大麻對你的大腦有害嗎？ - 阿尼斯·巴吉：英語精讀講義

In 1970, marijuana was classified as a Schedule 1 drug in the United States, 文化背景

1970年，大麻在美國被列為一級管制藥品，

the strictest designation possible,

這是最嚴格的分類，

meaning it was completely illegal and had no recognized medical uses. 用詞

意味著它完全非法，且不具備公認的醫療用途。

For decades, this view persisted and set back research on the drug's mechanisms and effects. 片語動詞

幾十年來，這種觀點一直存在，阻礙了對該藥物機制和效果的研究。

Today, marijuana's therapeutic benefits are widely acknowledged, 用詞

如今，大麻的治療功效已被廣泛認可，

and some nations have legalized medical use or are moving in that direction. 慣用語

一些國家已將醫療用途合法化，或正朝著這個方向發展。

But a growing recognition for marijuana's medical value doesn't answer the question: 表達脈絡

但人們對大麻醫療價值日益增長的認可，並沒有回答這個問題：

Is recreational marijuana use bad for your brain? 用詞

娛樂性使用大麻會對你的大腦有害嗎？

Marijuana acts on the body's cannabinoid system, 片語搭配

大麻作用於人體的內源性大麻素系統，

which has receptors all over the brain and body.

該系統在整個大腦和身體中都分佈有受體。

Molecules native to the body called endocannabinoids also act on these receptors. 用詞

人體自身產生的被稱為內源性大麻素的分子也會作用於這些受體。

We don't totally understand the cannabinoid system,

我們還沒有完全了解大麻素系統，

but it has one feature that provides a big clue to its function. 表達脈絡

但它的一個特徵為它的功能提供了重要線索。

Most neurotransmitters travel from one neuron to the next

大多數神經傳導物質從一個神經元傳遞到下一個神經元，

through a synapse to propagate a message. 用詞

透過突觸來傳遞訊息。

But endocannabinoids travel in the opposite direction. 片語搭配

但內源性大麻素的傳播方向正好相反。

When a message passes from the one neuron to the next,

當訊息從一個神經元傳遞到下一個神經元時，

the receiving neuron releases endocannabinoids.

接收訊息的神經元會釋放內源性大麻素。

Those endocannabinoids travel backward to influence the sending neuron,

這些內源性大麻素反向傳播以影響發送訊息的神經元，

essentially giving it feedback from the receiving neuron. 文法

本質上是接收神經元向它提供回饋。

This leads scientists to believe that the endocannabinoid system 片語搭配

這讓科學家們相信，內源性大麻素系統

serves primarily to modulate other kinds of signals, 用詞

主要作用是調節其他類型的訊號，

amplifying some and diminishing others. 表達脈絡

放大一些訊號並減弱另一些訊號。

Feedback from endocannabinoids slows down rates of neural signaling.

內源性大麻素的回饋會減慢神經訊號的傳輸速度。

That doesn't necessarily mean it slows down behavior or perception, though. 片語搭配

但這並不一定意味著它會減慢行為或感知的反應。

For example, slowing down a signal that inhibits smell

例如，減緩一種抑制嗅覺的訊號，

could actually make smells more intense. 文法

實際上可能會讓嗅覺更敏銳。

Marijuana contains two main active compounds, 用詞

大麻包含兩種主要的活性化合物：

tetrahydrocannabinol, or THC, 文化背景

四氫大麻酚（THC），

and cannabidiol, or CBD.

和大麻二酚（CBD）。

THC is thought to be primarily responsible for marijuana's psychoactive effects 講解

人們認為THC主要負責大麻的精神活性作用，

on behavior, cognition, and perception.

影響行為、認知和感知。

While CBD is responsible for the non-psychoactive effects, 文法

而CBD則負責非精神活性作用，

like endocannabinoids, THC slows down signaling

就像內源性大麻素一樣，THC會減慢訊號傳輸，

by binding to cannabinoid receptors, 片語搭配

它的方式是與大麻素受體結合，

but it binds to receptors all over this sprawling, diffuse system at once, 用詞

但它會同時與這個龐大、分散系統中的各處受體結合，

whereas endocannabinoids are released in a specific place 文法

而內源性大麻素則是在特定的位置釋放，

in response to a specific stimulus.

以響應特定的刺激。

This widespread activity,

這種廣泛的活動，

coupled with the fact that the cannabinoid system indirectly affects many other systems, 文法

加上大麻素系統會間接影響許多其他系統的事實，

means that each person's particular brain chemistry,

意味著每個人獨特的大腦化學成分、

genetics, and previous life experience

基因以及過往的生活經歷，

largely determine how they experience the drug. 片語搭配

在很大程度上決定了他們對這種藥物的體驗。

That's true much more so with marijuana than with other drugs 文法

與那些透過一條或幾條特定途徑產生作用的其他藥物相比，

that produce their effects through one or a few specific pathways.

大麻在這一點上表現得尤為突出。

So the harmful effects, if any, 語氣意圖

因此，有害影響（如果有的話），

vary considerably from person to person.

會因人而異地有很大差別。

And while we don't know exactly how marijuana produces specific harmful effects, 表達脈絡

雖然我們並不確切知道大麻是如何產生特定有害影響的，

there are clear risk factors that can increase people's likelihood of experiencing them.

但有一些明確的危險因素會增加人們經歷這些影響的可能性。

The clearest risk factor is age. 用詞

最明顯的危險因素是年齡。

In people younger than 25,

在25歲以下的人群中，

cannabinoid receptors are more concentrated in the white matter 文法

大麻素受體更集中在白質中，

than in people over 25.

比例高於25歲以上的人群。

The white matter is involved in communication, 片語搭配

白質參與溝通、

learning, memory, and emotions.

學習、記憶和情緒控制。

Frequent marijuana use can disrupt the development of white matter tracts 片語搭配

頻繁使用大麻會破壞白質束的發育，

and also affect the brain's ability to grow new connections. 片語搭配

還會影響大腦建立新神經連結的能力。

This may damage long-term learning ability and problem solving.

這可能會損害長期的學習能力和解決問題的能力。

For now, it's unclear how severe this damage can be 文法

目前還不清楚這種損害會有多嚴重，

or whether it's reversible.

或者它是否可逆。

And even among young people,

即使在年輕人中，

the risk is higher the younger someone is, 文法

年紀越小風險也越高，

much higher for a 15-year-old than a 22-year-old, for instance.

比如15歲的人風險就比22歲的人高得多。

Marijuana can also cause hallucinations or paranoid delusions,

大麻還可能導致幻覺或偏執性妄想，

known as marijuana-induced psychosis. 用詞

這被稱為大麻誘發的精神病。

These symptoms usually subside when a person stops using marijuana, 用詞

這些症狀通常在人們停止使用大麻後就會消退，

but in rare cases, psychosis doesn't subside,

但在罕見的情況下，精神病並未消退，

instead unmasking a persistent psychotic disorder. 用詞

反而暴露了潛在的持續性精神障礙。

A family history of psychotic disorders, like schizophrenia,

有精神分裂症等精神障礙家族史，

is the clearest, though not the only risk factor for this effect. 語氣意圖

是導致這種影響最明顯（雖然不是唯一）的危險因素。

Marijuana-induced psychosis is also more common among young adults,

大麻誘發的精神病在年輕人中也更常見，

though it's worth noting that psychotic disorders usually surface in this age range anyway. 講解

不過值得注意的是，精神障礙無論如何都通常會在這個年齡層顯現。

What's unclear in these cases 文法

在這些案例中尚不清楚的是，

is whether the psychotic disorder would have appeared without marijuana use,

是如果不吸食大麻，這種精神障礙是否也會出現，

whether marijuana use triggers it early, 用詞

還是吸食大麻導致其提前發作，

is a catalyst for a tipping point that wouldn't have been crossed otherwise, 慣用語

或是它作為催化劑突破了原本不會被跨越的臨界點，

or whether the reaction to marijuana is merely an indication of an underlying disorder. 用詞

又或者對大麻的反應僅僅是潛在疾病的一個跡象。

In all likelihood, marijuana's role varies from person to person. 片語搭配

十之八九，大麻所起的作用因人而異。

At any age, as with many other drugs,

不論年齡多大，就像許多其他藥物一樣，

the brain and body become less sensitive to marijuana after repeated uses, 用詞

多次使用後，大腦和身體對大麻的敏感度會降低，

meaning it takes more to achieve the same effects. 文法

意味著需要更大的劑量才能達到同樣的效果。

Fortunately, unlike many other drugs,

幸運的是，與許多其他藥物不同，

there's no risk of fatal overdose from marijuana, 用詞

吸食大麻沒有致命過量的風險，

and even heavy use doesn't lead to debilitating or life-threatening withdrawal symptoms 用詞

即使大量吸食，在停止使用後，

if use stops.

也不會導致令人衰弱或危及生命的戒斷症狀。

There are more subtle forms of marijuana withdrawal, though, 用詞

不過大麻戒斷也有更不易察覺的形式，

including sleep disturbances,

包括睡眠障礙、

irritability, and depressed mood,

易怒和情緒低落，

which pass within a few weeks of stopping use. 片語搭配

這些症狀在停止使用後的幾週內就會消失。

So, is marijuana bad for your brain?

那麼，大麻對你的大腦有害嗎？

It depends who you are. 表達脈絡

這取決於你是誰。

But while some risk factors are easy to identify, 表達脈絡

雖然有些危險因素很容易識別，

others aren't well understood,

但另一些我們了解得還不夠透徹，

which means there's still some possibility of experiencing negative effects, 文法

這意味著仍然有可能遭受負面影響，

even if you don't have any of the known risk factors. 文法

即使你沒有任何已知的危險因素。

The world's most widely used drug is caffeine.

世界上使用最廣泛的藥物是咖啡因。

Over 100,000 metric tons are consumed every year.

每年消耗量超過10萬噸。

How exactly does it keep us awake?

它究竟是如何讓我們保持清醒的？

Find out with this video.

透過這段影片來一探究竟吧。