Does weed really have medicinal properties as people say? As the trend to legalize medical cannabis continues, there is growing evidence that it does help relieve some conditions, leading to hopes that it may help curb the US opioid epidemic.

In the US, 28 states plus Washington DC have legalized medical marijuana in some form. An analysis has shown that compared with many other states, those regions spent less money on prescriptions through Medicaid – the healthcare program for people on low incomes – for several conditions sometimes treated with cannabis between 2007 and 2014.  These common conditions were pain, depression, nausea, psychosis and seizures.

The study could not prove that medical marijuana was causing the difference in prescription medication use. But there was no difference found in prescriptions for conditions unlikely to be treated with cannabis, such as antibiotics for infections. At the federal level, weed in plant form is still classed as an illegal drug that has no medicinal properties. This has pushed an increase in cannabis sales, and increasing in the hypothesis that medical weed battles opioid epidemic.

In 2014, the total Medicaid savings that year would in theory have been about $1 billion if they covered medical marijuana fully. However, this pushes costs on to patients, points out. Even in states where medical marijuana is legal, it is not covered by health insurance.

The US is seeing record numbers of deaths from prescription painkillers and illegal opioids such as heroin. Some people become addicted to opioids when they start using prescription painkillers such as oxycodone for a health problem, and later end up switching to illegally obtained prescription medications or heroin.

Beau Kilmer of the think tank RAND Drug Policy Research Center says the latest findings are consistent with most previous research. Some studies have also found correlations between the availability of medical marijuana and fewer opioid overdose deaths.