American studies have measured such drug use
Students could one day face dope tests to prove they have not boosted their academic performance with so called "smart drugs", a psychologist suggests.
More students are turning to drugs in an attempt to boost their grades, writes Vince Cakic of Sydney University in the Journal of Medical Ethics.
Among drugs apparently being used are those designed to treat hyperactivity and dementia.
Some academics think their use can be a positive thing, if regulated.
There are calls for a debate.
They say that although much written about the extent of drug use in the UK is anecdotal, studies at American universities suggest as many as one in four students on some campuses are taking stimulants.
Mr Cakic said: "The possibility of purchasing 'smartness in a bottle' is likely to have broad appeal to students seeking to gain an advantage in an increasingly competitive world."
The drugs would be near impossible to ban, he said.
"As laughable as it may seem, it is possible that scenarios such as this [urine testing] could very well come to fruition in the future.
"However, given that the benefits of [smart drugs] could also be derived from periods of study at any time leading up to examinations, this would also require drug testing during non-exam periods," he writes.
"If the current situation in competitive sport is anything to go by, any attempt to prohibit the use ... will probably be difficult or inordinately expensive to police effectively," he warns.
Experts working in the UK are divided on the issue between those who believe such drugs, if taken under supervision, are a legitimate way of boosting performance and those who warn of the health and social dangers of such use.
John Harris, Professor of Bioethics at Manchester University, said: "My position on enhancement generally and on 'smart drugs' in particular is that enhancement is definitely a good thing.
"If they do improve function in a way that is safe enough I think people should make their own choices about whether to access them.
"Drugs are banned by most sports governing bodies, so if athletes use them it is only cheating because it is against the rules.
"In education, there are lots of ways students can steal an advantage over others: they could be privately educated, have extra tuition, have access to expensive study aids or expensive computers.
"All of these, if others do not have access to them, are in a sense unfair but there are good reasons for students to improve their study skills."
Professor Harris believes the sector should be regulated but that use of the so-called "smart drugs" should not be banned.
"There is a lot of evidence that there is a wide black market in these drugs.
"They are available on prescription and on the internet. it would be better if they were regulated so people could have access to these drugs, with their GPs keeping track of them."
Universities as a whole warn students of the health risks with taking drugs not prescribed for them.
A spokeswoman for Universities UK said: "Currently, much of the evidence available on the use of [smart] drugs among students is largely anecdotal.
"However, universities take the issue of drug abuse very seriously, and would have grave concerns about students taking drugs not prescribed to them. Not only is this illegal but it also poses health risks to those students.
"All universities would advise students under pressure to seek advice from university counselling services, welfare officers or their GP."
Dr Ken Checinski, a specialist in addictive behaviour and psychological medicine at St George's, University of London, has treated many young people who have taken such drugs to boost their exam performance.
One was 15.
He says such drugs are marketed as making people cleverer and braver - but says the reality can be the opposite.
"I obviously see the extreme cases," he said, "but people can develop severe anxiety from amphetamines, they make the heart beat fast and can fuel panic attacks, so people feel like they are having a heart attack which is very frightening.
"They can suffer sleeplessness and this can be very long-lasting; and they might have mood disorder not quite as bad as the crash from coming off cocaine but a near crash. They might feel suicidal."
In the most extreme cases, Dr Checinski said people could develop psychosis and have delusions or hear voices.
Dr Paul Howard-Jones, senior lecturer at Bristol University's graduate school of education, says it is vital that the issues are debated now, before such drug use becomes more common.
"We need to have a debate on this now. These drugs will multiply in number, range and power," he said.
"We have a number of well-respected scientists speaking in very positive terms about these drugs in terms of benefits for us as a society and as individuals, but among teachers, there are concerns.
"I can see there are potential huge benefits but they challenge many of the values we have in education and society."
Dr Howard-Jones said possible concerns were about the devaluing of normal achievement and effort, inequalities - because not everyone might be able to afford the drugs - and the possibility of students feeling pressured to use them.
Teachers he had surveyed mostly thought these drugs would increase the education poverty gap, would demand drug testing if they became prevalent, and would not value grades achieved using them as highly as those achieved without drugs.
The calls for debate and continued research are also reflected in the article by Vince Cakic, from Sydney University.
"Perhaps the most that can be hoped for is to have a better understanding of the dangers of (the drugs) so that students will take this into consideration when deciding whether or not to use them," he said.