This New Study Is Bad News if You're a Marijuana Supporter

Source: Flickr user Tom Booth.

Marijuana legalization may not be a top priority of Congress or President Obama, but the American public is certainly doing its best to make it apparent that marijuana is an important issue.

We've seen a complete transformation of the American public's opinion of marijuana and even individual state law over the past two decades. What once was an illegal substance in all 50 states is now legal from the aspect of medical purposes in 23 states, and legal from a recreational, adult-use standpoint in four states.

The driving force behind marijuana's expansion Opinion concerning marijuana among the public has been the driving force, with Gallup's and the General Social Survey's latest marijuana opinion polls suggesting that, for the first time ever, a majority of the public favors the legalization of marijuana. In polls that separate the idea of medical marijuana legalization from recreational legalization, medical marijuana typically boasts a higher percentage of public support.

Source: Flickr user Rafael Castillo.

This support was on display earlier this week, when a Quinnipac poll was released that showed the states of Florida, Ohio, and Pennsylvania favored the recreational and medical legalization of marijuana. Per Quinnipac's survey, 55% of Floridians, 52% of Ohio voters, and 51% of Pennsylvania voters favor a sweeping legalization of marijuana. When it pertained to just medical marijuana, the support jumps to 84% in Florida and Ohio, and a whopping 88% in Pennsylvania.

Growing support for marijuana is what inspired three senators to introduce the CARERS Act last month -- a bill that would eliminate the federal ban on medical marijuana.

The basic premises of the CARERS Act include the rescheduling of marijuana as a schedule 2 drug from schedule 1 (i.e., admitting it has medical benefits, but is prone to abuse), the allowance of banks to make loans to medical marijuana businesses without the fear of legal action from the federal government, and the loosening of the hurdles tied to marijuana research, potentially allowing cannabinoid-based drug developers such as GW Pharmaceuticals to more easily research marijuana's potential benefits.

How far the CARERS Act will wind up going in Congress is really anyone's guess, as it's the very first medical marijuana bill introduced on a federal level.

Legalizing marijuana could be a distant "memory" However, based a new long-term study of cannabis use in adolescents and young adults, marijuana's risk profile could be one factor that stops federal legalization of medical marijuana from happening.

Based on a recently released study in the journal Hippocampus, researchers at Northwestern University announced potentially worrisome findings regarding the heavy use of marijuana as an adolescent on users' long-term memory.

Source: National Cancer Institute, Facebook.

For its study, Northwestern University examined daily marijuana users who began at age 16 or 17 (and used marijuana for a period of three years) and pitted those individuals against same-age young adults that had never used marijuana. Researchers then examined MRI scans that focused on the area of brain responsible for long-term memory retention, the hippocampus. To attempt to be as fair as possible, researchers conducted these MRI scans on subjects in their early 20s who were two years removed from their heavy marijuana use. The findings of the study showed an oddly shaped hippocampus in heavy marijuana users accompanied by an average long-term memory test score that was 18% lower than young adults who'd never used marijuana before. This odd formation was not observed in the non-user group.

As senior author Dr. John Csernansky stated, "The memory processes that appear to be affected by cannabis are ones that we use every day to solve common problems and to sustain our relationships with friends and family." Also noted, this was the first study to confirm a link between heavy marijuana use and a misshapen hippocampus that led to poor long-term memory performance.

This study comes on the heels of a 2013 study released by Northwestern University that suggested heavy marijuana users' short-term memory may be affected because of abnormalities in heavy users' sub-cortex.

A challenging road for marijuanaIt's fairly obvious based on polls that a good chunk of Americans are in favor of loosening federal marijuana laws. But the reality is that change (should it come at all) is probably going to come slowly until physicians and researchers feel more comfortable about prescribing marijuana for potentially long-term and chronic diseases.

Source: Flickr user Gabor Basch.

It may not be "fair" that for decades researchers focused on marijuana's risks while few studies looked at its potential benefits, but that's the reality of the data that lawmakers and researchers are currently working with. Marijuana may have shown potential benefits in treating type 2 diabetes, aggressive brain tumors, and certain types of epilepsy, but it's the potential damage to our brains over the long term that generally has researchers and lawmakers concerned.

For GW Pharmaceuticals, which would really enjoy seeing laws relaxed around marijuana research, it likely means the lofty hurdles that need to be cleared prior to testing its cannabinoids aren't going away anytime soon. Ultimately, that may not matter all too much for GW Pharmaceuticals, which has six drugs being tested in a nine different indications, along with one approved product, Sativex, in about two dozen markets outside the United States. Its pipeline is deep enough that a continuation of the arduous drug development process for years likely wouldn't even phase it or investors.

Although public opinion suggests marijuana could be a great investment, the uncertainties surrounding conflicting study data and federal lawmakers' low priority for marijuana continues to weigh on its opportunity to expand. As such, until the federal government does change its stance on medical marijuana, or until more studies on the benefits of medical marijuana are presented, I'd suggest keeping your distance from marijuana stocks in general.

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Sean Williamshas no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen nameTMFUltraLong, track every pick he makes under the screen nameTrackUltraLong, and check him out on Twitter, where he goes by the handle@TMFUltraLong.The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

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