科学家指出为什么有些人会成瘾

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Scientists pinpoint why some people become addicts

LONDON (Reuters) - Scientists have identified the part of the brain that may hold the key to why some cocaine users become addicts while others just take the drug socially, researchers said on Tuesday.

Brain scans of cocaine users while they performed simple computer tasks showed changes in the part of the brain responsible for controlling behavior and making appropriate decisions, they said.

This could explain why some people find it easier to quit than others and may shed light on long-term addiction, said Hugh Garavan, a cognitive neuroscientist at Trinity College Dublin who presented his research to a meeting of the Royal Society in London.

\"Most people who try to quit drugs relapse,\" Garavan said in a telephone interview. \"It might have to do with how intact these brain regions are.\"

Cocaine, initially used in patent medicines, beverages and tonics around the turn of the 20th Century, is a drug that in powdered form can be snorted or dissolved in water and injected. Its derivative crack cocaine is even more powerful.

An estimated 1 to 3 percent of adults in developed countries use the drug, which has been linked to a number of medical, psychological and social problems including crime, violence and the spread of diseases like AIDS and hepatitis, according to the World Health Organisation.

Garavan and colleagues used MRI scans to show that cocaine users had reduced neural activity marked by reduced blood flow to the part of the brain involved in things like problem solving, decision making and controlling behavior. Some people were administered cocaine in the experiments.

\"This research helps us move away from thinking of drug dependence as a moral weakness and allows us to see it as more of a medical condition.\"

It was unclear whether the changes were due to the drug itself or whether some kind of natural mechanism in the brain triggers the change, Garavan said.

But better understanding the brain's response to cocaine could eventually help predict people most at risk of developing an addiction and lead to better treatments, he added.

\"One would hope this research would guide the development of new treatments including the development of pharmacological solutions to addiction,\" Garavan said.

http://www.reuters.com/article/healthNews/idUSL2587009320080226
伦敦（路透社）研究人员周二说到，科学家已经鉴定出大脑中的一个部位，这个部位可能是解释为什么有些可卡因使用者成瘾而其他人则只是为应酬使用这种麻药的关键因素。

他们说，在可卡因使用者完成简单的计算工作时进行脑部扫描，可以发现大脑负责控制行为和做出适当决定的部位发生变化。

Hugh Garavan，都柏林Trinity大学的认知神经科学家，在伦敦皇家学会的一次会议上公开了他的研究，他说这可以解释为什么有些人摆脱成瘾容易一些，可能揭示了长期成瘾的秘密。

“大多数人试图摆脱成瘾还是复发了，” Garavan在一次电话采访中说。“这可能与他大脑内这些部位的完整程度有关。”

可卡因，最初在20世纪交替的时候做为成药，饮料和兴奋剂使用，是一种粉末形式，可以被吸食或溶解在水里和注射的药品。它的衍生物可能作用更强有力。

根据世界健康组织显示，估计在发达国家有1％-3％的成年人使用毒品，这可能关联到许多医疗的，心里的和社会的问题包括犯罪，暴力和像艾滋病和肝炎等疾病的传播。

Garavan和同事使用MRI扫描显示可卡因使用者神经活动减少，特征是大脑中涉及到像解决问题，做决定和控制行为的部位的血流减少。在试验中一些人被给予可卡因。

“这个研究帮助我们移除了认为药物成瘾是道德薄弱的想法，使我们以更接近医疗角度的看待它”

Garavan称，这种变化是药物本身作用还是大脑内某些固有机制的靶点变化仍然不清楚。

他补充道，但是更好的理解大脑对可卡因的应答可以最终帮助预测容易发展成瘾的人并知道更好的治疗。

Garavan说“希望这个研究可以新的治疗手段的发展，包括解决成瘾问题的药理学发展。”

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这个实验提示，改善大脑供血可以增加自控能力，有助于戒毒?