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Can a drug improve your brain power?

10 November 2011 Last updated at 12:08 GMT

Some students are using cognitive enhancing drugs, or "smart" drugs, to help them get through exams.

But scientists say they are putting themselves at risk because they are buying them over the internet and the long term risks are unknown.

They want the government to step in to make sure safety studies are carried out so that more is known about them.

Newsnight's Susan Watts reports.