What causes opioid addiction, and why is it so tough to combat? - Mike Davis

翻译人员: Wanting Zhong 校对人员: Rong Han

More than 3,000 years ago, a flower began to appear in remedies

三千多年前， 有一种花开始出现在

古埃及医学文献的药方里。

in Ancient Egyptian medical texts.

Across the Mediterranean, the ancient Minoans

而在地中海的对岸， 古代的米诺斯人

likely found ways to use the same plant for its high.

很可能也在用这种植物取得快感。

Both ancient civilizations were on to something—

这两个古代文明 都发现了同一样东西：

opium, an extract of the poppy in question,

鸦片 —— 这种提炼自罂粟花的物质，

can both induce pleasure and reduce pain.

既能产生快感，也能减轻疼痛。

Though opium has remained in use ever since,

虽然鸦片一直沿用到了现在，

it wasn’t until the 19th century that one of its chemical compounds,

但是直到 19 世纪， 它的一种化合物——吗啡

morphine, was identified and isolated for medical use.

才以医疗为目的 被鉴定和分离出来。

Morphine, codeine, and other substances made directly from the poppy

吗啡、可待因，以及其他 直接从罂粟中提取的物质

are called opiates.

统称天然阿片剂。

In the 20th century, drug companies created a slew of synthetic substances

在 20 世纪， 制药公司研制了一系列

与这些阿片剂相似的合成物质，

similar to these opiates,

including heroin, hydrocodone, oxycodone, and fentanyl.

比如海洛因、氢可酮、 羟考酮和芬太尼。

Whether synthetic or derived from opium,

无论是合成的还是由鸦片衍生的，

these compounds are collectively known as opioids.

这些化合物统称为阿片类药物。

Synthetic or natural, legal or illicit, opioid drugs

不管是合成的还是天然的、 合法的还是非法的，

阿片类药物都是很有效的止痛药， 但同时也极容易让人上瘾。

are very effective painkillers, but they are also highly addictive.

In the 1980s and 90s,

20 世纪 80 和 90 年代，

pharmaceutical companies began to market opioid painkillers aggressively,

制药公司开始 极力营销阿片类止痛药，

actively downplaying their addictive potential

并故意在医学界和公众面前

to both the medical community and the public.

淡化它们的成瘾潜力。

The number of opioid painkillers prescriptions skyrocketed,

阿片类止痛药的处方数量直线上升，

and so did cases of opioid addiction, beginning a crisis that continues today.

阿片类药物成瘾的人数也随之猛增， 形成了一直延续至今的危机。

To understand why opioids are so addictive,

要想了解阿片类药物为什么 那么容易让人上瘾，

it helps to trace how these drugs affect the human body from the first dose,

首先就要追踪这类药物 在各阶段对人体的影响，

包括第一次使用时，反复使用之后， 以及长期用药后又突然停药时会发生什么。

through repeated use, to what happens when long-term use stops.

Each of these drugs has slightly different chemistry,

各种阿片类药物的 化学性质都略有不同，

but all act on the body’s opioid system by binding to opioid receptors in the brain.

但都会与大脑中的阿片类受体结合， 从而作用于人体的“愉悦系统”。

The body’s endorphins temper pain signals by binding to these receptors,

人体内的内啡肽会与这些受体结合， 从而削弱疼痛信号，

and opioid drugs bind much more strongly, for longer.

而阿片类药物与受体的结合 更强，也更持久。

So opioid drugs can manage much more severe pain than endorphins can.

所以，相比内啡肽，阿片类药物 能缓解更加严重的疼痛。

Opioid receptors also influence everything from mood to normal bodily functions.

阿片类受体的影响范围很广， 从情绪到人体日常功能都包括在内。

With these functions, too, opioids’ binding strength and durability

阿片类药物的结合强度和持久性

mean their effects are more pronounced and widespread

意味着它们的作用

比体内的天然信号分子 更明显、更广泛。

than those of the body’s natural signaling molecules.

When a drug binds to opioid receptors, it triggers the release of dopamine,

药物与阿片类受体的结合 会触发多巴胺的分泌。

which is linked to feelings of pleasure and may be responsible

多巴胺与愉悦感有关，

摄取阿片类药物时标志性的愉悦感 可能就是由它引起的。

for the sense of euphoria that characterizes an opioid high.

At the same time, opioids suppress the release of noradrenaline,

与此同时，阿片类药物 会抑制去甲肾上腺素的分泌，

which influences wakefulness, breathing, digestion, and blood pressure.

从而影响清醒度、呼吸、消化和血压。

A therapeutic dose decreases noradrenaline enough to cause side effects

治疗剂量的阿片类药物 会导致去甲肾上腺素水平减少，

like constipation.

从而引发一些副作用，比如便秘。

At higher doses opioids can decrease heart and breathing rates to dangerous levels,

更高剂量的阿片类药物则会让心跳 和呼吸频率下降到危险水平，

causing loss of consciousness and even death.

令人失去意识，甚至死亡。

Over time, the body starts to develop a tolerance for opioids.

随着时间的推移， 人体开始对阿片类药物产生耐药性。

It may decrease its number of opioid receptors,

体内的阿片类受体数量可能会减少，

or the receptors may become less responsive.

或者受体的反应会变弱。

To experience the same release of dopamine and resulting mood effects as before,

要想体验与以往等同的 多巴胺分泌和相应的情绪作用，

people have to take larger and larger doses—

人们就必须服用越来越大的剂量，

a cycle that leads to physical dependence and addiction.

而这一循环会导致身体产生 药物依赖性和成瘾。

As people take more opioids to compensate for tolerance,

随着人们摄取更多阿片类药物 以补偿耐药性的作用，

noradrenaline levels become lower and lower,

去甲肾上腺素的水平就会逐渐降低，

to a point that could impact basic bodily functions.

直到开始影响人体的基本功能。

The body compensates by increasing its number of noradrenaline receptors

为了对抗这种变化，人体会增加 去甲肾上腺素受体的数量，

so it can detect much smaller amounts of noradrenaline.

以便能侦测到更低浓度的 去甲肾上腺素。

This increased sensitivity to noradrenaline

这种对去甲肾上腺素敏感度的增加，

allows the body to continue functioning normally—

让人体得以继续正常运作；

in fact, it becomes dependent on opioids to maintain the new balance.

事实上，人体变得必须依赖阿片类药物 才能维持这种新的平衡。

When someone who is physically dependent on opioids stops taking them abruptly,

当一个对阿片产生生理依赖的人 突然停止服用阿片类药物时，

that balance is disrupted.

这一平衡就会被破坏。

Noradrenaline levels can increase within a day of ceasing opioid use.

去甲肾上腺素水平能在停止服用 阿片类药物的一天之内增加，

But the body takes much longer to get rid of

但是人体需要更长的时间

all the extra noradrenaline receptors it made.

才能除掉体内生成的 额外的去甲肾上腺素受体。

That means there’s a period of time

这意味着，人体会有一段时间

when the body is too sensitive to noradrenaline.

对去甲肾上腺素过于敏感，

This oversensitivity causes withdrawal symptoms,

从而导致戒断症状的产生，

including muscle aches, stomach pains, fever, and vomiting.

比如肌肉酸痛、腹痛、发烧和呕吐。

Though temporary, opioid withdrawal can be incredibly debilitating.

阿片类药物戒断症状虽然短暂， 却能让人极度衰弱。

In serious cases, someone in withdrawal can be violently ill

严重的情况下， 戒断症状患者可能会重病一场，

for days or even weeks.

持续几天，甚至几周。

People who are addicted to opioids aren't necessarily using the drugs

对阿片类药物上瘾的人 服药不再是为了寻求快感，

to get high anymore, but rather to avoid being sick.

而是为了避免生病。

Many risk losing wages or even jobs while in withdrawal,

很多人一旦陷入戒断症状， 可能会面临减薪，甚至丢掉工作，

or may not have anyone to take care of them during withdrawal.

或者在发生戒断症状时没人照顾。

If someone goes back to using opioids later,

如果他们以后 重新开始服用阿片类药物，

they can be at particularly high risk for overdose,

他们用药过量的风险 将会大幅提高，

because what would have been a standard dose while their tolerance was high,

因为他们在高度耐药时 服用的“标准”剂量，

can now be lethal.

现在有可能会致命。

Since 1980, accidental deaths from opioid overdose

自从 1980 年以来， 阿片类药物过量导致的意外死亡案例

have grown exponentially in the United States,

在美国已呈现指数性增长，

and opioid addictions have also exploded around the world.

而世界各地的阿片类药物 成瘾人数也在爆发性增加。

While opioid painkiller prescriptions are becoming more closely regulated,

虽然阿片类止痛药的处方 已经得到了更严密的监管，

cases of overdose and addiction are still increasing,

但是过度用药和成瘾的 案例数量仍在持续攀升，

especially among younger people.

特别是在年轻人中。

Many of the early cases of addiction were middle-aged people

很多早期染上药瘾的人是中年人，

who became addicted to painkillers they had been prescribed,

让他们上瘾的是开给他们的止痛药，

or received from friends and family members with prescriptions.

或是家人朋友给他们的处方药。

Today, young people are often introduced to prescription opioid drugs in those ways

如今，年轻人通常是先通过这些途径 接触到阿片类处方药，

but move on to heroin or illicit synthetic opioids that are cheaper

后来却转而吸食海洛因 和非法的合成类阿片剂，

and easier to come by.

因为它们更便宜，也更容易入手。

Beyond tighter regulation of opioid painkillers,

除了更严格地监管 阿片类止痛药之外，

what can we do to reverse the growing rates of addiction and overdose?

我们还能用什么方法减缓 成瘾和用药过量事件的快速增长呢？

A drug called naloxone is currently our best defense against overdose.

目前，有一种叫做纳洛酮的药物 是防止阿片类药物过量的最佳手段。

Naloxone binds to opioid receptors but doesn’t activate them.

纳洛酮会与阿片类受体结合， 但不会激活受体。

It blocks other opioids from binding to the receptors,

它会阻止其他阿片类药物 与受体结合，

and even knocks them off the receptors to reverse an overdose.

甚至能把它们从受体上撞开， 逆转用药过量的情况。

Opioid addiction is rarely a stand-alone illness;

阿片类药物成瘾 鲜少作为患者的唯一病症，

frequently, people with opioid dependence are also struggling

很多时候， 患有阿片类药物依赖的人

同时也在受某种精神疾病的困扰。

with a mental health condition.

There are both inpatient and outpatient programs that combine

目前，有些住院和门诊疗程综合了

medication, health services, and psychotherapy.

药物、保健服务和心理治疗等疗法，

But many of these programs are very expensive,

但是，这类项目大都费用昂贵，

and the more affordable options can have long waiting lists.

而相对便宜的项目 则呈僧多粥少的局面。

They also often require complete detoxification from opioids

而且在开始这类综合治疗之前，

患者往往必须先进行彻底的 阿片类药物解毒。

before beginning treatment.

Both the withdrawal period and the common months-long stay in a facility

戒断期和往往长达数个月的住院期

can be impossible for people who risk losing jobs and housing in that timeframe.

对可能在这段时间内失去工作 和住所的人来说是难以承受的。

Opioid maintenance programs aim to address some of these obstacles

阿片类维持治疗的目的 就是克服这类障碍，

and eliminate opioid abuse using a combination

并且通过结合药物和行为治疗

of medication and behavior therapy.

来消除阿片类药物滥用的问题。

These programs avoid withdrawal symptoms with drugs

为了避免引发戒断症状，

that bind to opioid receptors but don’t have the psychoactive effects

这类疗程使用的药物 会与阿片受体结合，

但不会像止痛药、海洛因等 那样产生精神作用。

of painkillers, heroin, and other commonly abused opioids.

Methadone and buprenorphine

美沙酮和丁丙诺啡

are the primary opioid maintenance drugs available today,

是目前主流的阿片类维持药物，

but doctors need a special waiver to prescribe them—

但是医生必须申请特别许可 才能开出这类药物，

even though no specific training or certification

尽管开出阿片类止痛药

is required to prescribe opioid painkillers.

不需要接受特定训练或获得认证。

Buprenorphine can be so scarce

丁丙诺啡非常稀缺，

that there’s even a growing black market for it.

甚至出现了日渐增长的地下市场。

There’s still a long way to go with combating opioid addiction,

想要赢得与阿片类药物成瘾的战斗， 我们还有很长的路要走，

but there are great resources for making sense of the treatment options.

不过存在很多优质的资源 能帮助你了解各种治疗方案。

If you or someone you know is struggling with opioid use in the United States,

在美国，如果你自己或你认识的人 对阿片类药物成瘾，

the Department of Health and Human Services

可以拨打美国卫生与公众服务部的 求助热线，

operates a helpline: 800-662-4357

号码是 800-662-4357，

and a database of more than 14,000 substance abuse facilities in the US:

他们还建立了一个数据库，包含美国 1.4 万多间治疗药物滥用的机构，

www.hhs.gov/opioids

网址是 www.hhs.gov/opioids。