When people talk about medical marijuana, they're referring to any part of a marijuana plant used to alleviate any health problem. People don't use this to get high, but rather to ease their medical symptoms.
When cannabis is legally sold as medicine, it is typically no different from the type used for pleasure. However, new strains of medical marijuana have been specially developed with fewer chemicals that cause euphoria and more chemicals thought to provide other health benefits.
In the following slides, you will learn information about
- the chemicals that make up medical marijuana,
- how cannabis affects the brain,
- side effects that accompany the drug,
- what manufactured drugs have been developed based on marijuana's chemical properties,
- the laws for states that have legalized medical marijuana, and
- the use of medical marijuana to treat children.
There are more than 80 chemical compounds in cannabis known as cannabinoids. These chemicals are responsible for the plant's psychoactive effects. Of these, the two most researched compounds are THC (tetrahydrocannabinol) and CBD (cannabidiol), which were both discovered in the early 1960s. THC is considered the main psychoactive chemical in marijuana, but CBD has recently raised interest due to its potential to treat illnesses like seizures.
THC and Medical Cannabis
As the main psychoactive ingredient in marijuana, THC has also been the plant's most frequently researched chemical. THC is believed to affect the human body in several ways, influencing body temperature, pulse rate, perception of time, anxiety, sedation, analgesia (reduction of the perception of pain), short-term memory, and spatial awareness.
THC is also the chemical that creates the euphoric high typically sought by recreational cannabis users.
CBD and Medical Cannabis
CBD works very differently from THC. Compared to THC, it takes about 100 times more CBD to have any impact on cannabinoid receptors, the sites in the body that interact with cannabinoids. Unlike THC, CBD does not cause either intoxication or euphoria. In some ways, CBD seems to have the opposite effect of THC. For instance, while THC tends to increase anxiety, CBD appears to reduce anxiety.
Marijuana's impact on the brain is complex and varies from person to person. How quickly cannabis works depends on how it is consumed. When smoked, the effects are felt almost immediately because THC goes quickly into your bloodstream via your lungs. This causes brain cells to release dopamine, creating the sensation of euphoria. Eating cannabis causes its effects to be felt more slowly, sometimes taking as long as an hour or more.
THC, CBD and other cannabinoids interact with the human brain at sites called cannabinoid receptors. Cannabinoid receptors are found on human cells and are involved with various process that help maintain consistency within the body despite changes in the body's environment, a concept known as homeostasis. The main cannabinoid receptors are referred to as CB1 and CB2.
CB1 receptors seem to influence cognition, memory, motor movements, and pain perception. Most CB1 receptors exist in the brain, but some can be found in the nerves of the liver, thyroid, uterus, bones, and testicular tissue.
Unlike CB1 receptors, CB2 receptors are mostly found in immune cells, the spleen, and the gastrointestinal system.
CB2 receptors are also found in the brain, but to a lesser extent. CB2 receptors play a role in human reproduction, too, from embryonic development to sperm survival. Cannabinoids act on CB2 receptors to reduce the gastrointestinal inflammation found in conditions like inflammatory bowel disease (IBD).
Cannabinoids and Endocannabinoids
Your body makes its own cannabinoids, which are called endocannabinoids. Endocannabinoids perform a wide range of activities related to maintaining homeostasis, from nursing to growth to responding to injuries. The cannabinoids in marijuana interfere with the body's natural regulation of various chemicals, including dopamine. Researchers suspect that cannabinoids allow more of these chemicals to be released than would normally be the case.
Various lines of research into the health effects of marijuana are ongoing. However, research into medical cannabis has been hampered since the 1930s by the drug's illegality, a situation only now beginning to change for would-be researchers. This means that while many promising benefits of medical cannabis are being researched, in many cases further and repeated studies will be necessary before these uses can be approved by doctors.
Medical Uses of THC: Increased Appetite
One of the most well-established medical uses for cannabis is in increasing appetite for AIDS and cancer patients, those with wasting diseases, and other patients who might benefit from an increase in appetite.
The synthetic THC pill Marinol was approved by the U.S. Food and Drug Administration in 1985 for just such a purpose. Marinol has been shown to stimulate the appetite and reduce nausea and vomiting.
Other Medical Uses of THC
Beyond its ability to stimulate appetite, THC may be medically useful in several other ways. Here are a few of the potential medical benefits of THC:
- Pain reduction
- Inflammation reduction
- Improving problems in muscle control
Medical Uses of CBD
CBD, a non-psychoactive cannabinoid found in cannabis, has garnered a lot of media attention for its use in young children to relieve the symptoms of serious seizures. Many more medical uses have been suggested for CBD, including
- neuroprotection from conditions such as Alzheimer's disease, stroke, multiple sclerosis (MS), and Parkinson's disease,
- pain reduction for conditions like cancer, MS, and rheumatoid arthritis,
- anti-tumor effects,
- anti-psychotic effects for schizophrenia, Parkinson's disease, and post-traumatic stress disorder,
- anti-anxiety effects, and
- treatment for drug addiction, particularly morphine and heroin addiction.
Along with its many potential health benefits, medical marijuana also causes several potential side effects. In the short term, medical marijuana can disrupt short-term memory, disrupt the ability to make decisions, and alter mood, making a patient feel happy, relaxed, sleepy, or anxious.
In large doses, some people using medical marijuana will experience hallucinations, paranoia, and delusions.
Along with its short-term side effects, regular users of marijuana may also experience side effects over the long term. These side effects include respiratory problems such as lung infections and a daily cough for those who take medical marijuana through smoking; depression, anxiety, lack of motivation, suicidal thoughts, and health problems in babies if cannabis is used during pregnancy.
Is Marijuana Addictive?
Whether or not marijuana is addictive has been hotly contested for a long time. There is no agreed-upon definition of marijuana addiction, but the World Health Organization has established criteria for cannabis dependence. To be considered marijuana-dependent by the WHO, a person must be an active user and fit three or more of the following criteria. The user:
- has a strong desire or compulsion to take cannabis;
- has trouble controlling when they take cannabis, when they do not, and how much they take;
- experiences withdrawal when reducing or stopping use of the drug, including either symptoms of withdrawal or use of a similar drug to achieve similar results;
- requires more marijuana to get the same results;
- neglects other pleasures and interests in order to either use, obtain, or recover from marijuana;
- continues to use cannabis even though it causes harm.
Risks of marijuana dependence are lower than dependence risks of other common drugs. The risk of cannabis dependence has been estimated at about 9%, as compared to 32% for nicotine, 23% for heroin, and 15% for alcohol. The risk of marijuana dependence climbs to 16%, however, when use begins in adolescence. A family history of addictive behavior also increases this risk.
In 1985, the FDA approved two similar drugs based on the marijuana cannabinoid THC: dronabinol (Marinol) and nabilone (Cesamet). Both are prescribed to increase appetite, decrease nausea and vomiting, and manage pain.
Dronabinol is actually an extract derived from natural cannabis resin. This means the THC found in dronabinol is no different from the THC found in natural cannabis. It also means that dronabinol carries with it the same mood and perceptual changes associated with the THC found in cannabis.
Unlike dronabinol, Nabilone does not come from a cannabis source. Nabilone is a synthetic cannabinoid that is structurally similar to THC, but it is not THC. As such it has more predictable results, eliminating or greatly reducing the euphoria THC may induce.
There are three ways marijuana can be used as medicine: by eating it, by breathing it in, or by rubbing it on the skin.
Ingesting Medical Cannabis
Edible cannabis can take many forms. It may be baked into a treat like a cookie or brownie, infused in a drink like soda, or prepared as a pill like the drugs described in the previous slide. When medical marijuana is made as a food or drink, it is sometimes referred to as an “edible.”
When ingested, the effects of medical marijuana are delayed. Typically the effects take about 30 to 60 minutes to initiate. These effects typically peak after two to three hours. Because the effects take much longer to begin and peak much later when medical marijuana is consumed, a patient cannot control the dosage as easily. For this reason, patients often consume more than they had intended. The effects also last much longer when medical marijuana is ingested, sometimes lasting as long as 10 hours.
Because it can be mixed into butter or oil, THC edibles can take many forms, including cookies, cupcakes, hard candy, chocolate, jerky, salads, and burgers.
Since these foods often resemble food without cannabinoids, medical users should be careful to keep them away from children, pets, and unsuspecting others.
Breathing Medical Cannabis
Perhaps the most common method of taking cannabis is to smoke it, either in a rolled paper cigarette (sometimes called a “joint,”), in a pipe, or through a water-filtering bong.
Smoking cannabis presents many of the same dangers as smoking cigarettes. Regular marijuana smokers may experience more frequent upper respiratory infections, excess mucus, and a daily cough. Marijuana smoke contains some of the same cancer-causing chemicals as tobacco smoke, though several studies have failed to demonstrate a higher risk of lung cancer in marijuana smokers.
Although marijuana smoke is often held much longer in the lungs than tobacco smoke (often for 10-15 seconds), this practice is not useful and could be harmful. One study found no difference between a study group that held marijuana smoke for 20 seconds, another that held smoke for 10 seconds, and a third group that did not hold the smoke in their lungs at all.
Another, more recent, form of breathing cannabis is through vaporizers. Vaporizing (“vaping”) marijuana has been shown in some studies to reduce potentially harmful tars and cause fewer respiratory symptoms than typical cannabis smoking. However another study showed that vaporizing marijuana created more harmful levels of toxic ammonia, which can bring on asthma and irritate lungs.
Applying Marijuana Topically
Probably the least common method of using medical marijuana is as a topical patch, salve, or ointment. Topical cannabis has certain advantages over other methods of use. It is released via the skin directly into the bloodstream, meaning the stomach does not break it down, making it more efficient. Using cannabis topically also eliminates the harm caused by inhalation.
In 1996, California voters passed the first laws in the nation to legalize medical marijuana. Since that time, all but eight states have passed laws legalizing some form of medical marijuana.
Laws vary greatly from state to state. Some states allow only CBD for use as a medical treatment. Others forbid smoking cannabis but allow it to be consumed in other ways. Some states have legalized both medical and recreational marijuana sales.
While the majority of U.S. states have removed at least some of the penalties and restrictions related to the sale and use of medical marijuana, the sale and distribution of marijuana remains a serious crime under federal law. According to the Office of National Drug Control Policy, the Department of Justice "is committed to enforcing the Controlled Substances Act consistent with" Congress' determination "that marijuana is a dangerous drug."
Children with hard-to-treat epilepsy may find relief from their seizures through medical marijuana, according to some studies. One strain of medical marijuana, "Charlotte's Web" makes it easier to treat kids without getting them high because the strain has high amounts of CBD but very low levels of THC.
The trend toward using medical marijuana in children is relatively recent, meaning few studies have been performed as to its effects. One study of 74 children ages 1-18 with intractable epilepsy found that 89% reported some seizure reduction following treatment using a CBD oil. Other positive benefits reported by these subjects included improved behavior and alertness, better communication, language improvements, improved motor skills, and better sleep.
Reported adverse effects included drowsiness, fatigue, stomach upset, and irritability.
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- Bob Berg / Getty Images
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- Therapeutic Advances in Psychopharmacology: "Cannabis, a Complex Plant: Different Compounds and Different Effects on Individuals."
- National Institute of Health: "The Biology and Potential Therapeutic Effects of Cannabidiol."
- British Journal of Pharmacology: "Cannabinoids and Intestinal Motility: Welcome to CB2 Receptors."
- Current Drug Targets - CNS & Neurological Disorders: "Cannabinoids."
- NORML: "Introduction to the Endocannabinoid System."
- Clinica Chimica Acta: "Endocannabinoids and Pregnancy."
- National Institute on Drug Abuse: "DrugFacts—Is Marijuana Medicine?
- Dialogues in Clinical Neuroscience: "Cannabinoids in Health and Disease."
- World Health Organization: "The Health and Social Effects of Nonmedical Cannabis Use."
- U.S. National Library of Medicine: "Dronabinol."
- DrugBank.ca.: "Nabilone."
- Partnership for Drug-Free Kids: "Researchers Develop Patch to Deliver Psychoactive Ingredient of Marijuana."
- Penn State: "Medical Marijuana: Scientific Mechanisms and Clinical Indications."
- Colorado Department of Public Health and Environment: "FAQs: Marijuana and Methods of Use."
- County of Los Angeles Public Health: "Marijuana Edibles Fact Sheet."
- Pharmacology, Biochemistry, and Behavior: "Breathhold Duration and Response to Marijuana Smoke."
- U.S. Office of National Drug Control Policy: "Marijuana Resource Center: State Laws Related to Marijuana."
- NORML: Medical Marijuana
- Seizure: "CBD-Enriched Medical Cannabis for Intractable Pediatric Epilepsy: The Current Israeli Experience."