Sleepwalking to dementia

Common sleeping tablets and anxiety drugs taken by millions of patients have been linked to a 50% increased risk of Alzheimer's disease, researchers said.

Taking the drugs known as benzodiazepines, which include diazepam and lorazepam, for three months or more was linked with a greater chance of being diagnosed with Alzheimer's five years later.

At least 6million prescriptions were issued for the drugs in England last year, and the researchers said the findings are important because of the large numbers of older people taking the medicines.

Researchers described the findings as being of "major importance for public health".

They warned that although it cannot be definitively proven that the drugs are causing Alzheimer's, there is a strong ''suspicion of possible direct causation".

The drugs should be not be taken for more than three months in light of these findings, they said.

Other experts pointed out that the results may reflect that people in the early stages of Alzheimer's are often treated for sleep problems and anxiety, although it is acknowledged this study controlled for this to an extent.

In a research paper published in the British Medical Journal, scientists from the universities of Bordeaux and Montreal said their findings were important "considering the prevalence and chronicity of benzodiazepine use in elderly populations and the high and increasing incidence of dementia".

They said: "It is now crucial to encourage physicians to carefully balance the benefits and risks when initiating or renewing treatment with benzodiazepines and related products in elderly patients."

The French and Canadian researchers examined data from Quebec from a period of at least six years and identified 1796 cases of Alzheimer's disease which were then individually matched with 7184 healthy people matched for age, sex, and duration of follow-up.

They found that past use of benzodiazepines was associated with a 51% increased risk for Alzheimer's. The link was stronger with longer use of the drugs or use of long-acting versions of the medicines.