Marijuana is a drug that is made up of the leaves, flowers, and buds of the hemp plant Cannabis sativa. Medical marijuana is the use of this drug to help treat symptoms like pain, muscle stiffness (spasticity), nausea, and lack of appetite. It may be used by people who have conditions like cancer, AIDS, or multiple sclerosis.
In the United States, it is against federal law to possess, sell, give away, or grow marijuana for any purpose. It's also against federal law for doctors to prescribe this drug. But more than a dozen states have passed laws that allow people with certain health problems to buy or grow marijuana for their own use. Some states also allow or license people to provide medical marijuana to those who need it.
If you use medical marijuana to treat an approved medical condition, the federal government might not prosecute you. But there's no guarantee.
Medical marijuana laws vary from state to state. If you think you might want to try medical marijuana, talk to your doctor. You can also call your state department of health or health services to learn more about the laws in your state.
What do the experts say?
The medical use of marijuana has been studied for decades. But experts still don't agree on how safe it is or how well it works.
Some medical experts don't recommend marijuana because:
It hasn't been approved by the Food and Drug Administration.
Marijuana may impair your memory, judgment, and coordination. It can increase your risk of being in a car crash.
Marijuana smoke may harm your lungs.
There are legal drugs that may work just as well, such as new kinds of pain and nausea medicines.
Other medical experts do recommend marijuana because:
It can provide pain relief when normal pain medicines don't work or have unwanted side effects.
It can improve appetite and relieve nausea in people who have cancer or AIDS.
It may help relieve symptoms such as pain and muscle stiffness (spasticity) in people who have multiple sclerosis.
Be sure to let your doctor know if you are using medical marijuana. If you're pregnant, it is not safe to use alcohol or drugs, including marijuana.
How do you use medical marijuana?
Marijuana is usually smoked. It can also be brewed into tea, vaporized, applied to the skin, or cooked in food.
You may be affected for hours after you use marijuana. How soon you feel the effects of marijuana and how long they last depends on many things, including:
How much you used.
How you took it.
How your own body responds to it.
Unwanted side effects may include:
Anxiety or paranoid thoughts.
Faster heart rate.
Nausea and vomiting.
Is it addictive?
Some people who regularly use marijuana become addicted. This means that they keep using marijuana even though it's having harmful effects on their lives.
The risk of addiction is higher in people who:
Start using marijuana when they're young.
Use it every day.
Have mental health problems.
People who use marijuana often and then quit may have withdrawal symptoms. These include anxiety, trouble sleeping, and intense cravings for the drug.
Are there alternatives to medical marijuana?
Doctors can prescribe two legal alternatives: dronabinol (Marinol) and nabilone (Cesamet). Both of these drugs contain a man-made form of THC, the main chemical in marijuana.
Nabilone is used to relieve nausea and vomiting caused by cancer chemotherapy. Dronabinol can relieve this kind of nausea and vomiting too. It may also improve the appetite of people who have AIDS. Both dronabinol and nabilone can be used to relieve pain and spasticity in people who have multiple sclerosis. Both drugs come in pill form.
Talk to your doctor if you think these medicines might help relieve your symptoms.
What is synthetic marijuana?
Synthetic marijuana is made of dried plant material that is treated with chemicals that produce effects like marijuana's effects. It is sold in the form of incense under many names, such as K2 or Spice. The labels often claim that these products are "safe" or "natural." But in fact, the active chemicals are created in a lab. And they could be dangerous.
But young people often try these products because they are easy to buy and they may not be detected by drug tests.
People think that using these drugs will make them feel the same as when they use marijuana. But these drugs are different from marijuana. And the effects are hard to predict. That's because the type and strength of the chemicals used are often unknown. Some people have reported severe symptoms, such as:
Fast heart rate and high blood pressure.
Feeling agitated or confused.
Feeling like others want to harm them (paranoia), or seeing or hearing things that aren't there (hallucinations).
Aggarwal SK, et al. (2007). Dosing medical marijuana: Rational guidelines on trial in Washington state. Medscape General Medicine, 9(3): 52. Available online: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2100129.
American Lung Association (2012). Health hazards of smoking marijuana. Available online: http://www.lung.org/stop-smoking/about-smoking/health-effects/marijuana-smoke.html.
Fallik D (2010). As another state approves medical marijuana, neurologists urge caution about prescribing. Neurology Today, 10(4): 1, 5–7.
Johnson JR, et al. (2010). Multicenter, double-blind, randomized, placebo-controlled, parallel-group study of the efficacy, safety, and tolerability of THC:CBD extract and THC extract in patients with intractable cancer-related pain. Journal of Pain and Symptom Management, 39(2): 167–179.
National Cancer Institute (2013). Cannabis and Cannabinoids PDQ – Health Professional Version. Available online: http://www.cancer.gov/cancertopics/pdq/cam/cannabis/healthprofessional.
National Institute on Drug Abuse (2011). Marijuana: Facts for Teens (NIH Publication No. 10-4037). Available online: http://www.nida.nih.gov/marijbroch/teenpg13-14.html.
National Institute on Drug Abuse (2012). DrugFacts: Marijuana. Available online: http://www.drugabuse.gov/publications/drugfacts/marijuana.
National Institute on Drug Abuse (2012). DrugFacts: Spice (Synthetic Marijuana). http://www.drugabuse.gov/publications/drugfacts/spice-synthetic-marijuana.
Accessed September 30, 2013.
National Institute on Drug Abuse (accessed June 2011). Is there a link between marijuana use and mental illness? Research Report Series: Marijuana Abuse. Available online: http://www.nida.nih.gov/researchreports/marijuana/marijuana4.html.
U.S. Department of Justice (2011). DEA Position on Marijuana. Available online: http://www.justice.gov/dea/pr/multimedia-library/marijuana_position.pdf.
U.S. Food and Drug Administration (2006). Inter-agency advisory regarding claims that smoked marijuana is a medicine. Available online: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/2006/ucm108643.htm.
Vijayshree Y, et al. (2014). Summary of evidence-based guideline: Complementary and alternative medicine in multiple sclerosis: Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology, 82(12): 1083–1092.
ByHealthwise Staff Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine Specialist Medical ReviewerMichael Seth Rabin, MD - Medical Oncology
How this information was developed to help you make better health decisions.