1/2: Cannabis and brain health 

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Miss the class?  Want to hear more?  Listen to Bridget Wright's lesson on cannabis and brain health.  

Cannabis:  A  guide to Cannabis and the effect on brain health

This week, we embark on a controversial and somewhat taboo topic, the use of cannabis and its effect in the brain.   We will look at the history of cannabis, an overview of the components and a look at how it works within the brain.  We will then describe the different ways that cannabis is consumed, the labeling of products and the research on cannabis.  Finally, we will discuss things to consider if you are using or are considering using this product.  We are not advocating the use of cannabis; instead, we mean to educate you so that you can make the right decision.  

A short history on cannabis

(Blaszczak-Boxe, 2014) 

Cannabis has been around for thousands of years.  It was widely used for medicine and spiritual purposes.  It was used by the Vikings and medieval Germans for relieving pain during childbirth and toothaches.  It was not always considered an evil drug; in fact, it has been legal in many regions of the world for most of its history.

Cannabis is believed to have evolved in Central Asia and goes back as far as 12,000 years.  It is one of humanity’s oldest cultivated crops.   Both hemp and psychoactive marijuana were widely used in ancient China, with the medicinal use dating back to 4,000 B.C.  However, it did not arrive in the United States until the beginning of the 20th century, arriving with immigrants fleeing the country during the Mexican Revolution. 

Early prejudices against marijuana may have been related to racist fears of smokers.  Mexicans were blamed for smoking marijuana, property crimes, seducing children and engaging in murderous sprees. 

In 1930, the Federal Bureau of Narcotics began to make marijuana illegal in all states, and by 1937 the Marijuana Tax Act put cannabis under regulation of the Drug Enforcement Agency.  It is still considered a Schedule I controlled substance, considered to be a high risk for abuse and dependency. 

Overview of Cannabis 

(Vallejo, 2019)(Holland, 2019) (Pearlson, 2020)(Savage, 2022)

Cannabis is a plant which can produce physical and psychoactive effects when consumed.  The plant has hundreds of compounds called “cannabinoids”.  The most known cannabinoid is tetrahydrocannabinol, or “THC”.  This is an intoxicating compound which provides psychoactive reactions.  The other cannabinoid is cannabidiol or “CBD” which is non-intoxicating and considered to be medicinal. 

Cannabis products all come from three subspecies of cannabis plants:

Although cannabis is illegal in some states, CBD is federally legal in all 50 states.

Cannabis contains over 400 compounds.  Besides THC and CBD, other significant compounds include:

There are specialized products which have been designed to combine different compounds into one product.  One of these, Nabiximols, has shown promise in research.  It is marketed as Sativex and is a THC plus CBD spray which has been approved for treatment of painful spasticity and neuropathic pain in multiple sclerosis.  It works by interacting with the cannabinoid receptors which regulate various bodily functions such as pain sensation, mood and immune response.  It is one of the few cannabis-based medications that have undergone rigorous trials to establish its efficacy and safety.

Dronabinol is another of these products.  It is the synthetic form of THC and is used to treat nausea and vomiting caused by chemotherapy, as well as to increase appetite in patients with AIDS and other conditions. Dronabinol is a Schedule II controlled substance and is only available by prescription in the United States.

Cannabis in the brain 

(Brenner, 2018)(Vallejo, 2019)

Cannabis works in the brain through the interaction of the active compounds (such as THC and CBD) with the endocannabinoid system, a network of receptors throughout the brain and body.  The receptors include the CB1 and CB2 receptors, with CB1 prominent in the brain.  These receptors are involved in functions such as mood, memory, appetite, and pain sensation.

The way that these compounds interact varies depending on the compound and the way that the cannabis is consumed.

THC binds to CB1 receptors in the brain associated with memory, cognition, motor coordination, emotions, and perception.  This binding changes the normal neurotransmitter function, and leads to psychoactive effects such as euphoria, altered perception and changes in cognitive functioning.

CBD on the other hand does not bind directly to CB1 or CB2 receptors.  Instead, it modulates the activity of receptors and influences the level of endocannabinoids.  It allows for potential relief of anxiety without the psychoactive effects of THC.


Video:  Use a human cadaver to learn more about the effects of cannabis on the body.  (Includes a short paid promotion.)  Really useful video!

Consuming marijuana and the effects of cannabis

 (How Marijuana is Consumed, 2016)

There are different ways of consuming cannabis.  They include inhalation (smoking or vaping), oral (edibles), or topical (applied to the skin).  These different methods use different delivery pathways and will impact the timing of the effects.  

• Inhalation:  This is the fastest method of delivery.  When inhaled, most cannabinoids enter the body through the lungs where they are passed into the blood stream.  The effect is almost immediate and lasts a few hours.  This creates rapid onset but may also result in a more intense psychoactive effect. 

• Oral:  Cannabis can also be consumed using edibles such as small gummy candies.  Edibles take longer to produce effects, as the compounds are absorbed through the digestive system and metabolized in the liver.  The process can take 30 minutes to 2 hours to take effect, and the effects can last longer than smoking.  This type of use carries a risk of overconsumption, as users may consume more before feeling any effects.     

• Topical:  Cannabis-infused creams and ointments can also be applied to the skin in the form of lotions, salves, bath salts and oils where they penetrate the skin and work to reduce pain and inflammation.  This method works well on localized pain (like arthritis) and is non-psychoactive.   

Understanding the labeling of Cannabis 

(Savage, 2022)

When faced with the task of finding the right product for your needs, it can be very confusing.  Here are some things that you would consider if you are interested in purchasing cannabis.

• Product name:  This will indicate the strain of cannabis which may be sativa, indica or hybrid.

• Type:  The form of this cannabis product (flower, extract, edible)

• Weight:  The quantity of the product

• Potency analysis:  Shows the percentage of each of the compounds (or cannabinoid) contains.  Although there are many cannabinoids, the three to focus on are THC, CBD and THCA.  THCA is an inactive cannabinoid which turns into THC when heated.  

• Dosing:  The product should state the intended amount for one dose.

• Terpene analysis:  Terpenes are naturally occurring compounds that determine the color, aroma, and taste of a cannabis strain.  Although not intoxicating on their own, they help produce some therapeutic effects like pain relief.  Experienced consumers use terpene analysis to determine the flavors, aromas, and effects they want from their product.  But this is not necessary for newcomers.

Research on Cannabis  

(National Academies of Sciences, 2017)

Cannabis has been studied and reported by a variety of entities, including peer-reviewed journals, medical textbooks, health organizations like WHO and NIH, government reports and universities.  The research has identified the various compounds in cannabis and how these compounds interact with the body’s endocannabinoid system.  They strive to find ways that cannabis can be therapeutic in several ways such as chronic pain, epilepsy, multiple sclerosis and mental health disorders.

Research is also underway looking at the effect of cannabis on brain function, such as the impact on cognition, memory, and motor skills.  It can also be used to provide insights into patterns of use including potential health risks and benefits, as well as side effects.  

Finally, research into cannabis will often look at legal and social implications, cannabis cultivation, development of medications based on cannabis, and the economic impact.  

A publication was released in 2019 which was written by the Committee on the Heath Effects of Marijuana. This committee detailed what research has found about the effects of cannabis in a treating several conditions.  It includes research on other health effects, such as cardiometabolic risk, respiratory disease, immunity, psychosocial, prenatal, and more.  Finally, it goes on to present the challenges of research as well as recommendations for future research.  You can read this report by clicking here.  Here are some of the highlights of the publication. Note that the product tested in this analysis is indicated in parentheses and includes cannabis, cannabinoids, nabiximols, THC, CBD and more.  

There is conclusive or substantial evidence that cannabis or cannabinoids are effective:

• For the treatment of chronic pain in adults (cannabis)

• As antiemetics in the treatment of chemotherapy-induced nausea and vomiting (oral cannabinoids)

• For improving patient-reported multiple sclerosis spasticity symptoms (oral cannabinoids)


There is moderate evidence that cannabis or cannabinoids are effective for:

• Improving short-term sleep outcomes in individuals with sleep disturbance associated with obstructive sleep apnea syndrome, fibromyalgia, chronic pain, and multiple sclerosis (cannabinoids, primarily nabiximols) 


There is limited evidence that cannabis or cannabinoids are effective for:

• Increasing appetite and decreasing weight loss associated with HIV/AIDS (cannabis and oral cannabinoids)

• Improving clinician-measured multiple sclerosis spasticity symptoms (oral cannabinoids)

• Improving symptoms of Tourette syndrome (THC capsules) 

• Improving anxiety symptoms, as assessed by a public speaking test, in individuals with social anxiety disorders (cannabidiol)

• Improving symptoms of posttraumatic stress disorder (nabilone; a single, small fair-quality trial)


There is limited evidence of a statistical association between cannabinoids and:

• Better outcomes (i.e., mortality, disability) after a traumatic brain injury or intracranial hemorrhage 


There is limited evidence that cannabis or cannabinoids are ineffective for:

• Improving symptoms associated with dementia (cannabinoids)

• Improving intraocular pressure associated with glaucoma (cannabinoids)

• Reducing depressive symptoms in individuals with chronic pain or multiple sclerosis (nabiximols, dronabinol, and nabilone)


There is no or insufficient evidence to support or refute the conclusion that cannabis or cannabinoids are an effective treatment for:

• Cancers, including glioma (cannabinoids)

• Cancer-associated anorexia cachexia syndrome and anorexia nervosa (cannabinoids)

• Symptoms of irritable bowel syndrome (dronabinol)

• Epilepsy (cannabinoids)

• Spasticity in patients with paralysis due to spinal cord injury (cannabinoids)

• Symptoms associated with amyotrophic lateral sclerosis (cannabinoids)

• Chorea and certain neuropsychiatric symptoms associated with Huntington’s disease (oral cannabinoids)

• Motor system symptoms associated with Parkinson’s disease or the levodopa-induced dyskinesia (cannabinoids)

• Dystonia (nabilone and dronabinol)

• Achieving abstinence in the use of addictive substances (cannabinoids)

• Mental health outcomes in individuals with schizophrenia or schizophreniform psychosis (cannabidiol)

This analysis demonstrates the lack of evidence surrounding the medicinal properties of cannabis.  There are very few uses that have shown conclusive benefits and many which are inconclusive or unable to confirm or deny.  Like any product, it is important to weigh the risks against the benefits before using.

Videos describing the use of cannabis for recreational and medicinal uses

Video:  Learn about a study on people using CBD for anxiety

Some of the negative effects of cannabis.  .  You will have to go directly to YouTube to view.

Video:  A lengthy (55 minutes) webinar on cannabis use.

Video:  Conditions from long-term use of cannabis

Video:  A 50 minute webinar on the use of cannabis for Alzheimer's

Video:  Cannabis may have negative mental effects to users, especially in the developing mind.  

Things to consider if you are a cannabis user or are considering using cannabis

(Murez, 2023)


It is not within the scope of this class to recommend or condemn the use of cannabis.  This choice is up to you.  However, this lesson has provided some insights.

CBD is the safest best:  CBD is legal in 50 states, does not provide intoxicating effects and has some documented uses for medical conditions like anxiety, chronic pain, nausea (from chemotherapy) and sleep.

THC is not fully understood:  Although research suggests that 6 – 7% of older adults use cannabis, the risks are unknown.  It is also associated with health risks unique to older adults. 

Health risks to older adults:  Cannabis use has been linked to dizziness and falls, panic attacks, heart palpitations, confusion, anxiety or worsening of underlying lung disease.   Researchers suggest that the physiological changes associated with aging make us more sensitive to psychoactive properties.  In addition, factors like dosing and interactions with other medications may produce unwanted side effects.  If you use cannabis, consult with your doctor to see if there are conflicts with your medicines.

Today’s cannabis is not the same as what you remember:  While you may have used cannabis in the past, present strains are stronger.  They may come with added ingredients.  The form of the product (tincture, edible, flower) will have different levels of compounds.  It is important to consume the least amount necessary to meet your needs. 

Discuss cannabis use with your doctor:  Cannabis is legal and should not be something that you need to hide from your doctor.  Instead, let them know that you are using it, especially if it is being used for a medical condition.  You might bring your product with you on your next visit so that the doctor can help determine if this is the best product for you. 

Summary

Although marijuana is widely used, and legal in California, it is not without risks.  Like any drug, it is important to weigh the benefits and the risks to determine if this is something for you.  There is a lot of research on the topic, and we should learn more as time goes on.  If this is something you would like to try, you might consider visiting a dispensary.  They have trained staff who can help you recommend a product which is right for you.

Works Cited

Blaszczak-Boxe, A. (2014, October 17). Marijuana's History: How One Plant Spread Through the World. Retrieved from livescience.com: https://www.livescience.com/48337-marijuana-history-how-cannabis-travelled-world.html

Brenner, G. H. (2018, January 21). Neuroimaging, Cannabis, and Brain Performance & Function. Retrieved from psychologytoday.com: https://www.psychologytoday.com/us/blog/experimentations/201801/neuroimaging-cannabis-and-brain-performance-function

Campbell, D. G. (2018, July). Effect of cannabis use in people with chronic non-cancer pain prescribed opioids: findings from a 4-year prospective cohort study. Retrieved from thelancet.com: https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(18)30110-5/fulltext

Craft, R. (2014, September 3). Estrogen increases cannabis sensitivity. Retrieved from eurekalert.org: https://www.eurekalert.org/pub_releases/2014-09/wsu-eic082814.php

Davis, K. (2018, August 1). Everything you need to know about marijuana (cannabis). Retrieved from medicalnewstoday.com: https://www.medicalnewstoday.com/articles/246392.php

Drug Alert: Marijuana Edibles. (2016, March). Retrieved from justthinktwice.gov: https://www.justthinktwice.gov/article/drug-alert-marijuana-edibles

FDA approves first drug comprised of an active ingredient derived from marijuana to treat rare, severe forms of epilepsy. (2018, June 26). Retrieved from fda.gov: https://www.fda.gov/news-events/press-announcements/fda-approves-first-drug-comprised-active-ingredient-derived-marijuana-treat-rare-severe-forms

Gurney, J. e. (2015, November 11). Cannabis exposure and risk of testicular cancer: a systematic review and meta-analysis. Retrieved from ncbi.nlm.nih.gov: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4642772/

Holland, K. (2019, April 9). Sativa vs. Indica: What to Expect Across Cannabis Types and Strains. Retrieved from healthline.com: https://www.healthline.com/health/sativa-vs-indica

How Marijuana is Consumed. (2016, April 2). Retrieved from drugpolicy.org: http://www.drugpolicy.org/drug-facts/10-facts-about-marijuana/how-marijuana-consumed

Is marijuana addictive? (2019, July). Retrieved from drugabuse.gov: https://www.drugabuse.gov/publications/research-reports/marijuana/marijuana-addictive

McGrath, J. e. (2010, May). Association Between Cannabis Use and Psychosis-Related Outcomes Using Sibling Pair Analysis in a Cohort of Young Adults. Retrieved from jamanetwork.com: https://jamanetwork.com/journals/jamapsychiatry/fullarticle/210748

Murez, C. (2023, January 16). Marijuana-Linked ER Visits by Seniors Are Rising. Retrieved from USNews: https://www.usnews.com/news/health-news/articles/2023-01-16/marijuana-linked-er-visits-by-seniors-are-rising

National Academies of Sciences, E. a. (2017). The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. Washington, DC: The National Academies Press. doi:https://doi.org/10.17226/24625

Oleson, E. &. (2012, August 2). A Brain on Cannabinoids: The Role of Dopamine Release in Reward Seeking. Retrieved from ncbi.nlm.nih.gov: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3405830/

Pappas, S. (2016, November 22). 25 Odd Facts About Marijuana. Retrieved from livescience.com: https://www.livescience.com/56600-odd-facts-marijuana.html

Pearlson, G. (2020). Currently available legal cannabinoid drugs and their indications. In Weed Science. New York: Academic Press. Retrieved from https://www.sciencedirect.com/topics/neuroscience/nabiximols

Rettner, R. (2016, March 30). Marijuana Addiction Linked to Genetics. Retrieved from https://www.livescience.com/54234-marijuana-dependence-genetics.htmllivescience.com

Savage, H. (2022, December 27). How to read a cannabis product label. Retrieved from inquirer.com: https://www.inquirer.com/philly-tips/cannabis-product-label-meaning-percentages.html

Vallejo, N. (2019, June). Cannabis (Marijuana). MOJ Addiction Medication and Therapy. Retrieved from https://medcraveonline.com/MOJAMT/MOJAMT-06-00149.pdf

Yanes, J. e. (2018, January 17). Neuroimaging meta-analysis of cannabis use studies reveals convergent functional alterations in brain regions supporting cognitive control and reward processing. Retrieved from ncbi.nlm.nih.gov: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5858977/