The drugs are known as "a chemical cosh" because they are an easy way to control patients, especially if they are elderly and become agitated. Prescribing the drug is often the first thing hospital staff do, when it should be the last, according to guidelines that state that a non-pharmacological approach should be tried first to treat anxiety, agitation and insomnia.

But while it's a quick and easy solution for hospital staff, it can be a fatal one for the patient, say researchers from the University of Eastern Finland. The drugs increase the risk of death by 40 per cent in the Alzheimer's patient, and the risk can come as a direct consequence of taking the drug, or indirectly from a fall because the patient loses physical control. Overall, the main causes of death are hip fractures after falling, pneumonia and stroke.

The researchers looked at earlier studies that had tracked the progress of 10,380 patients who had recently been put on a drug, and compared them to 20,760 other patients who weren't taking a benzodiazepine. The risk started from the very first day the drug was prescribed, the researchers found.

Aside from the bad practice of making the drugs the first act—instead of the last—the researchers also found that hospitals were prescribing the drugs for very long periods, when they should be given for only a few days at a time.