Nicotine can be good for the brain, research suggests, and its effects could form the basis for new drugs to stave off Alzheimer's disease.

Smokers may already be familiar with the mental “buzz” from nicotine but researchers from King's College London found that in rats it improved their learning, memory and performance on cognitive tasks by up to 15 per cent.

Scientists pointed out, however, that the effect was very small and the health risks of smoking and toxic effects of using nicotine patches would outweigh the benefits in healthy people. Pharmaceutical companies are hoping to amplify the positive effects of nicotine to benefit dementia patients, while minimising the risk of addiction.

Nicotine acts on various receptors in the brain to produce a stimulating and also addictive effect. In research to be presented at the Forum of European Neuroscience in Geneva today, the King's College team found that injecting the rats with nicotine produced improvements in sustained attention and reactions to visual stimuli by 5 per cent.

When the rats were distracted with flashing lights and sounds, the concentration of those who had been given nicotine improved by 15 per cent compared with a control group.

Ian Stolerman, from the Institute of Psychiatry, King's College, said he was surprised to find beneficial cognitive effects but added that they were very small. The differences between doses that produced cognitive and toxic effects were also small and, significantly, there was a high risk of addiction.

He added that nicotine was difficult to administer in significant non-harmful doses by conventional means, such as a patch or inhaler.

Drugs based upon the chemical structure of nicotine are already in phase 2 trials to see whether they can forestall the mental decline of Alzheimer's patients. It is thought that the drugs may allow the patients to remain alert and retain their memory for slightly longer.

Professor Stolerman said that there might be side-effects. “We found several similarities and only small differences between the cognitive mechanisms and those involved in the addictive effects of nicotine. The cognitive ‘boost' that many smokers experience from nicotine probably contributes to the reason people smoke cigarettes, so it may not be possible to totally prevent addiction.

“Nevertheless, the potential for abuse of a medicine based on a pure nicotine-like substance is likely to be very small.”

Studying the mechanisms of nicotine action may speed the discovery of more effective cognitive enhancers than nicotine itself, with longer-lasting effects. “This is a promising stage in the years of research,” Professor Stolerman said.

Explore Health

• Expert Advice

• Health Features

• Mental Health

• Alternative Medicine

• Child Health

• Health Club