

We all do. It's a part of life.

我們都會如此，那是人生的一部分。

These feelings are real, and the effects aren't always just mental.

那些感覺很真實，而它會造成的影響不會只有心理層面。

You can actually feel them in a physical sense, too.

事實上你可以從生理層面感覺到那些感覺。

But how? And why? Let's find out.

但是怎麼發生的？又是為什麼？我們來看看吧！

Depression can be the result of a chemical imbalance in the noggin.

「憂鬱」是大腦化學物質失衡所造成的結果。

Chemicals called neurotransmitters aid in sending messages to different nerve cells in your brain.

稱為神經傳導物質的化學物質，有助於在腦子裡不同的神經細胞間傳遞訊息。

Some neurotransmitters can control your mood.

有些神經傳導物質可以控制你的情緒。

When you're depressed, these neurotransmitters might not be functioning properly, causing severe changes in mood.

當你憂鬱時，神經傳導物質可能運作失衡，才會造成情緒的劇烈波動。

Depression can be caused by things like stressful life events, certain medications, death of a loved one, hormonal changes, and of course, caused by faulty mood regulation in the brain.

憂鬱的形成原因包含令人壓力很大的人生經歷、藥物、摯親過世、荷爾蒙的變化，還有當然，源於腦中情緒的調節失常。

One part of the brain affected by depressions is called the hippocampus.

腦中操控「憂鬱」的部份稱作海馬迴。

The hippocampus processes long term memory in recollection. It also registers fear, and it is actually smaller in people with depression.

海馬迴處理記憶中的「長期記憶」以及恐懼，而且事實上，它在憂鬱的人的腦內會變得比較小。

Ongoing exposure to stress impairs nerve cell growth in this part of the brain.

持續處於壓力之下會損害神經細胞在此這部分的生長。

Not only can depression have you feeling down, but it can actually physically affect parts of your body other than the brain.

憂鬱不但會讓你感覺情緒低落，也會在生理上影響你腦袋以外的身體部位。

Chronic fatigue, insomnia, over-sleeping and general aches and pain are just a few examples.

慢性疲勞、失眠、過度睡眠、還有疼痛只是其中幾個例子。

Pain threshold can be altered by abnormal functioning of the brain's neurotransmitters like serotonin, making people with depression more sensitive to pain.

痛苦的源頭可能會被腦中神經傳導物質，比如說血清素的不正常運作而影響，讓憂鬱的人對於疼痛更加敏感。

Another interesting physical change that can come with depression is eyesight.

另外一種伴隨憂鬱而生的有趣生理改變在於視力。

Recent studies show that the retinas of depressed patients were actually less sensitive to contrast.

近期的研究報告顯示，憂鬱患者的視網膜對於對比較不敏感。

Contrast vision relies on cells that in turn rely on dopamine.

視覺對比所依賴的細胞需依賴多巴胺。

People with depression are often shown to have less dopamine, which is important for drive and attention.

憂鬱的人顯示出較為少量的多巴胺，而它對於集中注意力很重要。

These findings are still relatively new but very interesting.

這些研究發現都還很新，但是很有趣。

One unfortunate problem that comes with depression is the fact that it can actually increase your risk of physical illness.

另一個伴隨憂鬱而發生的不幸問題是，它確實會增加你身體上疾病的風險。

Stress hormones are increased which can lead to more problems.

壓力荷爾蒙會增加，導致更多的毛病。

When we're stressed, our immune system's ability to fight off antigens of foreign bodies is reduced, making it more difficult to fight off infections.

當我們壓力很大時，我們免疫系統對抗外來抗原的能力會減低，讓抵抗感染變得更加困難。

Corticosteroid, a stress hormone, can actually suppress the overall effectiveness of the immune system by lowering the amount of lymphocytes, which are cells that destroy the bodies of invaded viruses.

皮質類固醇，一種壓力激素，會抑制整個免疫系統的效率，因為它會降低淋巴的量，也就是負責消滅侵入人體之細菌的細胞。

Did you know the seasons can actually affect your mood?

你知道季節會影響你的情緒嗎？

It's called seasonal affective disorder.

這叫做季節性情緒失調。

When there's less daylight your, brain can increase neurotransmitters like melatonin.

當日光變少，你的腦部會增加一些激素，比如說褪黑激素。

More daylight, and your brain will produce more serotonin.

而日光越多，你的大腦就會產生越多的血清素。

In the fall and the winter where there're shorter days and less daylight, your body might produce less serotonin and more melatonin.

在秋冬之際，當白天比較短、日照也比較少時，你的身體會產生較少的血清素，與較多的褪黑激素。

This imbalance can set up the brain for depression to some people who react to seasonal changes.

這種不平衡讓那些對季節變換產生反應者的大腦產生憂鬱。

Exposure to more light can help people maintain this chemical balance.

多照點光可以幫助人們維持化學物質的平衡。

If you or someone you know is depressed, please seek help immediately.

如果你或者你認識的人正處於憂鬱狀態，請馬上尋求幫助。

You can check the links below for some online resources.

你可以查看下面的連結尋求線上資源。

Going to the doctor, seeing a therapist and thinking positively can work wonders

看個醫生、看個治療師，以及正面思考也可以產生奇蹟。

So please don't be afraid to get out there and ask for help.

所以請不要害怕去尋求幫忙。

What are some things in life that make you happy?

什麼東西可以讓你快樂？

Let's set up a positivity train in the comments.

我們在底下的留言處開始正面的討論串吧！

If you see someone with a similar interest in the comments, strike up a conversation!

如果你看到誰在回應跟你擁有類似的興趣，開啟一個對話吧！

Or you can simply tell us what should we talk about next.

或者你也可以告訴我們你希望下次討論什麼。

And if want even more Life Noggin, check out this episode on "The Science of Happiness," and follow us on Facebook and Twitter.

如果你還想看更多的 Life Noggin，看看這集的「快樂的科學」，並在臉書與推特上面追蹤我們。

Links are below.

連結就在下方。

I'm Blocko. This has been Life Noggin.

我是 Blocko，這裡是 Life Noggin。

Don't forget to keep on thinking.

別忘了繼續思考！