Medical Marijuana: What Are the Effects and Side Effects?
Physical Health
Medical marijuana has become increasingly popular since it was first legalized in California in 1996. Since then, medical marijuana use has grown, with an estimated 3.6 million Americans using medical marijuana in 2020. With its growing popularity, you may be wondering, “What are the effects and side effects of medical marijuana?”
Continue reading to learn more about what medical marijuana is used for, how it works, its effect on your body, and the potential side effects of its use.
What Is Medical Marijuana?
Before we dive into the risks and benefits, we should understand what medical marijuana is. Marijuana comes from the cannabis plant, also known by its scientific name Cannabis sativa. The cannabis plant has been used in Africa and Asia as a medicinal plant for thousands of years.
Although cannabis and marijuana are often used interchangeably, they aren’t exactly the same thing. While cannabis refers to any product that comes from the Cannabis sativa plant, marijuana refers specifically to parts of the plant that contain the compound tetrahydrocannabinol (THC). THC is a compound in the cannabis plant that’s mostly responsible for the mind-altering effects of marijuana. In other words, THC is the compound in marijuana that gets you high.
Medical marijuana is marijuana used to help ease symptoms of a medical condition. In the United States (US) and Canada, medical marijuana isn’t approved to treat any medical conditions. However, pharmaceutical companies have developed several prescription drugs made from purified or synthetic compounds from the cannabis plant. A purified form of cannabidiol (CBD) called Epidiolex is approved to treat seizures in several countries. Dronabinol (Marinol) is a drug that contains a synthetic form of THC that’s used to treat nausea and vomiting due to chemotherapy and HIV-related weight loss. Nabilone (Cesamet, Canemes) is a synthetic THC that’s used to treat cancer-related nausea and vomiting. Nabiximols (Sativex) is a purified cannabis extract with equal parts THC and CBD that’s approved in Canada to treat pain related to cancer and multiple sclerosis.
What Is Medical Marijuana Used For?
Medical marijuana can be used to treat a wide variety of medical conditions. Health Canada lists the following potential therapeutic uses for medical marijuana:
- Palliative care
- Chemotherapy-induced nausea and vomiting
- Wasting disease and loss of appetite related to AIDS, cancer, or anorexia nervosa
- Multiple sclerosis
- Epilepsy
- Pain
- Arthritis
- Movement disorders
- Glaucoma
- Parkinson’s disease
- Anxiety and depression
- Sleep disorders
- Post-traumatic stress disorder (PTSD)
- Alcohol and opioid withdrawal syndrome
- Inflammatory skin disorders
- Digestive system disorders
In the US, pain control is the most common reason people use medical marijuana. Research is ongoing to learn more about how marijuana can be used to treat different medical conditions.
Is Medical Marijuana Legal?
The answer to the question, “Is medical marijuana legal?” depends on where you live.
In the US, marijuana is classified as a Schedule I controlled substance — a drug with no accepted medical use and high potential for abuse. This means that physicians can’t prescribe medical marijuana. In states that have approved medical marijuana, physicians can certify its use for some patients. In Canada, physicians can authorize the use of marijuana for medical purposes. Additionally, marijuana is fully legalized for recreational use locally in several US states and provinces in Canada.
Talk to your physician or attorney about the laws and regulations regarding medical marijuana where you live.
How Does Medical Marijuana Work?
Marijuana’s effect is due to a group of substances found in the cannabis plant called cannabinoids. The two main cannabinoids are THC and CBD.
As previously discussed, THC is the cannabinoid primarily responsible for the euphoric high you get after consuming marijuana. CBD is another cannabinoid that can affect your body without making you high. Although THC and CBD are the main cannabinoids, there are more than 100 cannabinoids found in the cannabis plant.
The cannabinoids in marijuana interact with the endocannabinoid system in your body. The endocannabinoid system is a network of chemicals and chemical receptors naturally found in your body. This system helps regulate body functions such as:
- Learning and memory
- Emotions
- Sleep
- Temperature control
- Pain
- Inflammation
- Immune system
- Appetite
By interacting with the endocannabinoid system, the cannabinoids in marijuana can affect several different body functions.
How Do You Use Medical Marijuana?
According to Health Canada, there isn’t a scientifically defined dose of marijuana for any medical condition. Most people who use marijuana use less than 3 grams of dried marijuana.
Talk to your physician to find the best dose for you. If you’re taking medical marijuana for the first time, it’s best to start with a very low dose, such as 1 mg of THC. You can increase or decrease your dose based on how it makes you feel and what side effects you experience.
You can consume medical marijuana in several ways, including:
- Eating baked goods or candy (such as gummies) made with marijuana
- Drinking tea brewed with marijuana
- Taking pills (capsules or tablets) with marijuana extract
- Applying creams or lotions with marijuana extract to your skin
- Inhaling smoke from burning dried marijuana leaves
- Inhaling vapor from resin made from marijuana leaves
The different methods of taking medical marijuana will have different onset (how long it takes to feel the effects) and duration (how long you feel the effects). When you inhale marijuana, you’ll feel the effects within a few minutes, with a peak effect about 30 minutes later. The effects usually last about 2 to 4 hours but can be longer. When you eat or drink marijuana, the onset and duration are usually longer compared to inhaling it. You can start to feel the effects from 30 minutes to 4 hours after you take it. The effect of eating or drinking marijuana can last for up to 8 hours for some people.
Work with your physician to find the best medical marijuana product and dose that improves your symptoms with the fewest side effects.
What Are the Effects of Medical Marijuana?
As marijuana interacts with the endocannabinoid system around your body, it affects several different body systems. We’ll discuss the short-term effects of marijuana on each of your body systems below.
Central Nervous System
Your central nervous system (CNS) is made up of your brain and spinal cord. The CNS controls your thinking, your five senses, speech, and movement. CNS effects of marijuana include:
- Euphoria (the feeling of being “high”)
- Increased sensory perception
- Distorted sense of time
- Drowsiness or sleepiness
- Memory impairment
- Lack of coordination
- Pain relief
- Increased appetite
Cardiovascular System
Your cardiovascular system is made up of your heart and blood vessels. This system helps pump blood and oxygen around your body. Marijuana's effects on the cardiovascular system include:
- Increased heart rate
- Red eyes
- Dizziness when you stand up (postural hypotension)
Respiratory System
Your respiratory system consists of your lungs, airways, mouth, and nose. Its main function is to breathe in oxygen and eliminate carbon dioxide. When you smoke marijuana, it can cause coughing, wheezing, and mucus production. THC can cause your airways to temporarily relax.
Gastrointestinal System
Your gastrointestinal (GI) system helps you eat and digest food. Marijuana affects your GI system in the following ways:
- Slowed stomach emptying
- Increased appetite
- Dry mouth
Musculoskeletal System
Your musculoskeletal system is made of your muscles and bones to help you move. Marijuana may help improve chronic (long-term) joint pain and decrease muscle spasms.
What Are the Risks of Medical Marijuana?
As with most medical treatments, there are risks associated with the use of medical marijuana. We’ll discuss the short and long-term side effects, possible drug interactions, and other risks of using medical marijuana.
Short-Term Side Effects of Marijuana
Short-term side effects are negative effects you feel right after using medical marijuana, including:
- Dizziness
- Drowsiness
- Lightheadedness
- Headache
- Mood changes
- Difficulty concentrating
- Feeling disoriented or confused
- Anxiety or paranoia
- Hallucinations (seeing or hearing things that aren’t there)
- Loss of body control
- Slow reaction time
- Dry mouth
- Coughing
- Allergic reactions such as hives
- Nausea and vomiting
- Increased heart rate
- Low blood pressure
Although high doses of marijuana can cause unpleasant side effects, no deaths have been recorded due to marijuana intoxication.
Long-Term Side Effects of Marijuana
Long-term side effects are the side effects that occur months or years after using marijuana. Researchers are still learning about the long-term effects of marijuana, which may include:
- Increased risk of developing or worsening serious mood disorders such as schizophrenia, anxiety, depression, or bipolar disorder
- Increased risk of respiratory infections in people who smoke marijuana
- Behavioral and developmental problems born to mothers who used cannabis while pregnant
- Decreased ability to think and make decisions, especially in adolescents who use marijuana
- Tolerance (decreased effects of marijuana over time)
- Cannabis hyperemesis syndrome (severe vomiting)
- Gum disease
- Increased risk of heart attack and stroke
- Decreased fertility in men and women
- Increased risk of car accidents and injury
- Increased risk of falls in people over 65
- Increased risk of some cancers, such as testicular cancer, bladder cancer, and lung cancer
Marijuana Drug Interactions
Marijuana can affect the way other medications work due to its side effects and the way your body processes it. That’s why it’s important to talk to your physician about all prescription and over-the-counter (OTC) medications and vitamins and supplements you’re taking when discussing adding medical marijuana to your treatment plan. Additionally, you should always tell your physician that you’re using medical marijuana before you start taking any new medication.
The intoxication and drowsiness marijuana causes can increase the sedative (drowsy) effect of other medications, such as:
- Alcohol
- Sleeping medications
- Anxiety medications
- Some anti-seizure medications
- Some cold and allergy medications
- Opioid pain medications
People who use marijuana while taking selective serotonin reuptake inhibitors (a type of antidepressant) may have an increased risk of mania (an abnormally elevated mood and energy level).
Marijuana may change the way your body processes other medications, resulting in a decreased effect of some medications, including blood thinners, supplements, and antiviral drugs used to treat HIV.
This is not an exhaustive list of drug interactions with marijuana. Researchers are still learning about drug interactions with marijuana. Talk to your physician about your risk of drug interactions while you’re using medical marijuana.
Accidental Marijuana Exposure
Edibles — such as baked goods, candy, chocolate, and gummies — are a popular way to take medical marijuana. Many commercially available marijuana edibles are packaged to look like treats that young children and pets would be interested in. This can lead to accidental consumption of marijuana edibles that can lead to emergency room visits.
Is Marijuana Addictive?
Yes, marijuana can be addictive. It’s estimated that about 1 in 10 people who use marijuana will develop cannabis use disorder (addiction). Adolescents are more likely to develop cannabis use disorder compared to adults. Symptoms of cannabis use disorder include:
- Craving marijuana
- Lack of control of marijuana use
- Negative effects on your relationships, health, and professional responsibilities
If you have cannabis use disorder and stop using marijuana, you may experience withdrawal-like symptoms, such as:
- Anger or aggression
- Irritability
- Anxiety
- Nightmares
- Difficulty sleeping
- Craving marijuana
- Headaches
- Restlessness
- Decreased appetite
Talk to Your Physician About Medical Marijuana
If you’re interested in adding medical marijuana to your treatment plan, talk to your physician about the benefits and risks. Clinical trials are currently ongoing to discover if medical marijuana can be a safe and effective treatment option for several different health conditions. If you live in a region where you don’t need a physician’s recommendation to purchase marijuana, it’s still a good idea to discuss adding marijuana to your treatment plan with your physician before doing so.
