Source: Flickr user PabloEvans.

You won't find many issues as polarizing as what should be done with marijuana, legally speaking.

On one hand, marijuana's momentum appears unstoppable. According to Gallup, more people favor legalizing the drug than not. Additionally, states like Colorado and Washington have been able to double-dip when it comes to tax revenue as medical marijuana and recreational marijuana have both been legal within those states for two years. Revenue from marijuana taxation can help fill budget gaps, including gaps that otherwise could mean layoffs of state-employed workers.

Then again, much is still unknown about marijuana and its long-term side effects. This is partly because most research surrounding marijuana has sought to examine its dangers rather than its benefits. Marijuana is also classified as a schedule 1 drug by the federal government, meaning it's illicit and purportedly carries no medical benefits.

As I said, it's a polarizing issue, and the pendulum seems to swing a different way each week.

This past week, it swung largely in support of marijuana's possible legalization.

Source: Flickr user

Big news for marijuana supporters
According to a study published in the journal Scientific Reports, researchers examined the ratio of toxicity and human intake for a number of legal and illegal "drugs," including alcohol and tobacco, and discovered that marijuana was by far the least dangerous drug of them all.

In order to establish the rankings, researchers compared the estimated lethal dose of seven drugs to an estimated level of human intake. On an individual basis, the team of international researchers observed that alcohol was the deadliest substance. Also placing in the high-risk category were heroin, cocaine, and tobacco. Researchers noted that ecstasy and meth carried medium risk based on the ratio of toxic dose to human intake. However, the only drug to rate as low-risk, and deemed to be 114 times less deadly than alcohol, was cannabis!

As international researchers commented:

The results confirm that the risk of cannabis may have been overestimated in the past. At least for the endpoint of mortality, the margin of exposure for THC/cannabis in both individual and population-based assessments would be above safety thresholds. In contrast, the risk of alcohol may have been commonly underestimated.

As The Washington Post also noted, the results mirror findings from researchers a decade ago, who determined that cannabis represented a relatively low-risk drug compared to other illegal substances.

Bigger news for recreational and medical marijuana
Not only does this news appear to validate a long-standing position from marijuana supporters that the drug is safe (at least from a mortality risk perspective), it's even more important for the recreational marijuana movement and for cannabinoid-based drug developers.

According to NerdWallet, which utilized data from the Substance Abuse and Mental Health Services Administration and the Tax Foundation, a sweeping legalization of marijuana across all 50 states (recreational and medical) would generate a whopping $3.1 billion in tax revenue if an excise tax of 15% were used uniformly. Obviously, taxes are likely to differ in each state, and some states are clearly more likely to legalize than others, but it does demonstrate just how powerful a tool marijuana's tax revenue could be when it comes to closing budget gaps.

Source: GW Pharmaceuticals.

Perhaps even more intriguing is what this study could do for marijuana research as it pertains to disease. Marijuana is commonly prescribed as a treatment for cancer pain and glaucoma in the 23 states where the drug has been deemed medically legal, but drug developers such as GW Pharmaceuticals (GWPH) have far bigger plans in mind for marijuana.

GW Pharmaceuticals has discovered more than five dozen cannabinoids from the cannabis plant to date and plans to use those cannabinoids, which work along a natural cannabinoid receptor system found in our bodies, to achieve desired biological outcomes. Currently it has just one approved drug, Sativex, in more than a dozen countries outside of the U.S., but it's thinking larger.

Perhaps the company's most promising study involves that of investigational drug Epidiolex as a treatment for two rare forms of childhood onset epilepsy known as Dravet syndrome and Lennox-Gastaut syndrome. In trial results released last year, GW Pharmaceuticals noted that seizure frequency was reduced by 56% for Dravet syndrome patients, and 52% for Lennox-Gastaut syndrome patients. Since these patients are usually children, the news that marijuana could be safer than initially thought is extremely encouraging.

Keeping things in perspective
Despite what can only be described as positive results from this latest study, we still need to keep a few things in perspective.

Source: Michigan Municipal League via Flickr.

First, even if additional data continues to be gathered in favor of marijuana's safety, change at the federal level is likely to be slow. Consumers and potential marijuana investors here have to understand that nearly three decades of research was focused on marijuana's risks and not its benefits. In the mind of regulators, I believe it's going to take a substantial amount of data and time before any lessening of marijuana's classification as a schedule 1 drug can be considered. This means marijuana's explosive growth potential on a recreational level is likely to be tamer than some are expecting.

Second, consumers and potential investors need to understand that just because marijuana's risk of mortality due to overdose is extremely low, that doesn't mean it's without side effects at all. The active agent of marijuana, THC, has been shown in previous studies to negatively impact cognition, memory, and decision-making skills.

Again, I want to emphasize that additional studies are ongoing into marijuana's short- and long-term effects on cognition, but the fact remains that it does have some effect on our body, and until these effects are more widely studied, marijuana's expansion for recreational and medical purposes could be minimal.

Finally, I can't help but suggest investors exercise extreme caution with the marijuana industry as a whole. Few marijuana stocks are traded on reputable exchanges such as the NYSE or Nasdaq, meaning the regulations that require them to disclose their performances on a quarterly basis aren't there. In many instances, finding out even basic information about a company can be an exhausting and disappointing task.

Additionally, most marijuana stocks are money losers. Even GW Pharmaceuticals, arguably the most visible "marijuana stock," is likely to lose money throughout the remainder of the decade.

In my opinion, this continues to be a sector best left untouched by your investment dollars.