Nicotine is addictive and toxic but also can improve memory, learning and attention, according to researchers who say that nicotine-based drugs could be developed to slow the progress of dementia.

An animal study showed that, under normal conditions, nicotine seemed to improve concentration about 5 percent. When test subjects were distracted, however, the performance boost was even more pronounced.

The BBC reported July 13 that nicotine-based drugs, while not a panacea, could allow dementia patients an extra six months of independent living, according to researchers at King's College London.

"It may be possible for medicinal chemists to devise compounds that provide some of the beneficial effects of nicotine while cutting out the toxic effects," noted researcher Ian Stolerman of the school's Institute of Psychiatry.

Smoking, however, is not the way to gain the cognitive benefits of nicotine, said Clive Ballard of the U.K.'s Alzheimer's Society.

"Although nicotine has therapeutic qualities, when it is absorbed through smoking the health risks outweigh the benefits," he said. "Smoking increases risk of vascular dementia, the second most common form of dementia and is associated with a number of other health risks."