America has a problem.

Though prescription drugs are designed to help patients, one class of prescription drugs known as opioids, which are commonly prescribed to relieve severe or chronic pain, have been doing the opposite in certain instances. During periods of extended use, a person can become dependent on opioid medications, leading to a host of possible complications, including overdoses that can lead to death.

According to the Centers for Disease Control and Prevention, between 1999 and 2014 more than 165,000 people died in the United States from overdosing on prescription opioids, such as Methadone, OxyContin, or Vicodin. In 2014 alone, more than 14,000 people died from overdoses tied to prescription opioids, working out to nearly 40 people a day. This is about a 300% increase since 1999, and it's been especially prevalent in persons between the ages of 25 and 54.

There's no denying it: America has an opioid epidemic on its hands.

Could this illegal substance end America's opioid epidemic?

However, researchers at Columbia University's Mailman School of Public Health have an idea on what could be done to curb these unnecessary deaths: Consider the use of medical marijuana.

Based on a new study published in the American Journal of Public Health last week, researchers observed that fewer drivers who tested positive for opioids in states that now have legalized medical marijuana laws than before those laws went into effect were killed in car crashes.

For their study, researchers examined the Fatality Analysis Reporting System data between 1999 and 2013 from 18 states. In all, 68,394 subjects were considered. What really stood out to researchers was the statistically significant reduction of 50% in opioid positivity for drivers between the ages of 21 and 40 in states where medical marijuana was legal.

In the words of lead author June Kim, a doctoral student in the Department of Epidemiology at the Mailman School of Public Health:

We would expect the adverse consequences of opioid use to decrease over time in states where medical marijuana use is legal, as individuals substitute marijuana for opioids in the treatment of severe or chronic pain.

When speaking about the statistical significance of the 21-40 age group, Kim added,

The trend may have been particularly strong among the age group surveyed because minimum age requirements restrict access to medical marijuana to patients age 21 and older, and most medical marijuana patients are younger than 45.

This would imply that if older generations of Americans accepted marijuana as a viable treatment option for severe or chronic pain, opioid overdose death rates could fall further.

However, it's also worth noting that state-specific estimates of all age groups produced only a positive trend, not a statistically significant one. Furthermore, when states were combined, no significant observations were made. Thus, while medical marijuana laws appear to have had a positive impact on the 21- to 40-year-old group in terms of opioid to marijuana prescription switching, the most conclusive determination that can made at this point from researchers is that marijuana "may reduce opioid use and overdose."

Expansion holds promise

On one hand, these findings do hold promise that marijuana could be viewed as a safer alternative to opioids. A handful of previous studies have also demonstrated favorability toward medical marijuana in comparison to opioids.

For example, an abstract published in JAMA Internal Medicine in 2014 found that states that had legalized medical marijuana had significantly lower opioid overdose mortality rates. After examining all 50 states between 1999 and 2010, and paying specific attention to the 13 states that had legal medical marijuana laws on the books during some or all of those years, researchers found a 24.8% lower mean annual opioid overdose mortality rate relative to states that didn't have legal cannabis laws. Furthermore, this opioid overdose mortality rate reduction increased over time, according to the study, from 19.9% in the first year following the approval of medical marijuana laws to 33.3% by the sixth year.

Even more recently we witnessed how beneficial medical marijuana could be in terms of cost savings. A report published by Ashley Bradford and David Bradford of the Department of Public Administration and Policy at the University of Georgia found a correlation between medical marijuana prescription use and lower prescription drug use under Medicare (including, but not limited to, opioids). The authors calculated that medical marijuana saved Medicare Part D $165 million in 2013, and nationwide legalization of the drug could save the program about $470 million annually.

Finally, don't forget that not a single individual died in the United States last year from a marijuana overdose.

But the ceiling is low

On the other hand, medical marijuana could have a very difficult time unseating the opioid epidemic in the U.S. for a variety of reasons.

To begin with, only half of all U.S. states have medical cannabis laws on their books. Medical cannabis is an issue that's reviewed on a state-by-state basis, and there are more than a handful of states that remain wholly opposed to the idea of legalizing the schedule 1 substance. This would mean that access to medical cannabis, and the potential ancillary benefits of reduced opioid overdose mortality rates, will only be available in certain states.

Secondarily, the federal government remains opposed to the idea of recognizing that cannabis has medical benefits. In August the U.S. Drug Enforcement Administration, with the assistance of the Department of Health and Human Services, had the opportunity to review marijuana's scheduling and chose to keep the substance as illicit following its analysis. The DEA suggested that because medical marijuana had no clear medical benefit or safety profile (at least with regard to tightly controlled scientific studies) and its chemical composition is still largely unknown, it would keep the drug as a Schedule 1 substance. This ruling could further constrain consumers' ability to gain access to medical cannabis.

This ruling could also have effectively pushed big potential investors back to the sidelines. As a Schedule 1 substance marijuana businesses face a host of disadvantages, including the inability to take normal corporate income tax deductions, and the struggle to obtain basic financial services from banks and credit unions. Both disadvantages, along with the DEA's ruling to keep marijuana as a Schedule 1 substance, favor small businesses, which makes investing in marijuana a major challenge (and quite risky to boot).

While medical marijuana holds promise in reducing the opioid epidemic in America, it's still no slam dunk.