LOS ANGELES, CA (Catholic Online) - In fact, academics believe the side effects of the drugs are so harmful that doctors should avoid prescribing them. It's estimated that around 1.5 million Britons are taking the pills at any one time and more than 10 million prescriptions are handed out annually.

Researchers also estimate that up to eight percent of the over-65s have used them within the last few years to treat insomnia or anxiety. There is growing evidence that they have serious side effects and a number of studies linking them to falls, memory problems, panic attacks and early death.

Academics from Harvard University in the U.S. and the University of Bordeaux in France discovered that elderly people who had taken the drugs within the last 15 years were 50 percent more likely to get dementia.

Scientists believe that the calming effect they have on subjects may be interfering with chemicals in the brain known as neurotransmitters, which may be causing dementia.

"There is a potential that these drugs are really harmful," Professor Tobias Kurth, who works jointly at Harvard University's School of Public Health and the University of Bordeaux says.

"If it is really true that these drugs are causing dementia, that will be huge. But one single study does not necessarily show everything that is going on, so there is no need to panic.

"These drugs certainly have their benefits and if you prescribe them in a way they should be prescribed they treat very well," Kurth adds.

Published in the British Medical Journal, the study involved 1,063 men and women over the age of 65 for a period of 20 years in southwest France. None of the participants had previously suffered from dementia and no one was taking benzodiazepines.

The researchers followed them up after 15 years and found that 253 had developed dementia. Those who didn't take the drug, 3.2 would be expected to get the condition.

But among 100 patients on these drugs, 4.8 would get dementia, which is a highly significantly higher proportion. The patients had taken the pills at least once at some point in the previous 15 years.

The study concluded: "Considering the extent to which benzodiazepines are prescribed and the number of potential adverse effects, indiscriminate widespread use should be cautioned against."

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