Pills are supposed to be for the sick. But some are being used by perfectly healthy people. Are we heading for a future of 'cosmetic pharmacology'?

If you could take a drug to boost your brainpower, would you? This is closer to reality than you might think. New mind-enhancing drugs are already on pharmacy shelves, and many people are finding the promise of sharper thinking through chemistry highly seductive.

Drugs to enhance performance are nothing new. Long-haul lorry drivers and aircraft pilots are known to pop amphetamines to stay alert, and university students down caffeine tablets to ward off drowsiness during all-nighters. But these stimulants work by revving up the entire nervous system and the effect is only temporary.

A new generation of cognitive enhancers can improve mental functions in a lasting way. These drugs result from the drive to develop treatments for Alzheimer's disease, Parkinson's disease and other conditions.

Three brain-boosting medications are on the market, available on prescription. Modafinil (marketed under the name Provigil) is a treatment for narcolepsy and other sleep disorders that is proving popular among healthy people who want to enhance their mental prowess.

Another is methylphenidate, better known as Ritalin, the drug used to treat attention deficit hyperactivity disorder (ADHD). And finally donepezil, prescribed for patients with Alzheimer's.

None of these drugs is approved for use in healthy individuals, but a growing number of people are taking them to gain a mental edge. Modafinil, when given to adults playing games specially designed to test mental skills, has been shown to increase cognitive agility, by increasing alertness and the ability to concentrate on a task.

Students will no doubt find smart drugs tempting. Indeed, it has been found that some parents use the Ritalin prescribed to their children, and some academics take these drugs regularly to enhance their memory and concentration. Some users persuade a doctor to prescribe it; others get it illegally over the internet.

Arguments over smart drugs are raging. If a drug can improve an individual's performance, and they do not experience side effects, some argue, it cannot be such a bad thing. What is the difference between a can of caffeine-containing Red Bull and a hike from modafinil?

But where will it all stop? Ambitious parents may start giving mind-enhancing pills to their children. People go to all sorts of lengths to gain an educational advantage and eventually success might be dependent on access to these mind-improving drugs. No major studies have been conducted on the long-term effects. Some neuroscientists fear that, over time, these memory-enhancing pills may end up causing people to store too much detail, cluttering the brain.

Wipe away the pain

So what about the flip side: a drug to erase bad memories? It may have failed Jim Carrey in 'Eternal Sunshine of the Spotless Mind', but neuroscientists have now discovered an amnesia drug that can dull the pain of traumatic events. The drug, propranolol, was originally used to treat high blood pressure and heart disease. Doctors noticed that patients given the drug suffered fewer signs of stress when recalling a trauma.

Scientists found that the drug can disrupt the way memories are stored. This ability could be invaluable in treating trauma victims to prevent associated stress disorders. The research has also triggered suggestions that licensing these memory-blocking drugs may lead to healthy people using them to erase memories of awkward conversations, embarrassing blunders and any feelings for that devious ex-girlfriend.

It may seem tempting to use a drug to prevent a painful experience becoming an unwanted memory. But how would that affect our development as individuals? Bad experiences help make us what we are. We learn from them. They help us avoid repeating mistakes.

And there are other uses that may make us uncomfortable. The military is interested in modafinil as a drug to maintain combat alertness. A drug such as propanolol could be used to protect soldiers from the horrors of war. That could be considered a good thing - post-traumatic stress disorder is common in soldiers. But the notion of troops unaffected by their experience makes many feel uneasy.