Taking medications to treat insomnia or anxiety may shorten some people's lives, according to the results of a 12-year study in Canada.
The new findings are based on surveys of more than 14,000 Canadians, ages 18 to 102, that began in 1994 and kept track of their mortality rates.
Every two years, participants answered questions about their social demographics, lifestyle and health. They also answered questions about their use of sedative drugs, including tranquilizers such as Valium, or sleeping pills, such as Nytol.
For respondents who, at the start of the survey, reported taking medication for insomnia or anxiety at least once in the month, the mortality rate over the 12-year period was 15.7 percent. By comparison, respondents who had reported not using such medication had a mortality rate of 10.5 percent.
"These medications aren't candy, and taking them is far from harmless," study researcher Geneviève Belleville, a professor at Université Laval in Québec, said in a statement.
After taking into account other factors that might affect mortality rates including alcohol and tobacco consumption, physical health, physical activity level and symptoms of depression the researchers associated sleeping pills or anxiety-relieving medications with a 36 percent increase in the risk of dying during the 12-year period.
The greatest differences in mortality rate between drug users and nonusers were observed in the age groups of 55 to 64 years and 65 to 74 years, according to the study.
The researchers, whose results appear in the September issue of the Canadian Journal of Psychiatry, said a number of factors might explain the link between these medications and increased mortality. Sleeping pills and anxiety drugs affect reaction time, alertness and coordination, and so they may contribute to falls and other accidents, the researchers said. The medications also may aggravate certain breathing problems during sleep. And some of the drugs work on the central nervous system in ways that may affect judgment and thus increase the risk of suicide.
"Given that cognitive behavioral therapies have shown good results in treating insomnia and anxiety, doctors should systematically discuss such therapies with their patients as an option. Combining a pharmacological approach in the short term with psychological treatment is a promising strategy for reducing anxiety and promoting sleep," Belleville said.