Misconceptions in the field of cannabis medicines – It’s high time we set them straight

Mark WelshBlogs

There have been murmurings it seems, across many areas of the UK healthcare landscape in the last year, around cannabis medicines.  A media hot topic, this ancient plant has been receiving more focus than ever with changes to regulations driving a lot of the interest. Whilst the fire of conversation burns, we must ask whether this increase in attention has brought forward any answers or clarification, or rather, has it made it difficult to see the wood for the trees?

As a member of the scientific community, I am constantly challenging my own understanding of the clinical evidence within a given area of research. Cannabis medicines and the current situation within the UK is no exception. I am inundated with papers to read and articles to sift through, all with different messages, ideas and conclusions. However, one commonly recurring theme is the debunking of the myths and dispelling the misconceptions that are out there. Well, here I am jumping on the bandwagon to update on the current trends and thoughts that are shaping our understanding of cannabis medicines in 2020.

  1. The therapeutic potential is only from THC”? 

No, not quite. In full extract product there will be various cannabinoids and other active compounds including terpenes, flavonoids and acidic metabolites. However, the two components with the most evidence to date are THC and CBD. Both have been documented to provide various therapeutic effects and there is an evolving evidence base on each to support individual utilisation.[1],[2]

In studies looking at CBD containing only full extract products, there has been a demonstrated anxiolytic and antiepileptic therapeutic effect in the absence of THC. CBD’s dominant effect can also be observed across the Epidiolex studies and in investigatory work utilising laboratory-grade CBD isolate. Products such as Nabilone, a synthetic THC only medicine has been utilised in neuropathic pain and chemotherapy-induced nausea. These two contrasting products contain high levels of each cannabinoid and produce different therapeutic effects in symptom management. Individual needs will dictate the amount of THC required to achieve therapeutic benefit, it may be a little, it’s unlikely to be a lot. [3]

  1. Panacea or bust?

Cannabis can cure it all, can’t it? With the recent surge in clinical development and the growth of various pharmaceutical interests, it might be easy to think that this wonder drug can be used for any symptom or condition. However, this is not the case and there is a lot of research and investigatory work still required to elucidate the many effects of cannabinoids within therapeutic applications. For now what we believe to be some of the most responsive areas are within neurological conditions, oncology, and chronic pain.[4]

As the evidence evolves and further clinical research develops, we will be able to say with more confidence where cannabis is having the greatest therapeutic impact. Research into chronic conditions such as fibromyalgia[5] are underway and the utilisation of CBD in psychiatric conditions[6] has begun as well.

  1.       Legitimacy as a medicine  

Due to years of prohibitive global drug scheduling, large scale research into cannabis has been hindered and at best stop-start. The result is a lack of research in the form of large human studies and clinical trials. This poses the issue of the legitimacy of cannabis as a therapeutic product. Historically there are numerous cases of cannabis sativa being used as far back as 400AD and we have all heard that Queen Victoria used it for pain relief for migraines.[7] However as medical advancements quicken and the demand for robust clinical evidence is shouted down, we need to understand the growing evidence and appreciate the current clinical evidence on the matter. Cannabis is fast becoming a legitimate therapy and less of an illicit substance every year.

  1.       Overdosing

‘You can’t overdose on cannabis’ ‘it’s a plant, there’s nothing in it that makes you ill’. And yes, in theory these points have some validity and we can debate these till the plants are dried, however here is some balanced evidence on the matter:

Yes, you can overdose on cannabis, however the quantity and rate of administration required is incredibly large and short, respectively. In practise a near impossible task for example, an animal study showed, the non-fatal consumption of 3000 mg/kg THC by a monkey would be a comparable dose to over 20kg THC in humans. [8]  

A recent study, using mice, investigators looked to understand the impact of high CBD extract dosing, and any resulting hepatotoxicity. In conclusion the study reported a dose of 2460mg/kg in mice producing hepatotoxicity which translates to a human equivalent of 200mg/kg CBD. [9]

Again, as with all medication there is a therapeutic window of efficacy and toxicity. Medicinal cannabis is no exception to the rule, and at this early stage in the growing utilisation, monitoring and adverse event reporting is key to understanding the full safety profile of this individualised medicine. 

  1.       All hemp is cannabis, but not all cannabis is hemp

    Reference to hemp, is typically concerned with ‘industrial hemp’; an agricultural crop with long, strong fibres. Mainly used in clothing, paper, (animal) feed, and other industries, industrial hemp contains negligible or zero levels of THC. Industrial hemp does however contain CBD and as a result it is sometimes also used to produce CBD rich oils, these will not be used in products manufactured for medical use.

Cannabis-based medicines are harvested and extracted from plants that contain more than 0.4% THC by weight. These plants are generally thinner, with thin leaves in comparison to plants harvested for industrial hemp. Ultimately plants utilised in medicinal grade products are from plant varieties containing more than 0.4% THC. 

  1.       Will medicinal cannabis get you ‘high’ ?

Reflecting on the emerging evidence around the various formulations of cannabis medicines and the contrasting evidence and limited research done investigating recreational use, it is hard to define which medication will produce a psychoactive high for any given patient. What is known is that there is a vast difference between the Active Pharmaceutical Ingredient (API) in recreational and medicinal products.
Recreational products tend to focus on high THC varieties and are bred to give you a euphoric high. This may mitigate certain disease symptoms, however it most likely goes above and beyond the required therapeutic levels of THC required as observed in medicinal therapeutic products.[10] Medicinal cannabis formulations vary as well and whilst there are manufacturers of high THC formulations, many of these products contain CBD in order to provide a mitigating effect to the psychoactive high.
As the medicinal cannabis market grows the availability of personalised formulations are becoming available and many licensed producers offer a spectrum of concentrations.

Whilst individual patients may experience a sensation of high with medicinal cannabis products, the argument presented here is that patients are not actively seeking this experience and are looking to maximise the therapeutic effects of cannabis based medicines.

  1.       “There is no evidence for medicinal benefit” 

The current evidence base is evolving, and as legislation changes globally, the opportunity for larger clinical research endeavours can take place. As of February 2020 there were over 5000 clinical paper publications available on PubMed, specifically focusing on medicinal cannabis. This increase has been reviewed and estimated that there has been a 9 fold increase in publications from 2000-2017.[11]

While there has been no positive position statement from NICE, EMA or a Royal College the increase in research, expansion of clinical networks and the opening of national clinics dedicated to treating patients with cannabis medicines indicates positive development in this space. Notably the British Pain Society recently issued a position statement detailing their acknowledgement towards patients who have benefited from the use of medicinal cannabis.[12]

  1.       Long term effects

Good clinical practise and monitoring, speaking to a trusted doctor, remaining informed and knowing what you’re getting.

There is a limited consensus on the long-term effects and little documented evidence around the risks and longer term benefits of medicinal cannabis use.[13] Anecdotally, there is evidence to suggest both tolerability and conversely to suggest the potential for hepatotoxicity and psychosis. Whilst this isn’t uncommon with many medicines, cannabis has come under greater scrutiny due to its illegal status and lack of large scale randomised clinical trials.

Continued monitoring and data collection are key to further understand the long-term effects of medicinal cannabis use and ultimately will help to inform pathways and guidelines for future utilisation.

  1.       Who’s it all for?

Good question, and who can say, apart from the individual patient in question and an experienced medicinal cannabis practitioner. Cannabis medicines may be a therapeutic treatment consideration for you, however as with all medication there is no guarantee it will address your treatment needs. Like all medication there is a specific group of individuals who may benefit from treatment and those who will not.

Cannabis medicines offer another avenue of treatment and therapy choice for many patients who have reached what they and clinicians feel is the end of their treatment. Ultimately, another tool in the toolbox in the treatment of chronic conditions.

Misconceptions have formed due to a lack of access to develop quality information and aspersions cast from an installed view of hysteria and danger. The current reality is that we’re moving towards a progressive position on the humble plant, one built on the further understanding of its potential therapeutic action and value. Whilst there have been many strides forward in cannabinoid medicine there is a long way to go to cementing medicinal cannabis position fully, as a widely credible therapy.  

For any information or answers to any questions you may have on this new treatment option, please don’t hesitate to get in touch via the details at the bottom of the page.


[1] Campos, A., Fogaça, M., Sonego, A. and Guimarães, F. (2016). Cannabidiol, neuroprotection and neuropsychiatric disorders. Pharmacological Research, 112, pp.119-127.

[2] Lötsch, J., Weyer-Menkhoff, I. and Tegeder, I. (2017). Current evidence of cannabinoid-based analgesia obtained in preclinical and human experimental settings. European Journal of Pain, 22(3), pp.471-484.

[3] Broers, B., Patà, Z., Mina, A., Wampfler, J., de Saussure, C. and Pautex, S. (2019). Prescription of a THC/CBD-Based Medication to Patients with Dementia: A Pilot Study in Geneva. Medical Cannabis and Cannabinoids, 2(1), pp.56-59.

[4] Nice.org.uk. (2019). Recommendations | Cannabis-based medicinal products | Guidance | NICE. [online] Available at: https://www.nice.org.uk/guidance/ng144/chapter/Recommendations [Accessed Feb. 2020].

[5] Clinicaltrials.gov. (2020). Phase II Clinical Trial, Use of KL16-012 in Women With Fibromyalgia Refractary to Conventional Treatment. – Full Text View – ClinicalTrials.gov. [online] Available at: https://clinicaltrials.gov/show/NCT04239469 [Accessed Feb. 2020].

[6] Clinicaltrials.gov. (2020). Cannabidiol for Treatment of Recent-onset Psychosis With Comorbid Cannabis Use – Full Text View – ClinicalTrials.gov. [online] Available at: https://clinicaltrials.gov/show/NCT04105231 [Accessed Feb. 2020].

[7] Zlas, J., Stark, H., Seligman, J., Levy, R., Werker, E., Breuer, A. and Mechoulam, R. (1993). Early medical use of cannabis. Nature, 363(6426), pp.215-215.

[8] Thompson, G., Fleischman, R., Rosenkrantz, H. and Braude, M. (1974). Oral and intravenous toxicity of Δ9-tetrahydrocannabinol in rhesus monkeys. Toxicology and Applied Pharmacology, 27(3), pp.648-665.

[9] Ewing, L., Skinner, C., Quick, C., Kennon-McGill, S., McGill, M., Walker, L., ElSohly, M., Gurley, B. and Koturbash, I. (2019). Hepatotoxicity of a Cannabidiol-Rich Cannabis Extract in the Mouse Model. Molecules, 24(9), p.1694.

[10] Freeman, T., Groshkova, T., Cunningham, A., Sedefov, R., Griffiths, P. and Lynskey, M. (2019). Increasing potency and price of cannabis in Europe, 2006-16. Addiction, 114(6), pp.1015-1023.

[11] Treister-Goltzman, Y., Freud, T., Press, Y. and Peleg, R. (2019). Trends in Publications on Medical Cannabis from the Year 2000. Population Health Management, 22(4), pp.362-368.

[12] Britishpainsociety.org. (2019). BPS Position Statement on the medicinal use of cannabinoids in pain management | News | British Pain Society. [online] Available at: https://www.britishpainsociety.org/mediacentre/news/bps-position-statement-on-the-medicinal-use-of-cannabinoids-in-pain-management/ [Accessed Feb. 2020].

[13] Lovell, M., Bruno, R., Johnston, J., Matthews, A., McGregor, I., Allsop, D. and Lintzeris, N. (2018). Cognitive, physical, and mental health outcomes between long-term cannabis and tobacco users. Addictive Behaviors, 79, pp.178-188.