While the US suffers an overdose epidemic, much of the rest of the world misses out on vital painkillers.

90% of all the morphine on the planet is consumed by the world's richest 10%, according to a commission set up by medical journal The Lancet – so what's behind the global pain divide?

You can listen to The Inquiry: Are We Missing a Bigger Opioid Crisis? on the BBC World Service, or download the programme podcast, to find out more.