People who smoke get Parkinson’s Disease FAR LESS than people who don’t smoke. And when people who smoke STOP smoking after many years, which means they’re now middle-aged or older, they very often get diagnosed with Parkinson’s Disease shortly thereafter. Parkinson’s Disease is most common in those of middle-age or older, and middle-age is often when the long-term effects of smoking start to come home to roost, so people often do quit smoking in middle-age — which leaves them smack in the bullseye for Parkinson’s.
Nicotine has an organizing effect on neurotransmitters, and commercial cigarette tobacco has been purposefully engineered to give you all the effects of nicotine in a VERY short time (like, 10 seconds after every puff); there are other psychoactive chemicals in tobacco such as MAOIs, and those exert a wondrous effect on neurotransmitters too. MAOIs were the drugs of choice to treat depression, before the SSRIs came along.
Smoking also apparently plays a big role in maintaining a fast metabolism, which helps prevent weight gain. When people quit smoking, it’s not JUST the fact that they feel compelled to keep sticking stuff in their mouths that makes them gain weight; it’s because their metabolic rate slows down.
The really good news is that if one simply switches to vaping instead of smoking, one can continue getting all the benefits of smoking, without the risks. Although if one needs the MAOIs, then one needs to add WTA, Whole Tobacco Alkaloids, to their ejuice, or simply buy ejuice which contains WTA.