This seems like a weird topic for an op-ed, but the factoids are interesting:
The facts about smoking and mental illness are stark. Almost half of all cigarettes sold in the United States (44 percent) are consumed by people with mental illness. This is because so many people who have mental illnesses smoke (50 to 80 percent, compared with less than 20 percent of the general population) and because they smoke so many cigarettes a day -- often three packs. Furthermore, smokers with mental illness are much more likely to smoke their cigarettes right down to the filters.
I'd like to see this demographic analysis drill down deeper. I imagine the mentally ill population differs from the general population in various ways that may correlate with an increased propensity to smoke.
Photo by Flickr user paszczak000 used under a Creative Commonse license