What is medical marijuana or medical cannabis?

Medical marijuana is the medical use of the Cannabis sativa or Cannabis indica plant to relieve symptoms of or treat diseases and conditions. The Cannabis plant was used medically for centuries around the world until the early 1900s. Medical marijuana facts can be difficult to find because strong opinions exist, both pros and cons. Medical uses and emerging research on off-label uses are summarized in this article.
What are THC and CBD?
THC or Tetrahydrocannabinol
THC or tetrahydrocannabinol is the psychoactive compound in marijuana. It is responsible for the "high" people feel. There are two man-made drugs called dronabinol (Marinol) and nabilone (Cesamet) which are synthetic forms of THC. They are FDA-approved to prevent nausea and vomiting in people receiving chemotherapy.
CBD or Cannabidiol
CBD or cannabidiol is another compound in marijuana that is not psychoactive. CBD is thought to be responsible for the majority of the medical benefits.
Epidiolex is a CBD oil extract that is undergoing clinical trials for epilepsy.
THC: CBD
Nabiximols (Sativex) is a specific plant extract with an equal ratio of THC: CBD. It is approved as a drug in the UK and elsewhere in Europe for the treatment of multiple sclerosis, spasticity, neuropathic pain, overactive bladder, and other indications.
Medical marijuana products are available with a huge range of THC and CBD concentrations. The expert opinion states that 10mg of THC should be considered "one serving" and a person new to medical marijuana should inhale or consume no more until they know their response.
What are the uses for medical marijuana?
Medical uses of marijuana include both studied and approved uses and off-label uses.
In a recent research survey, the most common reasons people use medical marijuana include:
- Pain
- Anxiety
- Depression
- Muscle spasticity
- Inflammatory bowel diseases such as Crohn's disease
More research has been conducted on the compound CBD. Medical CBD is anti-inflammatory, anticonvulsant, antioxidant, neuroprotective, anxiolytic, antipsychotic, and anti-emetic. The CBD compound in medical marijuana appears to be neuroprotective in Huntington's, Parkinson's, and Alzheimer's disease, fetal hypoxia, and other neurodegenerative conditions and movement disorders.
What are the health benefits of medical marijuana?
There are over 60 peer-reviewed research studies examining the benefits of medical marijuana. Sixty-eight percent of these studies found benefit while 8% found no benefit. Twenty-three percent of the studies were inconclusive or neutral. Most research has been conducted on the compound CBD.
The benefits of medical marijuana can be attributed to binding to the endocannabinoid system and may include:
- Modulating the immune system
- Promoting neuroplasticity
- Emotional and cognitive modulation including learning and motivation, appetite, vascular function, and digestive function

SLIDESHOW
What Is Pot? Medical Marijuana Laws, Uses, Safety See SlideshowAre there any side effects of medical marijuana?
Medical marijuana side effects are minimal when used at low doses and include:
At higher doses, side effects include:
- Dizziness
- Paranoia
- Psychoactive effects include mood changes and hallucinations
There are concerns about the adverse effects of cannabis among adolescents because the risks are greater to the immature brain and neurological system. Concerns include an increased risk of schizophrenia and loss of IQ.
There are public health concerns about the safety of driving under the influence of medical marijuana. A JAMA study found lower rates of opioid overdose deaths in states with legal medical marijuana.
Is medical marijuana legal?
At the time this article was written, 23 states had legalized medical marijuana with varying restrictions. However, it is classified as a Schedule I substance by the Federal Drug Administration (FDA) and thus is illegal at the Federal level. In most states with legal medicinal marijuana, a prescription, authorization, or medical recommendation is required, and a card or license is issued. This allows a person to buy medical marijuana.
How do you get medical marijuana?
In states where medical marijuana is legal, shops, often called dispensaries, sell marijuana products in a variety of forms, such as:
- Edible forms (candies or cookies)
- Oils
- Extracts
- As the plant which can be smoked or otherwise inhaled
Dispensaries require a medical marijuana card before they will sell products. How people can get a medical marijuana card varies by state. It requires a prescription from a licensed healthcare professional.
Is medical marijuana "addictive?"
Most research suggests a very low risk of addiction and very low toxicity of medical marijuana when taken as recommended in low therapeutic doses. There is concern about psychological dependence in heavy users and whether this constitutes marijuana abuse. Some research has suggested CBD oil might be useful in the treatment of marijuana addiction or marijuana abuse.
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Fernández-Ruiz, J. et al. "Cannabidiol for neurodegenerative disorders: important new clinical applications for this phytocannabinoid." Br J Clin Pharmacol. 2013 Feb;75(2):323-33.
Sexton, M., et al. "A Cross-Sectional Survey of Medical Cannabis Users: Patterns of Use and Perceived Efficacy." (Under Review 2016: Cannabis and Cannabinoid Research).
Murnion, B. "Medical Cannabis." Aust Prescr. 2015 Dec; 38(6): 212–215.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4674028/
Bachhuber, MA., et al. "Medical cannabis laws and opioid analgesic overdose mortality in the United States." 1999-2010. JAMA Intern Med. 2014 Oct;174(10):1668-73. Erratum in: JAMA Intern Med. 2014 Nov;174(11):1875.
Allsop, DJ., et al. "Nabiximols as an agonist replacement therapy during cannabis withdrawal: a randomized clinical trial." JAMA Psychiatry 2014;71:281-91.
Brunt, TM., et al. "Therapeutic satisfaction and subjective effects of different strains of pharmaceutical-grade cannabis." J Clin Psychopharmacol. 2014 Jun;34(3):344-9.
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