Nearly half a century ago, in 1965, the Rolling Stones wrote a song called Mother’s Little Helper. The words went:

Kids are different today, I hear ev’ry mother say

Mother needs something today to calm her down

And though she’s not really ill, there’s a little yellow pill

She goes running for the shelter of a mother’s little helper

And it helps her on her way, gets her through her busy day…

They continued:

And if you take more of those

You will get an overdose

No more running for the shelter of a mother’s little helper

They just helped you on your way

Through your busy dying day…

The pill was valium (diazepam) and the yellow pill was 5 milligrams – as it still is. White is 2 milligrams and blue is 10.

The song was not great poetry, perhaps, but for pop music it was prescient pharmacovigilance, the epidemiological study of the adverse effects of drugs: though strictly speaking overdoses of diazepam are not dangerous. Many thousands of people have taken overdoses of diazepam in attempts to kill themselves with it, but few have succeeded unless they took something else with it.

However, it has long been known that diazepam and other similar drugs cause falls in the elderly, and such falls are often the precursor of death. It has also been suspected that, by some unspecified mechanism, diazepam (and sleeping draughts of all kinds) promote death.

A paper in a recent edition of the British Medical Journal compares the death rates of primary care patients who were prescribed diazepam-like medicines and hypnotics with those who never were prescribed them more than once (they excluded patients who had been prescribed them only once because it was possible that they had never taken them, which was unlikely if they were prescribed them twice). The authors compared the records of 37,000 of the former with 63,000 of the latter. They attempted to match them for such variables as age, social class, sex, and medical and psychiatric history. They followed the patients for an average of 7.6 years.