Nicotine in Parkinson's Disease - a Therapeutic Track Gone up in Smoke?

In recent decades, numerous studies have found that smoking or the intake of any form of nicotine, such as smokeless tobacco, exposure to environmental tobacco smoke, or even dietary sources such as peppers, reduces the risk of developing Parkinson's disease. Such observations suggest a potential disease-modifying effect of nicotine in Parkinson's disease. Many experimental studies, some of them supported by grants from the tobacco industry, have lent support for such a hypothesis.