Millions of people have, of course, taken Valium or some similar tranquilliser, and then settled themselves in a small metal box and spun through the world in their double cocoon composed of one physical barrier and one chemical. But last week researchers from the University of Dundee reported that drowsiness caused by benzodiazepine tranquillisers, of which Valium is the best known, contribute to over 1,500 accidents and more than 100 deaths on the roads each year.
What is remarkable about these findings is that they have taken more than three decades to emerge. The benzodiazepines were introduced in the Sixties and have presumably been causing mayhem on the roads ever since. It seems reasonable to assume, on the basis of this research, that the lives of several thousand people might have been saved if we had drawn the obvious conclusion from the drowsiness that benzodiazepines cause and insisted that patients take other means of transport.
Dr Tom MacDonald, who led the study by the university's medicines monitoring unit, which was published in The Lancet, said: "These drugs have always carried the rather vague warning that they may cause drowsiness and may affect skilled tasks such as driving. Users must be given clear advice not to drive."
This is not the first time that the benzodiazepines, for which 18 million prescriptions were issued in 1997, have been suspected of causing harm. In a now famous edition of That's Life, circa 1980, Esther Rantzen invited patients who claimed to have become addicted to Valium and other tranquillisers to describe their experiences.
Up until that point benzodiazepines had been regarded as wonder drugs by GPs, who handed them out like Smarties to women with small children living in urban tower blocks who were struggling to raise their families on meagre social security benefits. The doctors had dismissed their patients' stories of addiction, believing that the agitation that seemed often to accompany cessation of the drugs was a sign not of withdrawal symptoms but of the return of the anxiety for which the drugs had originally been prescribed.
When Esther Rantzen appealed for other patients with similar experiences to contact the programme, the response was so overwhelming that the doctors were forced to think again. Hundreds of thousands of people were eventually recognised to be addicted to tranquillisers and had to be painfully weaned off them, and the prescribing advice was changed. The committee on safety of medicines now recommends that they be taken for short periods of two to four weeks only, to treat anxiety that is "severe, disabling or subjecting the individual to unacceptable distress."
The episode remains one of the best examples of how patients recognised a problem before their doctors. Richard Asher, the eminent physician and father of the actress, Jane, repeatedly reminded doctors that they should listen to what their patients told them, however outlandish or improbable, as it frequently turned out to be true.
The new evidence that tranquillisers are a menace on the roads illustrates another truth - the need for constant monitoring of the effects of drugs, even decades after their introduction. It also raises a question. Why do we in Britain not run campaigns about the dangers of driving on tranquillisers - as well as other drowsiness-inducing drugs - as is done in Sweden?