Want to live forever? Try a little dose of lithium

The notion of living forever has always been an intriguing one for humankind. From the ancients’ search for the elixir of life through Keats’ Ode to a Nightingale ('Thou wast not born for Death! immortal bird’), and from Bram Stoker and Dracula to the Kids from Fame (“I'm going to live forever, I'm going to learn how to fly”), immortality is a constant theme in literature, religion and hackneyed 1980s American TV shows about wannabe stars.

So far from fiction though, humankind's advances in medicine and nutrition have more or less doubled life expectancies in a few centuries, so that we would be regarded as virtually immortal beings by our Victorian or Tudor ancestors. And we now learn that scientists can harness the biology the fruit fly – not, you might suppose the most promising start – to add yet more years to our mortal span. Fruit flies live longer on lithium, you see, which would serve as an excellent advertising slogan were they ever in a position to be marketed to, which, as we know, they are not. Lithium calms the frenetic little things to the extent that they live 16 per cent longer than their undrugged counterparts. Of course nervy humans have been taking lithium for years with no noticeable increase in longevity, but still.

All very well, of course, living to see your great-great-great grandchildren in the turn grow old. But, as we see even today, we would then create the ultimate tragedy of the commons, so that the unending supply of humanity would eventually consume all that was available, outstripping any conceivable increases in productivity.

Perhaps then we would turn to a science fiction world where everyone is allowed to live forever, but where no-one can be born. Immortality will never be easy.