Scientists looked at 24 studies into modafinil, a drug which promotes wakefulness and is used to treat narcolepsy, excessive sleepiness and sleep disorders resulting from shift work.
They concluded the drug can improve decision making, problem solving and may even make people think more creatively.
Researchers said the drug is safe when taken on a short-term basis, but acknowledged there is limited data available on the effects of long-term use.
Modafinil is the first ‘smart drug’ to be declared effective, but scientists warn the discovery raises serious ethical questions about how it should be treated by society.
“Modafinil can and does enhance some cognitive functions,” said Dr Ruairidh Battleday of Oxford University.