美国国家公共电台 NPR--Psychedelic drugs may launch a new era in psychiatric treatment, brain scientists say

Psychedelic drugs may launch a new era in psychiatric treatment, brain scientists say

Transcript¹

One of the hottest tickets at this year's Society for Neuroscience meeting in San Diego was a session on psychedelic drugs.

About 1,000 brain scientists squeezed into an auditorium² at the San Diego Convention Center for the symposium³, called Psychedelics and Neural⁴ Plasticity.

They'd come to hear talks on how drugs like psilocybin and MDMA can alter individual brain cells, can help rewire the brain, and may offer a new way to treat disorders⁵ ranging from depression to chronic⁶ pain.

"I was pleasantly surprised at the number of people," says Alex Kwan, a biomedical engineer at Cornell University who spoke⁷ at the session.

"In the last couple of years there has been a lot of public excitement about psychedelics," Kwan says. "The scientists are catching⁸ on now that we just don't know much about what these compounds do."

So during the session, Kwan and several other researchers shared what they are learning about the drugs.

Rewiring the brain

Kwan described his own work on how psilocybin, the active ingredient in magic mushrooms, seems to help the brain rewire by generating new connections between neurons.

A study of mice found that psilocybin altered dendrites, the branch-like structures that extend from a nerve cell and receive input⁹ from other cells.

Dendrites form connections through small protrusions known as dendritic spines¹⁰. And in mice that got psilocybin, the size and number of these spines increased by about 10%, which allowed cells to form new connections.

"When we give mice a single dose of psilocybin, we can see those new connections form within a day," Kwan says. "And then they can last more than a month," which is the equivalent of many months in a human.

New connections are a critical part of the rewiring process known as brain plasticity, which allows the brain to learn and adapt.

"Psychedelics seem to elevate plasticity," Kwan says.

One-and-done treatment?

Brain plasticity may explain why a single dose of a psychedelic drug can have a long-lasting impact on disorders like anxiety, depression and PTSD.

"It can be months or years," says Dr. Gitte Knudsen a neurologist from University of Copenhagen in Denmark who spoke at the psychedelics session. "It's a stunning¹¹ effect."

These long-term effects have been shown with drugs including psilocybin, LSD and DMT (ayahuasca), Knudsen says. In contrast, most existing psychiatric drugs need to be taken every day.

But psychedelic drugs have some drawbacks. They can cause nausea¹² or produce hallucinations that are frightening or unpleasant.

"It can be a quite overwhelming experience to people," Knudsen says. "And for that reason, you need to prepare them for that, and you also need to be with them while they are in the experience."

Even when patients are well prepared for a session, Knudsen says, they may have mixed feelings afterward¹³.

"When people have been through a psychedelic experience in my lab, they say, 'Wow this was amazing, this was just a fantastic experience,'" she says. "And you ask them, 'Well, would you like to come back next week for another session?' They say, 'Thank you, but no thank you.' "

Psychedelics in the mainstream¹⁴

The fact that psychedelics were featured at the world's largest meeting of brain scientists suggests the drugs are poised¹⁵ to enter the scientific mainstream. That's a recent development.

Psychedelic research was popular in the 1950s but pretty much ended after the mid-1960s when the drugs were made illegal in the U.S. and Europe.

In the 1990s, a few researchers began cautiously studying how drugs like LSD, MDMA and psilocybin might help with psychiatric conditions like depression and PTSD.

And in 2016, a pair of studies published by prominent researchers "really piqued¹⁶ everyone's interest," says Dr. Joshua Gordon, who directs the National Institute of Mental Health.

Both studies found that a single treatment with psilocybin reduced anxiety and depression in cancer patients.

That has led to some large studies of psychedelics, including one published in The New England Journal of Medicine in November showing that psilocybin helped people with major depression who hadn't been helped by other treatments.

Studies like that one suggest that psychedelics "are going to be beneficial and useful" in treating psychiatric disorders, Gordon says.

But the effects found in large studies of psychedelics have been much less dramatic than in some of the earlier, smaller studies, Gordon says. Also, he says, some companies hoping to market psychedelics have overstated their benefits.

"There is a lot of hype," he says, "and a lot of hope."

1 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

2 auditorium   

n.观众席，听众席；会堂，礼堂

参考例句：

• The teacher gathered all the pupils in the auditorium.老师把全体同学集合在礼堂内。
• The stage is thrust forward into the auditorium.舞台向前突出，伸入观众席。

3 symposium   

n.讨论会，专题报告会；专题论文集

参考例句：

• What have you learned from the symposium?你参加了这次科学讨论会有什么体会？
• The specialists and scholars present at the symposium come from all corners of the country.出席研讨会的专家学者们来自全国各地。

4 neural   

adj.神经的，神经系统的

参考例句：

• The neural network can preferably solve the non- linear problem.利用神经网络建模可以较好地解决非线性问题。
• The information transmission in neural system depends on neurotransmitters.信息传递的神经途径有赖于神经递质。

5 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

6 chronic   

adj.(疾病)长期未愈的，慢性的；极坏的

参考例句：

• Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
• Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。

7 spoke   

n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说

参考例句：

• They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
• The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。

8 catching   

adj.易传染的，有魅力的，迷人的，接住

参考例句：

• There are those who think eczema is catching.有人就是认为湿疹会传染。
• Enthusiasm is very catching.热情非常富有感染力。

9 input   

n.输入(物)；投入；vt.把(数据等)输入计算机

参考例句：

• I will forever be grateful for his considerable input.我将永远感激他的大量投入。
• All this information had to be input onto the computer.所有这些信息都必须输入计算机。

10 spines   

n.脊柱( spine的名词复数 )；脊椎；（动植物的）刺；书脊

参考例句：

• Porcupines use their spines to protect themselves. 豪猪用身上的刺毛来自卫。
• The cactus has spines. 仙人掌有刺。 来自《现代英汉综合大词典》

11 stunning   

adj.极好的；使人晕倒的

参考例句：

• His plays are distinguished only by their stunning mediocrity.他的戏剧与众不同之处就是平凡得出奇。
• The finished effect was absolutely stunning.完工后的效果非常美。

12 nausea   

n.作呕，恶心；极端的憎恶(或厌恶)

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕期常有恶心的现象。
• He experienced nausea after eating octopus.吃了章鱼后他感到恶心。

13 afterward   

adv.后来；以后

参考例句：

• Let's go to the theatre first and eat afterward. 让我们先去看戏，然后吃饭。
• Afterward,the boy became a very famous artist.后来，这男孩成为一个很有名的艺术家。

14 mainstream   

n.（思想或行为的）主流；adj.主流的

参考例句：

• Their views lie outside the mainstream of current medical opinion.他们的观点不属于当今医学界观点的主流。
• Polls are still largely reflects the mainstream sentiment.民调还在很大程度上反映了社会主流情绪。

15 poised   

a.摆好姿势不动的

参考例句：

• The hawk poised in mid-air ready to swoop. 老鹰在半空中盘旋，准备俯冲。
• Tina was tense, her hand poised over the telephone. 蒂娜心情紧张，手悬在电话机上。

16 piqued   

v.伤害…的自尊心( pique的过去式和过去分词 )；激起（好奇心）

参考例句：

• Their curiosity piqued, they stopped writing. 他们的好奇心被挑起，停下了手中的笔。 来自辞典例句
• This phenomenon piqued Dr Morris' interest. 这一现象激起了莫里斯医生的兴趣。 来自辞典例句