When Amir Rezvani, a professor of psychiatry at Duke University School of Medicine, administered tiny amounts of nicotine to lab rats with impaired attention, it brought their functioning back to normal or near-normal. The rats had been taught to press a lever and receive a reward when they saw a light flash for just a fraction of second. So they had to be quite attentive to get their food. Then Rezvani's researchers impaired their ability to pay attention with drugs, and brought it back with nicotine.
In fact, nicotine improves the attention of normal non-smokers who don't have attention disorders. When researchers administered just seven milligrams to them via nicotine patches, they performed better on a computerized interval timing test. Again, this makes sense--think of soldiers in foxholes trying to keep their focus under grueling and dangerous conditions.
When a similar test was tried with Alzheimer's patients, their ability to learn improved.
The drawback, of course, is that nicotine may be the most highly addictive substance on earth--more addictive than crack cocaine or heroin, and a more difficult addiction to shake, Rezvani said.
Why is that? First, it binds with the receptors in the brain for acetylcholine, one of our most important neurotransmitters and the first ever discovered. Second, because nicotine is usually inhaled, via cigarettes and now e-cigarettes, it hits the brain almost immediately.
"One reason for it being so addictive is that as soon as you smoke, you see the reward," Rezvani said. The same is true of crack cocaine, he said.
All of which leads Rezvani to disagree with the theory that e-cigarettes will help wean people off tobacco, the number one preventable cause of death in the U.S. He believes it's better not to try anything that poses the risk of nicotine addiction. There is, however, widespread disagreement among experts on this subject.
The future of using nicotine to treat attention, memory and cognitive problems may lie in developing a compound that has its benefits without its addictive properties. Researchers at Duke and Georgetown universities are experimenting with one, sazetidine-A.