A drug used to stop people falling asleep is showing promise in enhancing brain power.

Scientists at Cambridge University say it could make people better at remembering things and solving problems.

Healthy volunteers given the treatment, modafinil, scored higher on computer games designed to test their mental function than those given a dummy pill.

This will offer tremendous insight into how the mind works

Danielle Turner, University of Cambridge

The drug is used clinically to treat the debilitating sleep disorder, narcolepsy.

Narcolepsy is a brain disorder characterised by sleep attacks and abnormal eye movement which affects up to one in a thousand people.

Suffers fall asleep anywhere, at any time of day, without warning. At other times sufferers remain conscious, but their entire body goes limp and they are unable to move.

Previous work on modafinil has been limited to its effects on sleeping disorders like narcolepsy. Its effects on a wide range of cognitive functions have not been tested until now.

Danielle Turner, from the Department of Psychiatry at the University of Cambridge, says modafinil could revolutionise current understanding of the way we form and retain memories. It seems to have a unique mechanism of action in the brain.

"In the study, the volunteers given modafinil performed significantly better at neuropsychological tests involving short-term memory and showed less impulsive responding and an increased tendency to reflect on the tasks they were given," she said.

"The research suggests that it may at last be possible to help patients with neuropsychiatric disorders, such as Attention Deficit Hyperactivity Disorder (ADHD), who suffer from selective impairments in memory, problem-solving and planning."

'Tremendous insight'

The researchers plan to test whether young adults suffering from ADHD show similar improvements in mental functioning to the 60 young healthy male volunteers.

They will use brain imaging equipment to study patients' brains while they are playing computer games.

"This will offer tremendous insight into how the mind works," said Ms Turner.

"Visualising modafinil acting in the brain could help us find out exactly which brain cells (or neurones) and neurochemicals are involved in our memory and problem solving processes."

Drugs such as amphetamine and methylphenidate have been used in the past in an attempt to improve some aspects of people's performance when they are tired.

But they can cause impairments in other functions and may be addictive.