電影《美麗心靈的永恒陽光》講述的是一對經常爭吵的情侶把痛苦記憶“刪除”的故事。如今，這種電影情節可望成真。

據英國《每日郵報》報道，科學家們已發明出一種可幫助遺忘痛苦的藥片，服用者能忘記過去自己遭受創傷的經歷。不過，有專家警告說，服用它也可能導致人們忘了自己的身份，還可能導致人們無法從錯誤中汲取教訓。

Gordon Brown revisits the moment he described a voter as a 'bigoted woman' - but a new pill could help to numb that painful memory.(Agencies)

The pill that can wipe out those painful memories

Forgetting an unhappy love affair or a traumatic accident could soon be as easy as popping a pill.

At the risk of being accused of developing a pill for everything, scientists have discovered a drug that helps numb the pain of bad memories by flooding the mind with feelings of security and safety.

And the technique could one day be used to cure phobia sufferers of their fears, help soldiers recover from the horrors of battle or allow accident victims to put their trauma behind them.

To test the effectiveness of the drug, researchers created bad memories by giving mice electric shocks while a loud noise was played.

Over time, the creatures learned to associate the sound with the shock, and hearing the noise alone was enough to make them freeze.

But when they were given a drug called brain-derived neurotrophic factor, or BDNF, they lost their fear, the journal Science reports.

The effect of the drug was similar to a psychological technique called extinction training, in which phobia sufferers are repeatedly exposed to their nemesis in a bid to desensitise them to it.

The US government-funded researchers believe that, as in extinction training, the drug did not erase the bad memory completely, but created a sense of safety and positivity that made it easier to cope with.

They think it does this by triggering the growth of connections between cells in a part of the brain that is crucial in dealing with phobias.

BDNF is naturally produced in the brain, and experiments showed that rats with a shortage of the compound struggled to overwrite bad memories.

Failure to overwrite fear is thought to contribute to post-traumatic stress disorder, as well as other psychological problems.

Prozac also raises levels of BDNF, but the researchers believe that more effective drugs could be developed to tackle fears and phobias.

Dr Thomas Insel of the National Institute of Mental Health, which financed the research, said: "Many lines of evidence implicate BDNF in mental disorders."

"This work supports the idea that medications could be developed to augment the effects of BDNF, providing opportunities for pharmaceutical treatment of post-traumatic stress disorder and other anxiety disorders."

A drug that boosts levels of BDNF in the brain might also help people tackle addictions.

The researchers, from the University of Puerto Rico, will now look into the possibility of creating such a pill - and will also study whether exercise could be beneficial in dealing with fear.

The ability to erase painful memories has been the stuff of science fiction and Hollywood blockbusters for decades.

In the film Eternal Sunshine Of The Spotless Mind, a couple, played by Kate Winslet and Jim Carrey, undergo a procedure known as "targeted memory erasure" to wipe out all recollection of each other after their relationship turns sour.

Last year, Dutch researchers discovered that beta-blocker drugs used to treat heart disease may also help patients to banish bad memories.

And scientists have shown that maintaining a stiff upper lip in times of crisis can stop bad memories from being laid down.

Those who refuse to panic during moments of trauma remember less about what they saw than people who are more emotional.

It is thought that by concentrating so hard on keeping their emotions in check, they overload their brain, stopping it from taking in what is happening.

But the field is not without its critics, with some claiming that holding on to and reviewing bad memories is essential if we are to learn from our mistakes.

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（Source: dailymail.co.uk，編輯：Julie）