More than a third of people believe it is acceptable to use "brain-boosting" drugs to improve performance in exams or interviews, according to the first national survey of its kind.
The Wellcome Trust Monitor survey has investigated Britain's use of and views about drugs developed for conditions such as attention deficit hyperactivity disorder (ADHD) and dementia, which are used by some to study for longer or to improve concentration.
Based on interviews with 1,396 adults and 460 young people aged 14-18, it found that 35 per cent of the adults and 34 per cent of the young people believed it was acceptable to use the drugs to gain an edge, even if they had not been diagnosed with any medical condition.
A smaller proportion, 34 per cent of the adults and 33 per cent of the young people, disapproved.
"It may be that what the survey is picking up is that there is genuine interest and curiosity about this," said Ilina Singh, professor of science, ethics and society at King's College London.
But the survey also suggested that reports claiming that the drugs were already in widespread use were overhyped: only 2 per cent of adults and 1 per cent of young people reported using these drugs to boost mental performance.
Narcolepsy drug modafinil has become one of the drugs of choice, partly as possession is legal and it is available over the internet. It may offer improvements to working memory and wakefulness, but is not approved for use in children by the US Food and Drug Administration, and the NHS says it would be prescribed for under-18s only with "special care".
Ritalin, normally used to treat ADHD, may improve focus for healthy users but its possession without prescription is illegal in many countries.
Experts said that the substantial acceptance of cognition-enhancing drugs suggested by the survey made it important to have reliable studies on their safety and effectiveness. But carrying out large-scale randomised trials has been hampered by ethical problems in using drugs on healthy subjects.
"If young people are going to take it upon themselves to experiment with these drugs, we need some evidence of their safety but also some evidence of their efficacy," Professor Singh said. She questioned whether it might be more valuable to invest in research on the role of sleep, or even meditation, as a means of focusing attention, rather than drugs.
Hilary Leevers, director of education at the Wellcome Trust medical charity, said: "These drugs have not been tested properly, except on clinical programmes, and they have not been tested for long-term use ... We really don't know what the risks are."
Side-effects of Ritalin, according to NHS guidelines for its approved use for ADHD, can vary from sleep disturbance to hallucinations in rarer cases.