Medical Marijuana: Facts about cannabis, THC, and CBD - Harvard Health (2024)

Doescannabis really offer the health benefits you hear so much about?

Or, Is The Hype More than the Hope?

Learn the Facts With The Expert Information On Every Page OfMedical Marijuana: Facts about cannabis, THC, and CBD​

What You Need To Know From The Most Trusted Source In Health Information—Harvard Health Publishing

Does medical cannabis work? If you ask people who use it, many will enthusiastically report that it does. However, the evidence remains somewhat fragmented, incomplete, and uncertain. Additional research is underway, but there remains many unanswered questions.

But what are the facts? What are the proven benefits, and what are the risks? What’s the right dose, and how do you determine the quality of what you are taking? Do the products you might use even contain the ingredients they promise?

Don’t take chances with your health. Get accurate answers straight from the experts at Harvard Medical School in Medical Marijuana, an all-new report you can download right now.

  • Pain? Studies show that medical marijuana can help ease persistent pain.
  • Trouble Sleeping? There is moderate evidence that medical marijuana may help disturbed sleep associated with sleep apnea, fibromyalgia, chronic pain, and MS.
  • Nausea and Vomiting? There are FDA-approved cannabinoid-based prescription drugs that can help with side-effects from chemotherapy when other medications don’t.

Download the report right nowand get the facts and dispel the rumors! Learn the history and science behind this ancient plant and be well-prepared for a conversation with your doctor.

Prepared by the editors of Harvard Health Publishing in conjunction with Staci Gruber, PhD, Associate Professor of Psychiatry, Harvard Medical School and Director, Cognitive and Clinical Neuroimaging Core, and Director, Marijuana Investigations for Neuroscientific Discovery Program, McLean Hospital. (2024)

About Harvard Medical School Guides

Harvard Medical School Guides delivers compact, practical information on important health concerns. These publications are smaller in scope than our Special Health Reports, but they are written in the same clear, easy-to-understand language, and they provide the authoritative health advice you expect from Harvard Health Publishing.

Prepared by the editors of Harvard Health Publishing in consultation Staci Gruber, PhD Associate Professor of Psychiatry, HarvardMedical School Director, Cognitive and Clinical Neuroimaging Core, and Director, Marijuana Investigations for Neuroscientific Discovery (MIND) Program, McLean Hospital. 23pages (2023)

How to obtain medical cannabis

If you want to get permission to legally use medical cannabis under a medical marijuana program, it’s important to fully understand the terms of your state’s medical marijuana law or program. Whether you can access medical cannabis depends on what state you live in. The following information applies specifically to cannabis products obtained under state medical marijuana programs—not to hemp-derived (mostly CBD) products for sale online and in the general marketplace.

Comprehensive programs provide patients with legal protections, practical access to a variety of cannabis preparations, a variety of ways to administer cannabis products, and ongoing, public access to the program.

An additional 15 states have restricted, noncomprehensive programs. Many of these provide access to only low-THC, high-CBD cannabis preparations— for example, to treat seizures.

The National Conference of State Legislatures website maintains a list of state programs with links to the text of the laws themselves. It’s a good place to start educating yourself about medical marijuana laws: www.ncsl.org/ research/health/state-medical-marijuana-laws.aspx. Your state, if it has a medical marijuana law, may also have online information about the program. Following are some of the fundamentals of state medical cannabis laws and programs.

Certification

Doctors cannot “prescribe” cannabinoid-based products unless they are in the form of one of the four FDA-approved pharmaceuticals. Instead, a health care provider “certifies” you to legally obtain and use medical cannabis. In some states, this may be called getting authorization or a recommendation.

The person providing certification is usually a physician (M.D. or D.O.), who confirms that you have a qualifying condition—a health problem with symptoms that could, hypothetically, be alleviated by cannabis. You’ll probably need it in writing, but some states allow oral consent.

Other health care professionals who can certify in certain states include physician assistants, nurse practitioners, registered nurses, naturopaths, dentists, podiatrists, and nurse midwives. Some states also require a registered pharmacist to be at dispensaries to advise people on the appropriate cannabis preparation and delivery method for their qualifying conditions. You don’t necessarily have to get certified by your usual doctor. In fact, most primary care providers in the United States don’t offer this service. But you can also find physicians who specialize in providing access to medical cannabis. You may see them referred to as “marijuana doctors” or “medical marijuana clinics.”

Registration

States require you to be on an official list, or registry, as a certified medical cannabis user. You may be required to obtain a physical card. Or you may need to be added to a database that medical cannabis providers can check. You will probably pay a fee for registration, typically good for one year.

Caregiver access

Medical cannabis laws allow you to designate a primary caregiver. This person is an adult who acts as an intermediary to buy, deliver, and/or administer medical cannabis to certified patients. A caregiver can also grow the cannabis, or help the patient to do it. It can be a family member or friend, but is often a home health care provider or other medical professional.

Where you buy it

Some states allow privately run, for-profit cannabis dispensaries— brick-and-mortar facilities where a certified patient or caretaker can enter and buy products. You generally need to prove that you are certified to enter.

In other states, only nonprofit dispensaries are permitted. Or the state may allow people to obtain medical cannabis from nonprofit “collectives” in which multiple patients band together to produce and provide cannabis to themselves.

Some states allow patients to cultivate a limited number of cannabis plants for medical use.

State laws vary on how much cannabis you can possess at any given time. They may specify either actual ounces of products, an amount to last a certain period (often one month), or a limited number of living plants in cultivation.

Hemp-based products

You do not need to obtain certification to buy and use legally available hemp-based products containing CBD. But always keep in mind that these products are not (yet) regulated for purity and potency. In contrast, most states require that medical cannabis products sold in dispensaries undergo testing.

Medical Marijuana: Facts about cannabis, THC, and CBD - Harvard Health (2024)

FAQs

What are the facts about medical marijuana? ›

There is moderate evidence that medical marijuana may help disturbed sleep associated with sleep apnea, fibromyalgia, chronic pain, and MS. Nausea and Vomiting? There are FDA-approved cannabinoid-based prescription drugs that can help with side-effects from chemotherapy when other medications don't.

What are the facts about CBD and THC? ›

CBD, unlike its psychoactive sibling THC, doesn't possess the properties that get you “high.” Unlike THC, which binds to your CB1 and CB2 nerve receptors to create different heady and bodily sensations, CBD is binding free.

What are the positive statistics about medical marijuana? ›

Statistics About Medical Marijuana Use

In 2018, 67% of doctors were in favor of using marijuana for medical purposes. And 85% of American adults approve of medical marijuana use. Marijuana can relieve symptoms associated with HIV/AIDS, cancer, Alzheimer's disease, Crohn's disease, epilepsy, and glaucoma.

What are the medically proven benefits of marijuana? ›

Benefits of Medical Marijuana

Drugs based on two lab-made forms of THC are FDA-approved for this purpose. Modestly reduce pain in people with conditions such as nerve damage, cancer, multiple sclerosis, and rheumatoid arthritis. Reduce muscle spasms in people with multiple sclerosis.

Does CBD oil really do anything for you? ›

CBD oil may help ease symptoms of anxiety, neurological disorders, heart health issues, and certain types of pain, among other health conditions. That said, while some study findings are available, more research is necessary to draw conclusions. Some studies are still ongoing.

What are the cons of CBD and THC? ›

THC and CBD may also have an effect on some health conditions and can interact with certain medications, so you should always use caution before taking these products. These substances might impact how medications are metabolized by your body. They can also heighten feelings of anxiety in some cases.

What does CBD and THC do for your health? ›

People take CBD and THC in hopes of relieving a wide variety of physical and mental health symptoms. While more studies are needed to understand it, some research suggests that CBD may help conditions such as: Anxiety. Inflammation.

Is THC oil bad for you? ›

Vaping THC oil can harm the lungs and has been associated with serious lung injuries and deaths. It also carries an increased risk for cognitive impairments, dependence, and psychiatric symptoms. The CDC and FDA recommend avoiding all e-cigarette and vaping products, especially those containing THC oil.

What medical illnesses does marijuana cure if any? ›

Older adults are using medical marijuana for dozens of other health concerns, including migraines, fibromyalgia, symptoms of Alzheimer's disease and dementia, Parkinson's disease, Crohn's disease and glaucoma. Some show promise. Medical marijuana reduced the frequency and intensity of migraines in one study.

What is the success rate of medical marijuana? ›

The response rate was 94%. Mean and median ages were 49.3 and 51 years respectively. Ninety-seven per cent of respondents used cannabis primarily for chronic pain. Average pain improvement on a 0–10 pain scale was 5.0 (from 7.8 to 2.8), which translates to a 64% relative decrease in average pain.

What are the arguments in favor of medical marijuana? ›

It's safer: Marijuana is safer than some other medications prescribed to treat pain. For example, some people may use it instead of opioids for pain management. Opioids are highly addictive and are typically not recommended for long-term use in treating chronic pain.

What are the cons of marijuana? ›

Long-term marijuana use has been linked to mental illness in some people, such as:
  • temporary hallucinations.
  • temporary paranoia.
  • worsening symptoms in patients with schizophrenia—a severe mental disorder with symptoms such as hallucinations, paranoia, and disorganized thinking.
Dec 24, 2019

What are the benefits of marijuana leaves to the body? ›

Raw cannabis leaves, stems, stalks, and seeds can provide the body with almost all of the essential nutrients including carbohydrates, protein, fat, water, vitamins, minerals, trace amounts of calcium, sodium, potassium, and omega-3 fatty acids.

How does CBD work in the body? ›

CBD, and CBD oil, works by interacting with numerous receptors in your body. CBD targets receptors in the brain and other major biological systems. Cannabidiol enhances how the body uses already existing cannabinoids, thus optimising certain bodily processes and functions.

What does marijuana do to your brain? ›

Studies note that early marijuana use can interrupt normal development of gray matter, a type of brain tissue that helps control mental functions, increasing schizophrenia risks. Early exposure to marijuana is also linked to changes in areas of the brain that are often connected with psychosis.

How does marijuana affect someone's driving ability? ›

According to studies, marijuana can slow your reaction time, impair judgment of distance, and decrease coordination, which are essential when you're behind the wheel of a vehicle. In recent years, drug-impaired driving has become a major highway safety issue.

What do we know about medical marijuana aarp? ›

As legal use spreads — medical marijuana is allowed in 38 states and three U.S. territories, while adult recreational use is legal in 24 states (up from 33 states and 11, respectively, in 2019) — the number of adults 50 and older experimenting with cannabis is growing fast: Sixteen million Americans age 50-plus tried ...

Which of the following statements about marijuana use is true? ›

The statement about marijuana that is true is: (c) Long-term use is associated with memory problems. Long-term use of marijuana has been linked to memory problems. Research has shown that regular and heavy use of marijuana can have negative effects on memory, learning, and cognitive function over time.

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