Marijuana is the term commonly used for the Cannabis sativa plant. (1) Despite being legal in 23 states and Washington, D.C., cannabis is still federally classified as a Schedule I drug, meaning that it has a high abuse potential and no medical use currently accepted by the U.S. government. (2) Other Schedule I drugs include heroin and 3,4-methylenedioxymethamphetamine (ecstasy), while cocaine and methamphetamine (meth) are Schedule II drugs, since they have an officially recognized medical use. (2)
As crazy as this may sound, it’s harder for scientists to conduct studies on marijuana than on cocaine or meth. College students routinely administer methamphetamine to rodents in their science classes, but if they are caught with cannabis, they may face serious disciplinary—or even legal—consequences.
The Differences between Cannabis, CBD, and THC
The terms “marijuana” and “cannabis” both refer to any of the subspecies of the whole, unprocessed Cannabis sativa plant and its basic extracts. (3) Cannabidiol (CBD) and delta-9-tetrahydrocannibidol (THC) are chemical compounds found in the cannabis plant that are of particular medical interest. These chemicals and those that resemble them are known as cannabinoids. (3) THC is the psychoactive chemical in cannabis responsible for much of the “high” that users feel; CBD, however, is non-psychoactive and does not produce the physiological responses that THC does. (4, 5)
However, there are numerous other areas in which cannabis and cannabinoids could prove beneficial to people’s health and well-being.
Four promising uses for medical marijuana…
Endocannabinoid Receptors Suggest Potential Targets and Applications for Medical Cannabis
The known functions of our bodies’ endogenous cannabinoids and endocannabinoid receptors suggest possible therapeutic targets for medical cannabis.
Endocannabinoid receptors have been linked to the regulation of appetite, pain management, neuroprotection, central regulation of motor functions, sleep, regulation of nausea and vomiting, reward-driven neurocircuitry, intraocular pressure, memory, tumor growth, and gastrointestinal motility. (7)
One specific type of endocannabinoid receptor, CB1, is known to stimulate appetite and ingestive behaviors. (7) This effect is responsible for the snacking behavior—or “munchies”—caused by recreational cannabis use. It is also the reason that cannabis can be used medically to increase the appetites of patients with AIDS or those who are undergoing chemotherapy, as mentioned before, while also reducing nausea and vomiting among those groups. Cannabis’s appetite-stimulating effects could also be used to treat age-induced anorexia in the elderly in general, and specifically for those with Alzheimer’s disease. (8) Cannabinoids may also be able to slow the disease process of Alzheimer’s by preventing inflammatory effects induced by the beta-amyloid deposition that is a hallmark of the disease. (9)
Endocannabinoid receptors have been shown to reduce pain from a variety of causes. The analgesic effects of acetaminophen can be prevented by blocking specific cannabinoid receptors. (10) Cannabis extracts containing THC alone and THC with CBD have proved effective at reducing chronic and neuropathic pain. (11) Many people with multiple sclerosis (MS) who use cannabis report a reduction in symptoms, including muscle spasticity, pain in extremities, tremor, bowel dysfunction, and walking and balance dysfunction. (12) This may be due to cannabis’s role in pain, motor control, and gastrointestinal motility.
Conditions for Which Medical Cannabis Shows the Most Promise
- PTSD. While anti-drug crusaders frequently cite the detrimental effects of cannabis on memory (13), there are certain populations for which this effect would be a good thing. People suffering from post-traumatic stress disorder (PTSD) could benefit from the memory-weakening effects of the drug. Nabilone, the cannabinoid drug approved for the treatment of anorexia and nausea among cancer and AIDS patients, is associated with a cessation or reduction in the intensity of nightmares in a majority of PTSD patients surveyed. (14) New Mexico was the first state to allow usage of medical cannabis to treat PTSD, and one study done within in the state revealed a 75 percent reduction in symptoms among participants with PTSD. (15)
- Cancer. Cancer and AIDS patients are the two populations for which medical cannabis or cannabinoid use has become most widely accepted. Nabilone and dronabinol have been approved for treatment of anorexia, cachexia, nausea, and vomiting in cancer patients undergoing chemotherapy since the 1980s. (16) Newer research has revealed an even more exciting use of cannabis for cancer patients: cannabis may be able to treat the cancer cells themselves. Cannabinoids induce cell death, inhibit cell growth, and slow metastasis in tumor cells without harming the surrounding non-cancerous cells. (16) In a mouse model, pure THC and CBD were shown to prime glioma cells—a cell found in certain types of brain cancer—for radiation therapy, making them more sensitive to and easily destroyed by irradiation. (17) Studies like these show that cannabis may have a broader application for cancer patients than previously thought.
- Multiple sclerosis (MS). Cannabis can provide relief for multiple symptoms of MS, as discussed above, but it has shown the most promise for treating spasticity. Spasticity refers to the feelings of stiffness and involuntary muscle contractions experienced by people with MS, and it is one of the most common symptoms of the disease. (18) The endogenous cannabinoid system may be active in controlling spasticity, as indicated by exacerbation of this symptom in a mouse model of MS following blockage of endocannabinoid receptors. (19) In humans with MS, both whole plant cannabis-based medicine and an extract combining THC and CBD may reduce the number and severity of spastic episodes. (20, 21) Despite being one of most common symptoms of MS, spasticity has remained difficult to treat with most drugs currently on the market, making cannabis a very intriguing option for treatment.
- Treatment-resistant epilepsy. Cannabis has been used for millennia in the treatment of epilepsy, but it has only recently been investigated seriously by scientists for safety and effectiveness in this use. In particular, research has focused on cannabis use for childhood epilepsy that has shown resistance to current treatments. While cannabinoids have produced mixed results in animal models of epilepsy (22), CBD has been associated with a decrease in seizure frequency in a recent human study among participants with childhood-onset treatment-resistant epilepsy. (23) Additionally, the safety profile of CBD makes it an attractive treatment for epilepsy in children and young adults. The side effects of antiseizure drugs can be brutal for kids, and a growing number of parents have turned to CBD as an effective and much better tolerated alternative. More research and clinical trials are needed on this application of medical cannabis, but more than 4,000 years of anecdotal support for its efficacy in treating seizures have provided hope for many.
A Changing Legal and Social Environment
Once a niche area with limited scientific interest, the field of cannabis research has expanded rapidly in the last decade. Much of the research continues to focus on cannabinoids, rather than whole, unprocessed cannabis. Support for the use of whole cannabis comes from anecdotal evidence as much as from empirical scientific research, but research is slowly beginning to confirm or disprove those anecdotal claims. Cannabis’s current classification as a Schedule I drug by the U.S. government, as well as the attached social stigma, continues to limit the ability and willingness of researchers to investigate all of its possible uses. But as more states approve cannabis for medical and/or recreational use, research and funding will likely continue to expand.
The National Institutes of Health (NIH) currently provides funding to more than forty active projects in the category of Therapeutic Cannabinoid Research. (24) Projects include investigations into the potential of transdermal CBD to reduce the chance of relapse in abstinent alcoholics (25), the ability of vaporized cannabis and dronabinol to reduce neuropathic back pain (26), and the role of the endocannabinoid system in radiation and chemotherapy-induced cognitive impairment and possible methods for prevention or treatment (27), among many others.