Researchers have found positive correlation between the legalisation of cannabis and a decline in opioid deaths over a study period of 20 years.

The study, by the University of Massachusetts Amherst, suggests that opioid-related fatalities have reduced by somewhere in the region of 20 to 35 per cent where marijuana laws have eased.

Researchers only investigated recreational marijuana laws, however, and did not consider the impact of medicinal cannabis laws on opioid mortality.

The report’s co-author, Dr Nathan Chan, said: “Recreational marijuana laws affect a much larger population than medical marijuana laws, yet we know relatively little about their effect.

“Focusing on the recent wave of recreational marijuana laws in the US, we find that opioid mortality rates drop when recreational marijuana becomes widely available via dispensaries.”

The study, published in the Economic Inquiry, comes amid increasing pressure on politicians to legalise recreational cannabis.

Bernie Sanders, the 2020 presidential candidate, promised to use special presidential powers to enforce nationwide legalisation of cannabis on the Joe Rogan podcast recently.