A cannabis glossary

The interest in cannabis and cannabis derived products is growing. In the last 5 years more than 12000 cannabis-related research studies have been published*. It’s almost impossible to stay in touch with this enormous amount of information, even for scientists.

Many of these studies are covered by science communication outlets and published in open access scientific journals, so anyone who would like to can see the original results.

Unfortunately these results can be exaggerated, both in their interpretation and their clinical relevance. Sometimes, the results are completely misinterpreted too. Reading through scientific articles might sound very complicated, but getting the basic information can be easy for anyone interested.

A sticky point with any scientific article, and in fact any specialist publication, is the use of jargon. The use of acronyms and complicated words makes even a recipe for pasta sauce sound nuanced and esoteric. The reality is that jargon is helpful when authors want to be concise and precise, but not everyone understands it.

If you are interested in following research related to cannabis, getting familiar with some jargon will be essential to help you cut through the noise. To help with this, I thought it would be a good idea to put together a glossary of some terms you might encounter in scientific literature related to cannabis research.

Cannabinoids

A group of chemicals that interact with the body’s cannabinoid receptors. They can be broken down into two main categories: phytocannabinoids and endocannabinoids.

Cannabinoid receptors

Cannabinoids interact with proteins. A specific type of these proteins are called cannabinoid receptors. When cannabinoids interact with these receptors, they can lead to a range of biochemical changes in our body. There are two types of cannabinoid receptors (CB1 and CB2).¹ CB1 is found mainly in the central nervous system and CB2 is mainly found in the rest of the body (immune and gastrointestinal system), although there is mounting evidence that CB2 is expressed in the brain as well.²

Endocannabinoids

Compounds that our body creates to interact and activate various protein receptors within the body - hence the name endogenous (originate from within) cannabinoids.³ Just like so many other compounds we produce, endocannabinoids are involved in many functions: they regulate the function of multiple organs, and are important for pain and memory. Recently, scientists found that cannabinoids may be behind the runner's high, something previously attributed to endorphins (an endogenous opioid).⁴ The most well-studied endocannabinoids are 2-Arachidonoylglycerol (2-AG) and arachidonoylethanolamide (anandamide).

Endocannabinoid System

The endocannabinoid system is a unique communication system found throughout the brain and body.³ It consists of (1) the chemical signals (endocannabinoids), (2) proteins that interact with endocannabinoids and produce some biological effect (cannabinoid receptors), and (3) proteins (enzymes) which make and destroy the endocannabinoids. This system is involved in appetite control, pain perception, memory and even mood.

Phytocannabinoids

Phytocannabinoids, are plant-derived cannabinoids, most notably from the cannabis plant.⁵ The most widely known phytocannabinoids are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). They have been the main subject of research because they are the most prolific cannabinoid found in the cannabis plant.

More than 100 phytocannabinoids have been discovered in the various strains of the cannabis plant.⁶ Many of them interact strongly, not only with the body’s cannabinoid system, but other receptors in the body too. Some cannabinoids also interact with serotonin receptors which are well known for their role in the stress response and appetite control.

Carotenoids

Carotenoids are a group of chemical compounds that give cannabis flowers the different warm colours (red, orange and yellow). The name may sound familiar, and that’s because it comes from the Latin word carota, which means (who would have guessed it) carrot!

Flavonoids

Flavonoids are a group of plant-produced chemicals which, along with carotenoids, are responsible for the colour, and taste, in plants, fruits and vegetables. Although cannabinoids and terpenes are the centre of attention when discussing the cannabis-based products, flavonoids play an important role in the plant’s biology as well. These compounds account for approximatelly 10% of known cannabis compounds. Flavonoids are found in many plant species, but the cannabis plant produces some unique flavonoids! These compounds are known as ‘cannaflavins’. Cannaflavins, along with terpenes, offer distinct colour and taste to different cannabis strains.

Terpenes

They are responsible for the characteristic smell of pine! These chemicals are also found in cannabis and virtually every plant-based aromatic mixture. They give many fruits their distinctive smell. Cannabis plants contain more than 300 different terpenes. You might have heard of them as terpenoids, but these two terms have different meanings.

The main difference between terpenes and terpenoids is that terpenes are composed of the elements carbon and hydrogen (known as hydrocarbons), whereas terpenoids have additional elements like oxygen.⁷ Until recently, it was generally accepted that the only active compounds in cannabis were cannabinoids. Nowadays, scientists are investigating the effects of terpenes. An interesting example is the terpene myrcene, which has been shown to have analgesic properties.⁸

Entourage effect

In a nutshell, this is the cannabis version for ‘the whole is greater than the sum of its parts’. The term was first introduced in 1999 as a proposed mechanism for the combinatorial effects of endocannabinoids on the human body, and more specifically related to pain relief. Over the years, the meaning of the term evolved to describe the possible interactions of the major phytocannabinoids (THC and CBD) with other chemical compounds in cannabis that give rise to unique properties for the different cannabis strains. Even though this is an intriguing hypothesis, robust evidence for the existence of the entourage effects are not available yet.

Preclinical studies

Preclinical studies are research conducted using animals, cell cultures or even computer simulations. One of the main ways research results are misinterpreted in popular science outlets is a direct translation of results in animal models to humans. Preclinical studies form the essential first steps before any compound or therapy can be tested in humans.⁹ Right now, the vast majority of information we have on cannabis-based therapies comes from preclinical studies. These results may or may not translate well to humans. So, word of advice: take all preclinical studies with a pinch of salt.

Treatment

Treatment refers to a process or a pharmaceutical that leads to an improvement in health, but in the vast majority of cases does not lead to the complete elimination of a condition.¹⁰

The overwhelming majority of drugs (with the exception of antibiotics) are treatments. They keep symptoms in check, they allow patients to live a normal life. Cannabis-based pharmaceuticals are treatments. They do not cure the underlying conditions they are used for, they simply control symptoms. This is a subtle but important distinction.

Cure

The term "cure" means that, after treatment, the patient no longer suffers from a particular medical condition any more.¹⁰ Most conditions cannot be cured! All medical professionals and biomedical researchers are extremely careful when using this term, so it could be a “red flag” when you’re reading about a cure of any medical condition.

Clinical studies

These are research studies done on people. Their aim is to evaluate medical, surgical, or behavioural interventions. They are also known as clinical trials.¹¹ There are typically three phases a drug must go through before it can be approved:

• Phase 1 is aimed at exploring the safety and side effects of a treatment and to find the correct drug dosage (usually less than one hundred people are tested, and usually lasts several months).
• Phase 2 is aimed at the effectiveness of the candidate treatment (usually a few hundred people are tested, and it can take up to two years).
• Phase 3 is essentially a ”blow-up” version of Phase 2 & 3. A few thousand people take part in this phase that can take up to four years. If the results are positive, the medication is approved.
• Phase 4 is an additional phase after approval, during which data are continued to be collected in order to assess the long-term effects of a treatment, and it’s safety and effectiveness in different countries and genetic backgrounds.

From all this, it’s obvious that developing and testing cannabis-based therapeutics, and any other medication, is a long process. What should absolutely clear, is that any medication entering clinical trials today is very unlikely to be approved for use in humans sooner than five years from now.

So that’s it! I hope this glossary will prove to be a useful collection of the most commonly used terms in cannabis related literature and help you navigate the literature. In the following articles, I will be using most of these terms, so I’ll make sure there will be a link straight back to this glossary to make your life easiest. Stay safe!

*A Pubmed search was performed using the search string (cannabis[Title/Abstract] OR THC[Title/Abstract] OR CBD[Title/Abstract]), limiting the results to articles published in the last 5 years.

References

¹ Pertwee, R. (1997). Pharmacology of cannabinoid CB1 and CB2 receptors. Pharmacology & Therapeutics, 74(2), pp.129-180.

² Rogers, N. (2015). Cannabinoid receptor with an 'identity crisis' gets a second look. Nature Medicine, 21(9), pp.966-967.

³ Zou, S. and Kumar, U. (2018). Cannabinoid Receptors and the Endocannabinoid System: Signaling and Function in the Central Nervous System. International Journal of Molecular Sciences, 19(3):833.

⁴ Fuss, J., Steinle, J., Bindila, L., Auer, M., Kirchherr, H., Lutz, B. and Gass, P. (2015). A runner’s high depends on cannabinoid receptors in mice. Proceedings of the National Academy of Sciences, 112(42), pp.13105-13108.

⁵ Maroon, J. and Bost, J. (2018). Review of the neurological benefits of phytocannabinoids. Surgical Neurology International, 9(1), p.91.

⁶ Thomas, B. and ElSohly, M. (2016). The Analytical Chemistry Of Cannabis.

⁷ Joshee, N., Dhekney, S. and Parajuli, P. (2019). Medicinal Plants. Cham: Springer International Publishing.

⁸ Jansen, C., Shimoda, L., Kawakami, J., Ang, L., Bacani, A., Baker, J., Badowski, C., Speck, M., Stokes, A., Small-Howard, A. and Turner, H. (2019). Myrcene and terpene regulation of TRPV1. Channels, 13(1), pp.344-366.

⁹ Jarvis, M. and Williams, M. (2016). Irreproducibility in Preclinical Biomedical Research: Perceptions, Uncertainties, and Knowledge Gaps00251-5). Trends in Pharmacological Sciences, 37(4), pp.290-302.

¹⁰ Pizzorno, J. (2016). Can We Say “Cure”? Integrative Medicine: A Clinician's Journal, 15(5), pp.8-12.

¹¹ National Institute on Ageing (2020). What Are Clinical Trials And Studies?. Accessed: 13 September 2020.