Updated

Patients in psychiatric hospitals who take part in smoking cessation programs during their stay are more likely to be smoke-free after 18 months, compared to patients who don't participate in the programs, says a new study.

What's more, researchers found that quitting smoking appeared to be safe for the patients and was tied to a decreased risk of being admitted back into the hospital.

"That's a new finding and it needs to be replicated, but we're excited that it didn't cause any harm and may have supported their recovery," said Judith Prochaska, the study's lead author from the Stanford Prevention Research Center in California.

Prochaska and her colleagues write in the American Journal of Public Health that it's estimated people with mental illnesses use two to four times more tobacco than the general population.

The lives of people with serious mental illnesses are about 25 years shorter than the rest of the population, on average, and the main causes of early death are tobacco-related diseases.

Most U.S. hospitals have been smoke-free since 1993, but at least half of hospital psychiatric units allow smoking and sell cigarettes, according to the researchers.

"It used to be that people with mental illnesses had a waiver," Dr. Steven Schroeder, the Distinguished Professor of Health and Health Care at the University of California, San Francisco (UCSF), said.

Schroeder, who was not involved with the new research, said some people believed psychiatric inpatients were not ready or didn't want to quit smoking and that giving up smoking might make their conditions worse.

For the new study, Prochaska and her colleagues recruited smokers between July 2006 and December 2008 from an inpatient psychiatry unit on the UCSF medical school campus.

The psychiatric unit was a smoke-free environment, but the researchers write that few smokers were offered or referred for smoking cessation treatment.

They recruited 224 patients who had smoked at least five cigarettes per day before their hospitalization, were at least 18 years old and spoke fluent English. The most common psychiatric diagnoses were depression and schizophrenia.

The researchers randomly assigned 111 of the participants to receive the usual care provided by the psychiatric unit and 113 to receive smoking cessation treatment.

The smoking cessation treatment consisted of determining where a person was in the process of quitting at the start of the program, completing a computer program and a counseling session, and receiving free nicotine replacement patches for up to six months after hospitalization. Letters were also mailed to patients' primary care doctors requesting their support.

After three months, 3 percent of the usual care group had not smoked a cigarette in seven days. That compared to about 14 percent among those who went through the smoking cessation program.

By 18 months, about 8 percent of the usual care group was smoke-free, compared to 20 percent of patients assigned to the program.

The researchers say people without psychiatric illnesses who participate in smoking cessation programs have a quit rate of about 25 percent.

Prochaska and her colleagues also found that patients who received usual care were almost twice as likely to be hospitalized for psychiatric treatment again as those who went through the program.

"I think this is a really important paper that they did. In a way, it really challenges psychiatric hospitals to address something they've been neglecting for some time," Dr. Nancy Rigotti, a professor of medicine at Harvard Medical School in Boston who has studied tobacco control, said.

"Psychiatric hospitals can adopt something like this and benefit patients in an additional way other than treating the illness that brought them into the hospital," Rigotti, who was not involved with the new study, said.

Prochaska said her team is currently working with a health economist to examine the cost effectiveness of the program, and that it's looking "encouraging."