BBC纪录片《大麻 罪恶之种》 第12期：大麻的耐药性效果
Actually, that's quite shocking that you found a connection between cannabis and heroin.
事实上，发现大麻和海洛因存在联系，让我感到非常的震惊。
The history of cannabis exposure produces a tolerance-like effect where they're less sensitive to the drug and that carries over to heroin.
长期使用大麻会产生一种类似耐药性的效果，老鼠再接触药物时，它们的敏感度会降低。接触海洛因时亦如此。
So they need a bigger dose to get the same effect.
因此，为了获得从前那样的快感，它们需要更多的剂量。
Tolerance just refers to the amount of a drug required to get you high when used repeatedly.
耐药性意味着你需要更多剂量的药物，才能达到相同的效果。
It is not the same as addiction or desire for a drug, which is better measured by the effort made to get it.
它与上瘾不同，上瘾可以用对毒品的渴望程度衡量。
But if you then go on and in both groups and increase the number of times they have to nose-poke to get the heroin,
但如果你继续试验，同时增加两组老鼠顶鼻子的次数，
in other words increase the price for getting heroin, then the two groups are the same.
也就是提高它们获得海洛因的难度，你会发现两组的结果是一样的。
Steve gradually increases the number of nose-pokes required for one dose of heroin.
史蒂夫逐渐提高老鼠顶鼻子的次数。
As the workload rises, they reach a point, around 75 nose-pokes where both groups give up and stop working for the heroin.
老鼠顶的次数越来越多，最终到大约75次左右，两组老鼠就都不再顶了，停止获取海洛因。
So with increased effort, the effect between the two groups disappeared.
所以提高次数之后，这两组老鼠获取海洛因的代价是相同的。
Dr. Steve Goldberg: That's true.
是这样的。
This shows there's no difference in the drive to get heroin between rats who have had cannabis and rats who have not.
这显示了使用大麻的老鼠，和未使用的老鼠对海洛因的需求欲望是一样的。
So what's the human implication?
这对人类来说意味着什么？
The human implication basically says that you don't have enduring biological changes that occur because of the cannabis exposure,
这意味着，基本上，吸大麻不意味会上瘾，
that predetermine that you're going to go on and become addicted to other hard drugs.
也不会促使你寻找更烈性的毒品，这种持续的生物学变化不会发生。
It says it's more of a social and historical thing that drives it.
吸毒成瘾，更可能是由于社会或历史的原因。
As ever, the picture is more complicated than a chemical switch in the brain.
现实情况从来比大脑中化学物质转换更加复杂。
It seems it's more likely to be your peer group or life-stresses such as unemployment or the end of a relationship,
看起来，像失业或离婚这样的生活压力或同辈压力，
that lead people from cannabis on to harder drugs.
更可能让人们从大麻转向更强烈的毒品。
Yet there's another accusation levelled at cannabis.
然而，人们对大麻还有另一种看法。
That it triggers one of the most severe of all mental disorders.
就是大麻会导致所有精神疾病中最严重的一种病。
Permanent psychosis, or schizophrenia.
即永久性精神病，也就是精神分裂症。
This is our family.
这是我的家庭。
This is Mark who's 28.
这是马克，他28岁。
Natalie who's 25.
娜蒂莉25岁。
This is Paul who's 19, and this is his twin, Melissa.
这是保罗，19岁。这是他妹妹梅丽莎。他们俩是龙凤胎。
And, as far as we know, none of them suffer from any mental illness of any kind.
据我们所知，他们都不患有任何类型的精神病。
So we think that, it's most probably the cannabis which has caused the difficulties with Paul.
所以我们认为，保罗的问题很大程度是大麻导致的。
