Parents are giving their children internet-bought "smart drugs" to boost their performance in the exam room, a psychologist has claimed.
Students are now in the exam revision season
Anti-hyperactivity medicines like Ritalin are being used as a "study aid", says Leicester University's director of education Paul Cooper.
The drug is given to hyperactive children to improve concentration.
But Professor Cooper says taking it without medical supervision is unwise and can be dangerous.
He said: "We are moving into a phase now where informed parents can by-pass the medical profession, go online and prescribe the drug themselves.
"I have anecdotal evidence that a number of parents in this country have done this. I know of three parents who have done it in one state secondary school.
"That's just one school and it is likely to be replicated on a massive scale," he added.
Prof Cooper said the parents doing this probably thought their children had mild, but undiagnosed, ADHD and that drugs like Ritalin might buy them much needed extra time in the examination room.
A child with the mildest form of the disorder was likely to find it difficult to concentrate for the length of time it took to write an essay in an exam setting, he said.
People with the condition have a poor attention span and tend to be impulsive and restless, yet the underlying cause is still poorly understood.
Drugs like Ritalin would help 80% of people regardless of whether they had the disorder or not, he said.
But there were health risks to taking any drug in an unsupervised way.
"My big concern is the regulatory aspect and the fact that nobody should be buying this kind of drug over the internet and they should not be taking it without medical supervision," Prof Cooper added.
"Even though Ritalin is considered to be a relatively safe medication it still has to be prescribed properly.
"It could improve performance, but people will respond differently. If a person has a history of seizures for example - they should not be prescribed this drug.
"In our culture, educational attainment is valued so highly. People sell their houses to get near a school or lie about where they live to get a child into a school.
"It's a distorted value in our culture. So anything a parent can do to get some kind of educational advantage - they will do it."
Prof Cooper says he would like to see further research into the scale of the problem.