The researchers discovered the link after tracking the health records of 34,727 people for seven-and-a-half years after they were first prescribed such drugs.
When compared to more than 69,418 control patients who did not take such prescription pills, those who took anti-anxiety drugs like Valium and Xanax, or sleep aids like Ambien, Sonata and Lunesta, were twice as likely to die.
The study was published earlier this month in the journal BMJ.
"The key message here is that we really do have to use these drugs more carefully," said Professor Scott Weich, a professor of psychiatry at Warwick. "This builds on a growing body of evidence suggesting that their side effects are significant and dangerous. We have to do everything possible to minimise over reliance on anxiolytics and sleeping pills."
A study published in 2010 in the Canadian Journal of Psychiatry found anti-anxiety med users had a 36 percent higher risk of mortality.
[University of Warwick]