More than 80 so-called cannabinoids are to be found in the hemp varieties Cannabis sativa and Cannabis indica. One of these active ingredients is cannabidiol, CBD for short. In contrast to tetrahydrocannabinol (THC), CBD does not have a psychoactive and euphorigenic effect, but rather a calming one.
While legal cannabis exhibits a CBD content of 10 to 20 per cent and a residual THC content ranging from 0.3 to 0.7 per cent, the THC content of intoxicating marihuana lies at 10 to 15 per cent. Doctors are increasingly using CBD for epilepsy and psychoses; the active ingredient is also said to have a soporific, anti-inflammatory and anti-bacterial effect. Valid clinical data on the action of CBD is not currently available. Instead, legal sales of weed are bringing record profits to the sellers and causing frustration to the police. What has triggered this CBD boom and what are the risks currently associated with it? We have discussed this with Swiss cannabis researcher Prof. Rudolf Brenneisen.
„CBD was overshadowed by THC and discriminated against“
Cannabidiol is currently experiencing a boom. CBD is purported to have therapeutic effects against epilepsy, anxiety disorders, insomnia, nausea, psychosis, depression and, according to laboratory trials, even against cancer. What is currently known for certain?
According to the data from Swissmedic, antioxidant, anti-inflammatory, anticonvulsive, antiemetic, anxiolytic, hypnotic and antipsychotic effects are being considered as possible therapeutic effects. According to the assessment by Dr. Franjo Grotenhermen (Franjo Grotenhermen, Klaus Häußermann: Cannabis. Verordnungshilfe für Ärzte, Wissenschaftliche Verlagsgesellschaft 2017) the following areas of application can be considered:
- Epilepsy, especially Dravet syndrome and Lennox-Gastaut syndrome
- Anxiety disorders
- Schizophrenic psychoses
- Inflammations and pain resulting from inflammation
- Movement disorders such as dystonia and dyskinesia
- Nausea and vomiting
However, there are currently only a few controlled studies available. Cannabis researcher and pharmacist Prof. Raphael Mechoulam, the discoverer of the endocannabinoid systems of the nervous system, has already listed facts from an in vitro study which show the neuroprotective effects of CBD on cerebral ischemia, type 1 diabetes, anxiety, rheumatoid arthritis, and cancer. His colleague Dr. Teresa Iuvone has stressed the therapeutic potential of CBD for neurodegenerative diseases such as Alzheimer’s, multiple sclerosis and Parkinson’s, with the advantage of the absence of psychotropic side effects.
For which indication do you currently see great potential for cannabidiol – and is there clinical justification for the current hype?
The aggressive publicity and marketing of CBD as a medication under the pretext of “dietary supplement” or “lifestyle drug”, inciting false hope for patients, is dubious. In the process, many claims lack any scientific foundation. Positive patient testimonials lacking in sufficient scientific evaluation are also problematic here and distort the image. However: these patient testimonials should not be ignored and ought to provide an impetus for corresponding clinical studies. The hurdles are certainly financing and research co-operations. In my estimation, CBD has an opportunity as a niche player where established medication fails.
GW Pharmaceuticals has just shown positive results from medications based on CBD extracts in clinical studies with children. CBD had a positive impact on certain forms of epilepsy, such as Dravet syndrome and Lennox-Gastaut syndrome. Have the benefits of CBD been underestimated until now?
Yes, since CBD was still being overshadowed by the active ingredient THC until a few years ago and was discriminated against as a pharmacologically ineffective industrial hemp/primary cannabinoid. It was only following in vitro studies that the highly complex pharmacology and the underestimated therapeutic potential of CBD came to light. Jointly responsible were naturally the touching story of Charlotte, as well as the global media and internet hype concerning the Rick Simpson oil.
The CBD extract is currently being considered for approval as a medicine by the American Food and Drug Administration, which would give doctors a defined path enabling them to prescribe it.
Yes, the results of the American epilepsy study by GW Pharmaceuticals using isolated CBD purely from CBD cannabis, in other words not an extract in the pharmaceutical sense, are so promising that an accelerated approval process can also be expected outside the USA. It is a classic case of compassionate use, in other words the use of a yet to be approved drug on patients in particularly difficult cases of illness, which cannot be treated satisfactorily with the authorised drugs.
Neither in Switzerland nor in a country with comparable drug controls has a mono-preparation with pure CBD been approved. Which risks are associated with CBD products?
In accordance with the clinical experiences and pharmacological level of knowledge, the physical and psychological toxicity of CBD is very low. The FDA, the strictest drug authority in the world, would otherwise not have virtually waved the study from GW Pharmaceuticals through in an accelerated approval process. This is also supported by the barely observed side effects, and that even in very high therapeutic dosages in the gramme range.
In Germany, CBD is a recognised active ingredient and only available from pharmacies. Would this regulation also be advisable for other countries, and what is the situation in Switzerland?
In Switzerland, not least on account of the CBD hype, the use of CBD as a mono substance in extemporaneous preparations or formula drugs is no longer possible as of recently. The previous possibility for dispensation via pharmacies has been revoked – something that I admittedly view to be a mistake and an overreaction by the authorities to the CBD hype. An adjustment in line with the German legal situation would be expedient for all those patients for whom access to the CBD extemporaneous preparation is temporarily barred.
CBD flowers are expensive due to the many years of laborious preparation behind them. High investment costs are necessary in order to develop genetically stable plants with large flowers, high CBD and low THC content. Will many producers ultimately be disappointed by the current “gold-rush atmosphere”?
Even after the temporary ban on CBD as a medication there continue to be profitable marketing possibilities, perhaps in the form of dietary supplements, foodstuffs, cosmetics, care products, tobacco substitutes such as liquids for e-cigarettes, as well as scented oils. Conditio sine qua non is certainly the quality control by the producer and supplier. Furthermore, according to the narcotics law, the sale of CBD-rich and low-THC cannabis, this being about one per cent of the total cannabis containing THC, continues to be permitted in Switzerland and will dominate in terms of turnover.
Rudolf Brenneisen (67) is professor of pharmacy and is considered to be one of the leading international cannabis researchers. He worked as an external chemist and analyst for the US drug authority DEA and, from 1998 until 2014, was head of the research group at the department of clinical research University of Bern. He is a member of the Swiss working group for cannabinoids in medicine.