When tackling societal problems - like the opioid epidemic in the US - there are two ways of approaching it. One is to reduce demand - by organising treatment programmes, or reducing the underlying reasons why people may become addicted in the first place - but that’s hard. So governments often turn to the other route - reducing supply - and that’s what the US government did in 2014 when it rescheduled oxycodone combination products from schedule 3 to schedual 2 - essentially making it harder for people to obtain a prescription.

Now reducing that legal supply, without in hand reducing the demand, led to fears that those people with an opioid addiction would just turn to illicit routes to obtain their drugs - and new research published on bmj.com has attempted to find out if that happened.

We're joined by 3 of the authors, James Martin, associate professor of criminology at Swinburne University; Judith Aldridge, professor of criminology at the University of Manchester; and Jack Cunliffe, lecturer in quantitative methods and criminology at the University of Kent.

Read the full research: