Heart disease and cancer may be the two most common direct causes of death in the United States, but a chronic disease that now affects 29.1 million people in this country and is a prime risk factor for heart disease, cancer, and a number of other serious ailments is rightfully beginning to draw a lot of attention. This growing concern is none other than diabetes.

Diabetes prevalence within the U.S. Source: Centers for Disease Control and Prevention.

A growing problem
Diabetes comes in two forms: type 1 and the considerably more common type 2.

Type 1 diabetes is a genetic disorder that manifests during childhood and destroys the cells responsible for insulin production. Insulin is a key component required for us to absorb glucose in order to produce energy. Type 1 diabetes makes up about 5%-10% of all diabetic diagnoses and the disease itself is not preventable.

Source: Flickr user bodytel.

On the other hand, type 2 diabetes can develop at any age and is the result of the body not understanding how to properly use insulin, resulting in glycemic imbalances that can be dangerous over the long run. Unlike type 1 diabetes, type 2 diabetes is potentially preventable or at least its progression can be dramatically slowed by maintaining a healthy lifestyle, eating properly, and maintaining a healthy weight. 

However, with more than a third of the U.S. population considered obese, and around two-thirds overweight based on body mass index, it's no wonder we've seen a rise in diabetes diagnoses over time. Estimates from the Centers for Disease Control and Prevention note that there are 86 million cases of prediabetes just waiting in the wings, and that a frightening one in four diabetics has no clue they have diabetes.

It's a serious long-term disease that clearly needs immediate attention.

Pharmaceutical companies try to do their part
Pharmaceutical companies are certainly doing their part to invest in diabetes research and deliver potentially game-changing products to pharmacy shelves.

Merck's (MRK 1.24%) Januvia (known as Janumet overseas), for instance, is a staple therapy for type 2 diabetics. Januvia's task is to inhibit an enzyme called DPP-4 from removing a hormone called incretin from your body. Incretin is responsible for telling your body to release insulin after you eat.  

Also, a new class of diabetes drugs known as SGLT2 inhibitors began appearing on pharmacy shelves last year. Developed by Janssen Pharmaceuticals, a subsidiary of Johnson & Johnson (JNJ 2.58%), Invokana is an SGLT2 inhibitor that works in the kidneys by blocking the absorption of glucose. The unabsorbed glucose can then be expelled through a patients' urine. SGLT2 inhibitors also exhibited a pleasant side effect in trials of weight loss. Though not indicated on its indication label for weight loss, there is some correlation between being obese or overweight and developing diabetes, therefore a glycemic control drug that could also result in weight loss is very welcome.

Source: MannKind.

Even the "little guy" is getting in on the action. After a complete response letter rejection in 2011, MannKind (MNKD -1.19%) received approval from the Food and Drug Administration for its inhalable type 1 & type 2 diabetes drug Afrezza in August. From a convenience factor the possibility of diabetics no longer having to inject themselves with insulin could be very desirable, although questions on pricing remain prior to its expected launch in the first-quarter of 2015 with licensing partner Sanofi.

An unlikely diabetes treatment
But it's also clear that new pathways need to be explored to help diabetics get a handle on their disease in order to improve their quality of life and reduce their risk of developing serious conditions such as cancer and heart disease.

Yet who would have guessed that one of those potential pathways would lead to an illegal drug?

Source: Flickr user Oswaldo.

According to an abstract study published in The American Journal of Medicine in May 2013, marijuana may play a key role in glycemic regulation.

The study itself involved 4,657 adult men and women, of which 579 were current marijuana users and 1,975 of which had previously used marijuana. The data reaped from the National Health and Nutrition Examination Survey conducted between 2005 and 2010 showed that current marijuana use was associated with a 16% reduction in fasting insulin levels and a 17% reduction in HOMA-IR, a model used by researchers to assess insulin resistance and beta-cell function. Despite the prevailing myth of getting the "munchies" while using marijuana, the waist lines of current users were also narrower than non-users.

Keep in mind, though, that there were other measurements that marijuana didn't have a statistically measurable effect on. For example, HbA1c levels (a measurement of plasma glucose concentrations over an extended period of time) showed only a minuscule drop between non-users and current users, while triglyceride levels in both past and current cannabis users rose slightly.

Moving forward with cannabinoids
If marijuana proves efficacious at helping diabetics control their blood sugar we could be looking at a game-changer. It's one reason why GW Pharmaceuticals (GWPH) and its shareholders are so excited.

Source: GW Pharmaceuticals.

GW Pharmaceuticals is a biopharmaceutical company that's discovered five dozen cannabinoids (chemical compounds derived from cannabis plants) that it plans to use to enact positive biologic change in accord with the cannabinoid receptor systems in our bodies.

One such experimental drug that could garner a lot of attention is that of GWP42004, a type 2 diabetes drug currently in phase 2b studies. In its phase 2a results, reported in late 2012, GW noted statistically significant reductions in fasting plasma glucose levels and improved beta-cell function, with a positive trend in increased insulin sensitivity. It's still a developing drug, but there's certainly promise here on the heels of the aforementioned abstract.

Stay realistic
However, even if medical marijuana provides a pathway to curative treatments for diabetes and other ailments in the future, we as investors have to always keep one aspect of marijuana in mind: it's illegal.

The drug is still classified by the federal government as schedule 1, meaning it has no medical benefits. It doesn't appear as if the federal government plans to change its stance on marijuana as a schedule 1 drug anytime soon, either, despite the fact that it's allowing 23 medical marijuana states and four recreational marijuana states to regulate and tax the product without its involvement.

For investors it means that marijuana stocks, including GW Pharmaceuticals, remain highly risky investments. With medical marijuana's legal future clouded in controversy, and conflicting reports on the benefits and risks of marijuana use over the long run, your smartest move as an investor will likely be to remain on the sidelines.