In my job as a psychologist, I deal with addiction.
作为一名心理学研究者，我经常要跟吸毒成瘾问题打交道。
I work with people with heroin and crack cocaine dependence.
我的工作面对的是那些对海洛因和可卡因上瘾的人。
But with heroin and crack cocaine...I regularly see people brought to their knees, lives ruined, even deaths.
但使用海洛因或可卡因...我常常看到许多使用者活得很卑贱，苟延残喘，甚至失去生命。
But by comparison, for cannabis, it seems to me the effects are like a walk in the park.
相比之下，大麻对我来说不过是闲庭漫步。
And yet this is the one drug that's rarely out of the public eye, and shrouded in controversy.
它是唯一一种罕见能逃过公众的审视，被争论掩盖的药物。
And that's because more people use cannabis than all other illicit drugs put together.
那是因为，大麻的使用者，比其它所有违禁药品的使用者总和还多。
According to a United Nations report, almost one in 20 adults across the globe uses it each year.
根据美国的一份报告，全球每年有1/20的成年人使用大麻。
Of the people watching this programme, one in three will have tried it, and thousands will be smoking it now.
正在观看本节目的人中，1/3的人曾经试过，上千人甚至正在使用。
I've tried cannabis.
我试过大麻，抽过几次。
I've smoked it a few times. And yes, I've inhaled.
没错，我吸食过。
Did I like it?
我喜不喜欢？
Not really.
其实不。
I was giggly, and having said that, though, I felt a bit uneasy and a bit behind the conversation, a bit thick, to be honest.
说这可能有点可笑，但坦白说，我感到有点不自在，说话词不达意，脑袋有点不清楚。
And it wasn't really for me.
它实在是不适合我。
But I can see the attraction, I can see that feeling out of control,
但我感受到了诱惑，也感受到了失控，
relaxed and enjoying the flow of a conversation would be, for many people, a good thing to do.
放松下来享受自然流畅的对话，对很多人来说是一件好事。
But I want to know why one simple weed has such a profound impact on all our lives.
但我想知道，为什么这种普通野草，会对我们的生活造成如此深远的影响。
The story of the cannabis plant begins 50 million years ago, in an unexpected place.
大麻的故事从5千万年前一个不同寻常的地方开始。
This is Kazakhstan. I'm hoping to find out why this psychoactive plant might have evolved here, of all places.
这里是哈萨克斯坦，世界如此之广，为何大麻偏偏发源于此，我希望找到答案。
Professor Kanat Sarsenbaev is Kazakhstan's national cannabis expert.
Kanat Sarsenbaev教授是该国权威的大麻专家。
He takes me to the nearby mountains to explain.
他带我来到附近的山上进行解释。
So here we are in the Tian Shan mountains.
我们来到了天山，
Is this the origin of cannabis?
这里就是大麻的发源地吗？
I think so, because cannabis evolved in this place many million years ago.
我认为是的，因为大麻在几百万年前就在这里生长。
And after evolving, it distributed through the Tian Shan chain to China.
然后，它沿着天山山脉进入了中国。
After this, to all the world.
之后遍布了世界各地。
The Tian Shan mountain chain stretches 2,500km, reaching into China and Pakistan.
天山山脉全长2500公里，连接着哈萨克斯坦和中国。
While it's hard to know exactly where along this chain cannabis evolved, what it evolved from is clear.
尽管很难知道大麻发源的确切地点，但它的物种来源却很清晰。
Cannabis is a close relative of the hop plant, but with one crucial difference.
它是啤酒花的近亲，但它们有一个重大的区别。
Cannabis contains a chemical called THC, tetra-hydro-cannabinol, the active ingredient, which gets you stoned.
大麻含有一种称为四氢大麻酚THC的化学物质，是一种能产生迷幻效果的活性物质。
