(单词翻译:单击)
Odds are, you've heard of Ritalin or Adderall.
你可能听说过利他林或阿得拉。
They're both members of the class of drugs called stimulants,
它们都是兴奋剂类的药物，
and they're often prescribed to treat attention deficit hyperactivity disorder, better known as ADHD.
它们经常被用于治疗注意力缺陷多动症（ADHD）。
But stimulants and hyperactivity seem like a weird match.
但兴奋剂和多动症似乎是一对奇怪的组合。
If someone can't sit still, why would you give them more energy?
如果有人坐不住，为什么还要给他们更多的能量呢？
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疗一样，它的答案与大脑中的化学失衡有关。
The way stimulants affect that imbalance can reveal a lot about
兴奋剂影响失衡的方式可以揭示很多内容：
what's really happening when you get distracted or hyperactive,
你在分心或极度活跃时，大脑会发生什么，
and what changes when you are focused and attentive.
你在专注专心某事时大脑又有什么变化。
It can also explain why, if people without ADHD take these meds,
它也能解释没有多动症的人采用这些方法
they might not be getting the boost they think they are.
为什么没有获得他们以为的那种提升。
ADHD doesn't look exactly the same in everybody, but most of the symptoms fall under one main category:
每个人的多动症表现并不完全一样，但大多数症状都属于一个主要类别：
executive functions, which are essentially the mental processes that help you get things done.
执行功能，它基本上是帮助你完成任务的心理过程。
These include the qualities that usually come to mind when people think of ADHD,
这些症状包括人们在思考多动症时通常会想到的品质，
like focusing or remembering details.
比如专注或记忆细节。
But the symptoms can include problems with other things, too,
但是这些症状还包括其他方面的问题，
like organization, time management, and controlling your impulses and emotions.
比如组织、时间管理、控制冲动和情绪。
We haven't completely nailed down what's happening in the brains of people with ADHD,
我们还没有完全确定多动症患者的大脑情况，
because looking directly into people's brains, turns out it's pretty hard.
因为直接观察人们的大脑很困难。
But one of the main ideas is the low arousal theory,
但有一个叫低觉醒理论的主要观点
which basically says that people with ADHD have chronically underaroused brains,
基本讲的是多动症患者的大脑长期处于低兴奋状态，
and that stimulants help by increasing their arousal.
而兴奋剂可以通过加快它的觉醒来帮助它。
To be clear, arousal in this context just means there less brain activity in certain regions.
需要说明的是，这种情况下的觉醒仅仅意味着某些区域的大脑活动减少。
When someone's brain is underaroused, it can mean their neurons aren't firing as much in certain regions,
当一个人的大脑未被充分唤醒时，可能意味着大脑某些区域的神经元没有那么活跃，
or that some neurotransmitters, the chemicals that communicate signals between neurons, aren't flowing properly.
或者是一些神经递质——神经元之间传递信号的化学物质——没有正常流动。
According to the low arousal theory,
根据低觉醒理论的说法，
this leads you to look for new stimulation in your environment to jumpstart your neural activity.
这会让你在自己的环境中寻找新刺激来快速启动你的神经活动。
And from the outside, that looks like you're hyperactive or just inattentive.
外在表现为看起来过度活跃或漫不经心。
More specifically, the disorder has to do with where you find dopamine,
更具体地说，这种障碍与你找到的多巴胺位置有关，
a neurotransmitter related to the brain's pleasure and reward responses.
多巴胺是一种与大脑的愉悦和奖赏反应有关的神经递质。
Generally, more dopamine translates to a greater feeling of reward.
一般来说，多巴胺越多，奖励的感觉就越强烈。
When your dopamine levels are high, you just feel … good.
当你的多巴胺水平很高时，你会感觉…很棒。
One way to measure this is called the tonic dopamine level,
衡量它的一种方法叫做持续释放多巴胺的水平
which is how much dopamine is kind of hanging out between your neurons already.
也就是你的神经元之间游离着多少多巴胺。
But there's also phasic dopamine, which is what your neurons release based on a stimulus
但还有一种阶段性多巴胺，它是你的神经元根据刺激物释放的，
anything from finishing your PhD thesis to noticing the pretty bird outside your window.
这种刺激从完成你的博士论文到注意窗外美丽的小鸟。
Both kinds of dopamine levels are important because they affect each other.
这两种多巴胺水平都很重要，因为它们相互影响。
If you have a lot of tonic dopamine, for example, it can make the phasic response smaller.
例如，如果你有大量持续释放的多巴胺，那么它可以减少时相反应。
Neurons get a signal that there's already a lot of dopamine outside the cell,
神经元得到信号，细胞外已经有大量的多巴胺了，
so they don't have to release as much when they try to send a signal to the next neuron.
所以它们试图向下一个神经元发送信号说它们不需要释放那么多的多巴胺。
ADHD seems to do the opposite.
多动症似乎正好相反。
People with the disorder seem to have a lower level of tonic dopamine,
患有这种障碍的人似乎有较低水平持续释放的多巴胺，
meaning that the phasic responses are bigger.
这意味着他们的时相反应更大。
You might think that a bigger reward would be a good thing because it would increase your motivation.
你可能会认为一个更大的奖励是好事，因为它会增加你的动机。
But that's not what happens.
但事实并非如此。
The low arousal theory says that since there's less dopamine sitting between your neurons,
低觉醒理论认为，由于你神经元之间的多巴胺较少，
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让它像没有多动症的人那样流动。
That translates to being hypersensitive to your environment.
这意味着你对你的环境极度敏感。
Dropping what you're doing to explore something new you just noticed becomes an almost impossible-to-resist urge.
放弃你正在做的事情从而去探索你刚刚注意到的新事物，成为一种几乎无法抗拒的冲动。
And maybe you end up bouncing around a bunch to get more of those new and interesting things happening.
也许你最终会跳来跳去，来获取更多有趣的新事物。
That's where stimulant medications come in.
这就是兴奋剂药物的用武之地。
They get more of that dopamine out between your neurons
它们能让你的神经元释放更多的多巴胺，
so you're not constantly looking for stimulants in your environment.
这样你就不会一直在环境中寻找刺激物了。
Now there are two major categories of stimulants used to treat ADHD:
现在有两大类兴奋剂用于治疗多动症：
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，它有几种不同的药物形式，比如阿德拉和二甲磺酸赖右苯丙胺。
No matter what category they're in, these stimulants target dopamine.
无论它们属于哪一类，这些刺激物都针对多巴胺。
Methylphenidate is a dopamine reuptake inhibitor,
哌醋甲酯是多巴胺再摄取抑制剂，
which means that when a neuron sends out some dopamine,
这意味着当神经元释放多巴胺时，
the drug prevents it from collecting back whatever doesn't get picked up by the next neurons right away.
该药物阻止它收回没有被下一个神经元立刻接收的所有物质。
Amphetamines work a little differently:
安非他命的作用有点儿不同：
instead of keeping neurons from collecting the dopamine they've already released,
它不是阻止神经元收集已经释放的多巴胺，
it stimulates them to release more of it.
而是刺激它们释放更多。
But both types of stimulants specifically help increase tonic dopamine levels, by leaving more dopamine out between the cells.
这两种刺激物都能通过在细胞间留下更多多巴胺来增加持续释放多巴胺的含量。
The idea is that this is closer to what's happening in a typical brain.
该想法是这更接近于典型大脑的情况。
Arousal goes up, and since there's plenty of tonic dopamine to go around, the phasic dopamine response gets smaller.
觉醒增加，因为有大量持续释放的多巴胺流动，时相反应因而变小。
All of that leads to less of a need to get more stimulation from your environment, which makes it much easier to focus.
所有这些都能减少你从环境中获得更多刺激的需要，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.
所以对于很多被诊断患有多动症的人来说，这些兴奋剂能起到很大作用。
There are other treatment options, but they're generally less effective.
多动症还有其他的治疗方法，但通常效果不佳。
But their widespread availability leads to a lot of people using them recreationally,
但是多巴胺的广泛实用性导致很多人用它们来消遣，
whether to help them study or by taking a large dose to get a high.
不管是帮助他们学习，还是大剂量地服用来获得快感。
That's a bad idea for all kinds of reasons.
出于各种原因，这都不是个好主意。
Both types of stimulants can cause addiction when you take higher doses or use them more often than prescribed,
当你服用高剂量或经常使用这两种类型的兴奋剂时，都可能会上瘾，
not to mention side effects like trouble sleeping and heart problems.
更不用说失眠和心脏问题等副作用了。
And if you don't have ADHD, they also … might not really have cognitive benefits.
如果你没有多动症，它们可能不会有什么认知上的好处。
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这一点，所以我们需要更多的研究来确定。
But reviews published in 2011 and 2012 found
但2011年和2012年发表的评论发现，
only a few examples of these stimulants improving mental performance in people without ADHD.
只有少数几种兴奋剂能改善非多动症患者的大脑功能。
And typically those were rote memory tasks,
而且这些通常都是机械的记忆任务，
and only small improvements, and maybe only for some people who were recorded.
并且改善效果很小，也许只对那些被记录下来的人有用。
In other cases, someone's performance only changed if they expected the drugs to improve their performance,
在其他情况下，只有当人们期望药物能改善自己的表现时，他们的表现才会改变，
which suggests that there's a placebo effect involved.
这表明其中有安慰剂效应。
Again, we don't know for sure that these meds don't help people without ADHD,
再说一次，我们也不确定这些药物对没有多动症的人是否有帮助，
so don't use this as a test to diagnose yourself or anything.
所以不要用这个做测试来诊断你自己或者其他什么。
But stimulants work for ADHD because they change the chemistry of your brain
但是兴奋剂对多动症有效，因为它们能改变你大脑中的化学物质
to counteract the differences that cause problems with focus, along with all of those other executive functions.
以消除差异导致的焦点问题，以及所有其他执行功能。
It's not about giving people more energy.
它不光是给人们更多的能量。
And for people without ADHD, taking them might be risking some nasty side effects for the same thing they'd get from a placebo.
对于没有多动症的人来说，服用这些药物可能会产生一些严重的副作用，就像服用安慰剂一样。
Thanks for watching this episode of SciShow Psych!
感谢您收看本期的心理科学秀！
For more about how psychiatric drugs can affect your brain,
要想知道更多精神病药物如何影响你大脑的内容，
you can check out the episode where we debunked a bunch of misconceptions about antidepressants.
你可以看看我们对抗抑郁药物的很多误解的揭露那期。
Thank you for subscribing.
感谢您的订阅。
And if you're not subscribed, now you feel bad
如果你没有订阅，你现在会感觉不好
bacause I thank to you for doing the thing you didn't do, so you have to subscribe.
因为我感谢了你没有做过的事，所以你必须订阅。
