A study of Alzheimer’s patients showed that those who wore nicotine patches were better able to remember and pay attention than those who didn’t. Another study showed that nicotine boosted cognitive function in older people who didn’t have Alzheimer’s, but were showing signs of age-related mental decline.

Nicotine also seems to protect against Parkinson’s disease, in which the death of cells in a small area of the brain results in tremors, impairing movement and as well as cognitive difficulties.

So what’s going on? How does the dreaded addictive component of cigarettes produce health benefits?

For starters, nicotine by itself isn’t very addictive at all, according to Dr. Paul Newhouse, the director of Vanderbilt University’s Center for Cognitive Medicine. Nicotine seems to require assistance from other substances found in tobacco to get people hooked.