Health benefits of smoking

Some studies have discovered health benefits correlated with smoking. These studies observed a reduction in the occurrence of some diseases, but all such studies stressed that the benefits of smoking did not outweigh the risks.

Several types of "Smoker's Paradoxes", i.e. cases where smoking appears to have specific beneficial effects, have been observed; often the actual mechanism remains undetermined. For instance, recent studies suggest that smokers require less frequent repeated revascularization after percutaneous coronary intervention (PCI). Risk of ulcerative colitis has been frequently shown to be reduced by smokers on a dose-dependent basis; the effect is eliminated if the individual stops smoking. Smoking appears to interfere with development of Kaposi's sarcoma. a possible reduction in breast cancer among women carrying the very high risk BRCA gene, although overall risk is increased preeclampsia,

A plausible mechanism of action in these cases may be the nicotine in tobacco smoke acting as an anti-inflammatory agent and interfering with the disease process.

In mice, studies have shown nicotine can reduce the amount of DOI-induced head twitches (meant to model tics) related to Tourette's Syndrome[citation needed].

A protective effect of current smoking has been found in Parkinson's disease, although the authors stated that it was more likely that the movement disorders which are part of Parkinson's disease prevented people from being able to smoke than that smoking itself was protective, and personality differences may play a role[60]

Evidence on a possible protective effect of smoking on Alzheimer's Disease is mixed, with some studies finding decreased and some increased[61] [62] likelihood of developing the disease. A recent review concluded that the apparent decrease in risk may be simply due to the fact that smokers tend to die before reaching the age at which Alzheimer's normally occurs. "Differential mortality is always likely to be a problem where there is a need to investigate the effects of smoking in a disorder with very low incidence rates before age 75 years, which is the case of Alzheimer's disease", it stated, noting that smokers are only half as likely as non-smokers to survive to the age of 80.

A plausible explanation for these cases may be the effect of nicotine, a cholinergic stimulant, decreasing the levels of acetylcholine in the smoker's brain; Parkinson's disease occurs when the effect of dopamine is less than that of acetylcholine. Opponents counter by noting that consumption of pure nicotine may be as beneficial as smoking without the risk.

Considering the high rates of physical sickness and deaths among persons suffering from schizophrenia, one of smoking's short term benefits is its temporary effect to improve alertness and cognitive functioning in that disease. It has been postulated that the mechanism of this effect is that schizophrenics have a disturbance of nicotinic receptor functioning.