Image source: Flickr user Craig Sunter. 

Diseases like cancer may garner the most attention from drug developers and researchers because of its mystery, the current lack of a cure, and its high mortality rate. However, that doesn't mean other diseases aren't in need of addressing that have an even higher cost to our healthcare system and business productivity.

The chronic pain epidemic
One such ailment is chronic pain. By definition, pain is considered chronic when it last for six months or longer. The pain level an individual experiences can vary from being mild or dull to downright debilitating. According to the American Academy of Pain Medicine, as of 2011 at least 100 million adults Americans (we're talking close to half the adult population) had common chronic pain conditions. The direct medical costs and economic costs for lost productivity from chronic pain on this many people ranges between $560 billion and $635 billion annually (based on 2010 dollars), which works out to nearly $2,000 for every man, woman, and child in the United States.

Image source: National Institute on Drug Abuse.

With pain being the leading cause of disability in the U.S., more consumers than ever are turning to their doctors and pharmacies for assistance. It's become so commonplace that in January 2015 the National Institutes of Health proclaimed that chronic pain treatments have become a "silent epidemic," with consumers becoming addicted to opioid-based therapies. The NIH urged physicians to look at nonpharmacological approaches to chronic pain management in lieu of the dangers of most opioid-based one-size-fits-all therapies, and the fact that more than 15,000 people overdose each year from accidental or intentional opioid misuse. 

But what if there were another therapy available that safely treated chronic pain without the concern of an overdose that's apparent with opioid-based therapies? This is exactly what was on the minds of researchers in Canada who conducted a long-term experiment on chronic pain patients who did and did not use marijuana over the course of a year to treat their symptoms.

Did researchers just give marijuana the green light?
As published in the Journal of Pain in September, researchers at the Research Institute of the McGill University Health Center in Montreal, Canada, followed 215 adult patients with chronic non-cancer pain who used medical cannabis daily and 216 adults who didn't use cannabis for a period of one year. The study, which ran between 2004 and 2008, demonstrated that medical marijuana presented no worse a safety profile than the group that did not use medical marijuana when it comes to serious adverse events. It should be noted here that it's practically impossible to overdose on marijuana, meaning a push to use the currently illegal drug to treat chronic pain could (key word here) substantially reduce accidental overdose deaths.

Lead researcher Dr. Mark Ware had the following comment:

We found that medical cannabis, when used by patients who are experienced users, and as part of a monitored treatment program for chronic pain over one year, appears to have a reasonable safety profile.

Image source: National Drug and Alcohol Research Centre.

However, researchers refrained from giving marijuana the green light for treating chronic pain. Study results also showed a number of non-serious side effects increased with daily marijuana use, such as headaches, dizziness, and respiratory issues, which were most prevalent in persons smoking marijuana on a daily basis.

Additionally, the subjects of the study were self-selected, and the researchers didn't control for tobacco usage, which can play a role in the side effects presented by both the marijuana and control cohort. Thus, researchers suggested that caution be given when smoking marijuana (as opposed to edibles, for instance) and that because the study focused on experienced marijuana users, there's no telling what sort of safety profile it might have on new users.

In other words, like many trials before it, this study has its limitations.

Marijuana is no slam-dunk treatment for chronic pain
Although chronic pain is a common ailment covered by the nearly two dozen states that have legalized medical marijuana across the United States, there are still no guarantees that marijuana is the best treatment course for patients.

On the one hand, we do have pretty undeniable evidence that its overdose profile is considerably more attractive than opioids. Furthermore, the study out of Canada appears to be on par with a 2011 study from the University of California San Francisco that suggested adding cannabinoids from the cannabis plant to an existing opioid-based treatment regimen could be more effective and allow the patient to take a lower dose of opioid, thus presumably lessening the chance of an overdose. 

Image source: GW Pharmaceuticals.

However, existing cannabinoid-based therapies simply may not be effective. GW Pharmaceuticals (NASDAQ:GWPH), arguably the leading company when it comes to cannabinoid research (it's discovered more than five dozen cannabinoids), watched in disbelief when it and collaborative partner Otsuka Pharmaceutical in January announced that its first of three planned late-stage studies of Sativex as a treatment for chronic pain caused by advanced cancer failed to provide a statistically significant difference from the placebo. Though there are still two studies ongoing, this isn't a good start for Sativex in cancer pain, and it's a surprising failure for a marijuana-based product.

The door for marijuana to become a viable treatment option for chronic pain certainly remains open, but questions surrounding its efficacy and delivery options (those aforementioned non-serious adverse effects from smoking medical marijuana) do raise concerns among researchers and physicians.

Without any expected change in stance from the federal government, and the industry still struggling under the weight of unfavorable tax and banking laws, as well as a considerably less expensive and more expansive black market of marijuana growers, I'm going to have to suggest that investors continue to keep their money safely on the sidelines and away from marijuana stocks.