True fact: smoking cigarettes actually nueroprotective against developing Alzeihmers, Parkinson's disease and schizophrenia.
http://www.epda.eu.com/en/parkinsons/in-depth/managing-your-parkinsons/neuroprotection/research/other-neuroprotective-factors/
Smoking - whilst we do not endorse or advocate the smoking of cigarettes because of the many health risks associated with it, studies have consistently suggested a link between cigarette smoking and Parkinson’s, leading to theories that smoking - in particular nicotine - may be neuroprotective. In animal studies nicotine has been found to stimulate the release of dopamine in the brain and to preserve neurons and dopamine levels.
One study3 found that former smokers had a 22% lower risk of developing Parkinson's and current smokers had a 73% lower risk compared to those who had never smoked and were thought to have a ‘normal’ risk for developing the condition. In fact, there was found to be a correlation between the risk of developing Parkinson’s and the number of years of smoking, the number of years since stopping smoking and the number of cigarettes smoked per day. Whilst smoking does of course have other risks, it does appear to offer neuroprotective properties.