Medical marijuana advocates have claimed for years that cannabis is an effective and safe alternative to prescription opioids for the treatment of pain. But no one put up the money to prove it until last week.

On Tuesday, the Albert Einstein College of Medicine and Montefiore Health System announced a forthcoming study to ascertain whether medical marijuana can alleviate the need for opioids in both HIV-positive and HIV-free patients who suffer from chronic pain. The National Institutes of Health (NIH) is putting $3.5 million towards the investigation.

A study published last year suggests the Albert Einstein College of Medicine is on the right track.

In 2016, researchers at the University of Michigan published two years' worth of survey results collected from 185 medical marijuana patients suffering from various ailments. Patients reported a 45 percent improvement in quality of life and a 64 percent reduction in the use of prescription opioids.

"We would caution against rushing to change current clinical practice towards cannabis," said Michigan study leader Kevin Boehnke, "but note that this study suggests that cannabis is an effective pain medication and agent to prevent opioid overuse."

The Albert Einstein College of Medicine is right to point out that we have far less data than one might expect, considering the first state to legalize medical marijuana did so 21 years ago. Most research into Schedule I drugs is paid for by the federal government, which has historically underwritten only those studies that either show the harms of such substances or explain their mechanism of action. The federal monopoly on research marijuana, meanwhile, makes studying the drug's therapeutic qualities an exercise in bureaucratic kowtowing.

But we do know there is a correlation between medical marijuana legalization and opioid use. A 2014 study that looked at 11 years of overdose data found that death rates from opioids increased in both states with liberalized marijuana laws and those without, but that "medical cannabis laws were associated with lower rates of opioid analgesic overdose mortality."

When University of Georgia economist David Bradford looked at Medicare prescribing rates, he found that physicians in medical marijuana states prescribed "1,826 fewer doses of conventional pain medication each year."

In addition to receiving funding from NIH—itself a noteworthy development—the Albert Einstein College of Medicine will conduct its study using marijuana provided by New York medical marijuana dispensaries, rather than the moldy ditchweed provided to researchers by the Drug Enforcement Administration's operation at the University of Mississippi.

Cannabis research has turned another corner.