The study found that smoking rates for people with mental illness were generally higher in states where overall smoking rates were high. Utah had the lowest rate of smoking among people with mental illness — 18.1 percent — while West Virginia had the highest rate, at 48.7 percent. Smoking among people with mental illness was higher among the poor and less educated, and among American Indians and Alaska Natives, although every ethnic group had significant percentages of smokers.

The study noted several possible reasons that smoking among the mentally ill has been and remains high, including marketing by the tobacco industry and the historical use of cigarettes as an incentive to improve behavior in psychiatric hospitals.

“There are some effects of nicotine which can mask some of the negative effects of mental illness,” Dr. Frieden said. The study said that smoking can also make some medications less effective, which may then lead the person with mental illness to smoke more to quell symptoms. And it said that people with mental illness, many of whom struggle to live a financially and socially stable life, may be less able to cope with withdrawal symptoms from quitting cigarettes.