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Odds are, you've heard of Ritalin or Adderall.
你可能聽說過利他林或阿得拉。
They're both members of the class of drugs called stimulants,
它們都是興奮劑類的藥物，
and they're often prescribed to treat attention deficit hyperactivity disorder, better known as ADHD.
它們經常被用于治療注意力缺陷多動癥（ADHD）。
But stimulants and hyperactivity seem like a weird match.
但興奮劑和多動癥似乎是一對奇怪的組合。
If someone can't sit still, why would you give them more energy?
如果有人坐不住，為什么還要給他們更多的能量呢？
Like with a lot of other psychiatric treatments, the answer has to do with a chemical imbalance in the brain.
就像其他很多精神治療一樣，它的答案與大腦中的化學失衡有關。
The way stimulants affect that imbalance can reveal a lot about
興奮劑影響失衡的方式可以揭示很多內容：
what's really happening when you get distracted or hyperactive,
你在分心或極度活躍時，大腦會發生什么，
and what changes when you are focused and attentive.
你在專注專心某事時大腦又有什么變化。
It can also explain why, if people without ADHD take these meds,
它也能解釋沒有多動癥的人采用這些方法
they might not be getting the boost they think they are.
為什么沒有獲得他們以為的那種提升。
ADHD doesn't look exactly the same in everybody, but most of the symptoms fall under one main category:
每個人的多動癥表現并不完全一樣，但大多數癥狀都屬于一個主要類別：
executive functions, which are essentially the mental processes that help you get things done.
執行功能，它基本上是幫助你完成任務的心理過程。
These include the qualities that usually come to mind when people think of ADHD,
這些癥狀包括人們在思考多動癥時通常會想到的品質，
like focusing or remembering details.
比如專注或記憶細節。
But the symptoms can include problems with other things, too,
但是這些癥狀還包括其他方面的問題，
like organization, time management, and controlling your impulses and emotions.
比如組織、時間管理、控制沖動和情緒。
We haven't completely nailed down what's happening in the brains of people with ADHD,
我們還沒有完全確定多動癥患者的大腦情況，
because looking directly into people's brains, turns out it's pretty hard.
因為直接觀察人們的大腦很困難。
But one of the main ideas is the low arousal theory,
但有一個叫低覺醒理論的主要觀點
which basically says that people with ADHD have chronically underaroused brains,
基本講的是多動癥患者的大腦長期處于低興奮狀態，
and that stimulants help by increasing their arousal.
而興奮劑可以通過加快它的覺醒來幫助它。
To be clear, arousal in this context just means there less brain activity in certain regions.
需要說明的是，這種情況下的覺醒僅僅意味著某些區域的大腦活動減少。
When someone's brain is underaroused, it can mean their neurons aren't firing as much in certain regions,
當一個人的大腦未被充分喚醒時，可能意味著大腦某些區域的神經元沒有那么活躍，
or that some neurotransmitters, the chemicals that communicate signals between neurons, aren't flowing properly.
或者是一些神經遞質——神經元之間傳遞信號的化學物質——沒有正常流動。
According to the low arousal theory,
根據低覺醒理論的說法，
this leads you to look for new stimulation in your environment to jumpstart your neural activity.
這會讓你在自己的環境中尋找新刺激來快速啟動你的神經活動。
And from the outside, that looks like you're hyperactive or just inattentive.
外在表現為看起來過度活躍或漫不經心。
More specifically, the disorder has to do with where you find dopamine,
更具體地說，這種障礙與你找到的多巴胺位置有關，
a neurotransmitter related to the brain's pleasure and reward responses.
多巴胺是一種與大腦的愉悅和獎賞反應有關的神經遞質。
Generally, more dopamine translates to a greater feeling of reward.
一般來說，多巴胺越多，獎勵的感覺就越強烈。
When your dopamine levels are high, you just feel … good.
當你的多巴胺水平很高時，你會感覺…很棒。
One way to measure this is called the tonic dopamine level,
衡量它的一種方法叫做持續釋放多巴胺的水平
which is how much dopamine is kind of hanging out between your neurons already.
也就是你的神經元之間游離著多少多巴胺。
But there's also phasic dopamine, which is what your neurons release based on a stimulus
但還有一種階段性多巴胺，它是你的神經元根據刺激物釋放的，
anything from finishing your PhD thesis to noticing the pretty bird outside your window.
這種刺激從完成你的博士論文到注意窗外美麗的小鳥。
Both kinds of dopamine levels are important because they affect each other.
這兩種多巴胺水平都很重要，因為它們相互影響。
If you have a lot of tonic dopamine, for example, it can make the phasic response smaller.
例如，如果你有大量持續釋放的多巴胺，那么它可以減少時相反應。
Neurons get a signal that there's already a lot of dopamine outside the cell,
神經元得到信號，細胞外已經有大量的多巴胺了，
so they don't have to release as much when they try to send a signal to the next neuron.
所以它們試圖向下一個神經元發送信號說它們不需要釋放那么多的多巴胺。
ADHD seems to do the opposite.
多動癥似乎正好相反。
People with the disorder seem to have a lower level of tonic dopamine,
患有這種障礙的人似乎有較低水平持續釋放的多巴胺，
meaning that the phasic responses are bigger.
這意味著他們的時相反應更大。
You might think that a bigger reward would be a good thing because it would increase your motivation.
你可能會認為一個更大的獎勵是好事，因為它會增加你的動機。
But that's not what happens.
但事實并非如此。
The low arousal theory says that since there's less dopamine sitting between your neurons,
低覺醒理論認為，由于你神經元之間的多巴胺較少，
you need much more stimulation to get it flowing the way it would in someone without ADHD.
你就需要更多的刺激讓它像沒有多動癥的人那樣流動。
That translates to being hypersensitive to your environment.
這意味著你對你的環境極度敏感。
Dropping what you're doing to explore something new you just noticed becomes an almost impossible-to-resist urge.
放棄你正在做的事情從而去探索你剛剛注意到的新事物，成為一種幾乎無法抗拒的沖動。
And maybe you end up bouncing around a bunch to get more of those new and interesting things happening.
也許你最終會跳來跳去，來獲取更多有趣的新事物。
That's where stimulant medications come in.
這就是興奮劑藥物的用武之地。
They get more of that dopamine out between your neurons
它們能讓你的神經元釋放更多的多巴胺，
so you're not constantly looking for stimulants in your environment.
這樣你就不會一直在環境中尋找刺激物了。
Now there are two major categories of stimulants used to treat ADHD:
現在有兩大類興奮劑用于治療多動癥：
there is methylphenidate, which is what's in Ritalin,
有哌醋甲酯，也就是利他林，
and amphetamines, which take a few different forms in medications like Adderall and Vyvanse.
和安非他命，它有幾種不同的藥物形式，比如阿德拉和二甲磺酸賴右苯丙胺。
No matter what category they're in, these stimulants target dopamine.
無論它們屬于哪一類，這些刺激物都針對多巴胺。
Methylphenidate is a dopamine reuptake inhibitor,
哌醋甲酯是多巴胺再攝取抑制劑，
which means that when a neuron sends out some dopamine,
這意味著當神經元釋放多巴胺時，
the drug prevents it from collecting back whatever doesn't get picked up by the next neurons right away.
該藥物阻止它收回沒有被下一個神經元立刻接收的所有物質。
Amphetamines work a little differently:
安非他命的作用有點兒不同：
instead of keeping neurons from collecting the dopamine they've already released,
它不是阻止神經元收集已經釋放的多巴胺，
it stimulates them to release more of it.
而是刺激它們釋放更多。
But both types of stimulants specifically help increase tonic dopamine levels, by leaving more dopamine out between the cells.
這兩種刺激物都能通過在細胞間留下更多多巴胺來增加持續釋放多巴胺的含量。
The idea is that this is closer to what's happening in a typical brain.
該想法是這更接近于典型大腦的情況。
Arousal goes up, and since there's plenty of tonic dopamine to go around, the phasic dopamine response gets smaller.
覺醒增加，因為有大量持續釋放的多巴胺流動，時相反應因而變小。
All of that leads to less of a need to get more stimulation from your environment, which makes it much easier to focus.
所有這些都能減少你從環境中獲得更多刺激的需要，使你更容易集中注意力。
So for a lot of people diagnosed with ADHD, these stimulants can help a lot.
所以對于很多被診斷患有多動癥的人來說，這些興奮劑能起到很大作用。
There are other treatment options, but they're generally less effective.
多動癥還有其他的治療方法，但通常效果不佳。
But their widespread availability leads to a lot of people using them recreationally,
但是多巴胺的廣泛實用性導致很多人用它們來消遣，
whether to help them study or by taking a large dose to get a high.
不管是幫助他們學習，還是大劑量地服用來獲得快感。
That's a bad idea for all kinds of reasons.
出于各種原因，這都不是個好主意。
Both types of stimulants can cause addiction when you take higher doses or use them more often than prescribed,
當你服用高劑量或經常使用這兩種類型的興奮劑時，都可能會上癮，
not to mention side effects like trouble sleeping and heart problems.
更不用說失眠和心臟問題等副作用了。
And if you don't have ADHD, they also … might not really have cognitive benefits.
如果你沒有多動癥，它們可能不會有什么認知上的好處。
Not all studies agree on this, so we'll need more research to know for sure.
并不是所有的研究都同意這一點，所以我們需要更多的研究來確定。
But reviews published in 2011 and 2012 found
但2011年和2012年發表的評論發現，
only a few examples of these stimulants improving mental performance in people without ADHD.
只有少數幾種興奮劑能改善非多動癥患者的大腦功能。
And typically those were rote memory tasks,
而且這些通常都是機械的記憶任務，
and only small improvements, and maybe only for some people who were recorded.
并且改善效果很小，也許只對那些被記錄下來的人有用。
In other cases, someone's performance only changed if they expected the drugs to improve their performance,
在其他情況下，只有當人們期望藥物能改善自己的表現時，他們的表現才會改變，
which suggests that there's a placebo effect involved.
這表明其中有安慰劑效應。
Again, we don't know for sure that these meds don't help people without ADHD,
再說一次，我們也不確定這些藥物對沒有多動癥的人是否有幫助，
so don't use this as a test to diagnose yourself or anything.
所以不要用這個做測試來診斷你自己或者其他什么。
But stimulants work for ADHD because they change the chemistry of your brain
但是興奮劑對多動癥有效，因為它們能改變你大腦中的化學物質
to counteract the differences that cause problems with focus, along with all of those other executive functions.
以消除差異導致的焦點問題，以及所有其他執行功能。
It's not about giving people more energy.
它不光是給人們更多的能量。
And for people without ADHD, taking them might be risking some nasty side effects for the same thing they'd get from a placebo.
對于沒有多動癥的人來說，服用這些藥物可能會產生一些嚴重的副作用，就像服用安慰劑一樣。
Thanks for watching this episode of SciShow Psych!
感謝您收看本期的心理科學秀！
For more about how psychiatric drugs can affect your brain,
要想知道更多精神病藥物如何影響你大腦的內容，
you can check out the episode where we debunked a bunch of misconceptions about antidepressants.
你可以看看我們對抗抑郁藥物的很多誤解的揭露那期。
Thank you for subscribing.
感謝您的訂閱。
And if you're not subscribed, now you feel bad
如果你沒有訂閱，你現在會感覺不好
bacause I thank to you for doing the thing you didn't do, so you have to subscribe.
因為我感謝了你沒有做過的事，所以你必須訂閱。
