Yale researchers are looking to address the issue of smoking addiction by focusing on one important population — the mentally ill.

A recent study at the Yale School of Medicine provides the most accurate estimates to date of the proportion of smokers in the general population and in populations with mental illness. The finding may provide the data required to tailor anti-smoking campaigns to work effectively on individuals with psychiatric diagnoses, said Philip Smith, postdoctoral fellow in the School of Public Health and study coauthor.

“If we’re going to effect true change in the rates of smoking in the entire population, we need to address the rates of smoking among those with mental illness,” said Sherry McKee, professor of psychiatry at the Yale School of Medicine and study coauthor.

Hoping to improve estimates both of the proportion of the population that smokes and the likelihood that a smoker is able to quit; the researchers analyzed data from the National Epidemiological Survey on Alcohol and Related Conditions, a database containing information from over 43,000 individuals, including information about smoking habits and mental health. The researchers identified a variety of mental illnesses among the subjects, including various forms of depression, manias, anxiety disorders, phobias and substance abuse. Smith said a notable feature of this study is that it addresses differences in cessation of smoking between specific psychiatric diagnoses.

Results of the study confirmed that individuals with diagnoses of mental illnesses are more likely to smoke, with 15 percent of non-diagnosed individuals smoking in comparison to 33 percent of individuals who had received a psychiatric diagnosis. Additionally, only 18 percent individuals with mental illnesses were able to quit smoking over the three-year period of the study, while 22 percent of non-diagnosed individuals successfully quit.

Furthermore, results showed that there are differences in rates of smoking cessation between individuals diagnosed with specific mental disorders. Mood and anxiety disorders correlated with lower quit rates, and individuals with mental illnesses with long-term effects, rather than short episodes, also found it more difficult to quit. The lowest rate of cessation was for individuals with dysthymia, a milder but longer-lasting form of depression, of which only 10 percent were able to stop smoking. Agoraphobia, social phobia and multiple diagnoses were also associated with low quit rates.

These results accorded with the researchers’ expectations, Smith said.

Laura Spoerri, a support group leader at the Elm City affiliate of the National Alliance for Mental Illness not involved with the study, said she regularly finds that people with mental illnesses are addicted to smoking.

Current efforts to curb smoking among mentally ill individuals have had limited success, wrote study authors. Enforcing anti-smoking rules in psychiatric hospitals has not succeeded in encourage lasting non-smoking behavior, according to a 2005 study carried out at Flinders University in Australia. Smith said the results of the Yale study can be used to inform smoking cessation efforts. He cited new efforts by his team to more effectively target tobacco control policies, such as smoking bans and tobacco taxes, toward individuals with mental illnesses.

The results of the study address a very important segment of our population, said Carolyn Mazure, professor of psychiatry and psychology at the Yale School of Medicine. Smith agreed, and said psychiatrists are usually reluctant to address cigarette smoking among those with mental illness.

Not all parties agree on the significance of this study, as the results are not a new addition to common knowledge about mental illness and smoking, Spoerri said.

“The scientific proof is nice, but we’ve known about this for years,” Spoerri said. “The anecdotal proof is so strong and we’ve already been discussing it in groups.”

According to the Centers for Disease Control and Prevention, 18.1 percent adults smoke cigarettes in the United States.