Authored by Piotr Plaskota
Preface: Use and possession of cannabis is illegal in the UK. This article does not aim to promote the illegal use of cannabis, but rather to give arguments from different perspectives.
Introduction No drug has ever sparked the same level of debate as cannabis. Governments around the world have taken different stances on their legal approaches towards how they handle this drug, from recreational legalisation in numerous states in the US to complete illegality (including medical use) in countries such as Japan.
In the UK today, it is only legal for a select few medical cases and possession and use otherwise is considered illegal. Despite this, it remains the most used drug in England and Wales, with the Home Office Crime Survey for England and Wales showing that about 7.2% of “adults” aged 16 to 59 have used it 2017/2018 – this equates to around 2.4 million people. The percentage for younger adults (16-24) is much higher, at around 16.7%, but has dropped quite dramatically compared to figures in the late 1990s and the early 2000s (see Figure 1). We will return to why this fact is of importance later on. 2
So why is this drug so commonly used despite its criminalisation? How does the drug work? Is the strategy that the UK is currently adopting the best for our society today? These are questions that I hope to probe throughout this article.
How does it work? Typically, the leaves of the cannabis plant, Cannabis sativa or Cannabis indica, contain a large variety of chemicals, however, the main component for its wide-spread use as a psychoactive chemical is tetrahydrocannabinol, or THC for short. While it is worth noting that there a few different forms of THC, for simplicity I will refer to the main psychoactive form as THC. CBD is another chemical found in cannabis and is currently gaining wide-spread praise as a non-psychoactive medicine with similar positive effects to THC.
Many of you may be aware that psychoactive substances are those that cause changes in brain function, resulting in changes in mood, awareness and behaviour (amongst other effects). In the case of cannabis users, they often experience a sense of relaxation and happiness, also commonly can suffering from symptoms like “the munchies” where they can suddenly become very hungry. The people who often argue for recreational legalisation often compare these symptoms to those of alcohol users, which can be much more violent and dangerous.
The body contains receptors called cannabinoid receptors. There are two main types: CB1 and CB2 receptors, both of which are members of the superfamily of G-protein coupled receptors.3 CB1 receptors are usually found at nerve endings, especially in the brain where they mediate release of chemical transmitters, whereas CB2 receptors are commonly found on immune-related cells and control cytokine (a form of chemical messenger) release.
Not surprisingly, these receptors usually bind substances referred to as endocannabinoids that are synthesised in the body. However, substances such as THC (a plant cannabinoid) partially mimic these and bind to the receptors which causes a variety of complex cell signalling, resulting in changes in levels of neurotransmitters that result in the side-effects we commonly see.4 If you are interested in greater depth of the pharmacological effects THC causes, you can read R.G. Pertwee’s 2008 review in British Journal of Pharmacology as the level of depth is a bit further than I can go into in this article.
A little history While it is widely known now in some parts of the world, many people are unaware that the illegalisation of cannabis in the US stemmed largely from a racist movement with the most famous figure related to this movement being Harry J. Anslinger, the first commissioner of the Federal Bureau of Narcotics. He ignored advice from the American Medical Association that were pro-cannabis at the time. The word “marijuana” is believed to have originated from the movement led by Anslinger used in association with racism linked to ethnic minorities at the time. Anslinger once stated: “There are 100,000 total marijuana smokers in the US, and most are Negroes, Hispanics, Filipinos and entertainers. Their Satanic music, jazz and swing, result from marijuana usage. This marijuana causes white women to seek sexual relations with Negroes, entertainers and any others.” It is terrible to think that in addition to the clear racist remarks that this “propaganda” worked and led to a widespread stigma surrounding the drug today.5,6
But what about the history in the UK? Cannabis was used widely in the UK in the 19th century. One famous example was Queen Victoria whose doctor gave it to her as a form of period pain relief.7 The use of cannabis decreased towards the end of the 18th century in the UK after the invention of the syringe, enabling more effective method of pain relief.7,8 The use of cannabis became illegal after Britain signed the 1925 Geneva Convention on Narcotics Control - cannabis was added to the list in this convention by the request of Egypt and Turkey. The laws following this convention were only enacted in the UK in 1928, being only slightly adapted in 1965 and have been relatively constant since then.7,9
The UK Strategy Studies suggest that cannabis is particularly harmful in young people, with some mentioning that prepubertal ages are particularly affected. The exact “dangerous period” does not appear to be distinctly defined across the literature, however one group quotes the age at pre-16.10 The reason for these effects originates from the fact that the cannabinoid receptor density varies significantly in younger ages, leading to a greater susceptibility to addiction and cause permanently attentional functions. There appears to be few effects on adults, other than the short-term effects of the drug.10 It is worth noting that that these were done generally in the late 1990s and early 2000s, so while this is still relatively recent larger studies could still be performed for more accurate results. The most recent study example I used was in the 2003, which used rats to compare the results with some the earlier studies on humans and rats.
You might be thinking now: if the effects of THC are generally safe, why isn’t cannabis legalised for adults? While there is still a lot of debate in this topic, one reason is that the legalisation for adults would still likely increase the usage in young people. Just as alcohol is consumed by many young people under the age of 18, if cannabis were to be legalised this would make the drug more accessible to young people to whom it is most dangerous.11 Another factor to consider is that cannabis is frequently used with tobacco that has its own health issues (as mentioned previously in “Is Nicotine a Dangerous Compound to Society”) such as cancer and nicotine addiction.
Conclusion This article has only touched the tip of the iceberg in the debate on cannabis and whether it is safe. I would highly recommend reading around the topic yourself (#EducateYourself) if you are interested. We saw how years of a lack of information and racism caused issues with the drug with respect to its use and went to propagate racist stereotypes at the time. More research needs to be carried out. I truly believe that educating young people on such information should be a focus at some point in the educational system, especially as these groups are most susceptible to damage caused by it use.
 Japanhemp, http://www.japanhemp.org/en/taimalaw.htm, Accessed 23/12/2018
 Gov.uk – Drug Misuse, https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/729249/drug-misuse-2018-hosb1418.pdf, Accessed 22/12/2018
 R. G. Pertwee, International Journal of Obesity, 2006, 30, S13-S18
 R. G. Pertwee, British Journal of Pharmacology, 2008, 153, 199 – 215
 Prohbtd, https://prohbtd.com/henry-anslinger-the-godfather-of-cannabis-prohibition, Accessed 23/12/2018
 Marijuana Mummy, https://www.marijuanamommy.com/in-1937-white-supremacists-began-attacking-the-word-marijuana/, Accessed 23/12/2018
 BBC, http://news.bbc.co.uk/1/hi/programmes/panorama/1632726.stm, Accessed 23/12/2018
 ISmoke, https://ismokemag.co.uk/cannabis-prohibition-british-history/, Accessed 23/12/2018
 BBC, http://news.bbc.co.uk/1/hi/programmes/panorama/4079668.stm, Accessed 23/12/2018
 M. Schneider, M. Koch, Neuropsychopharmacology, 2003, 28, 1760 – 1769
 Telegraph, https://www.telegraph.co.uk/news/2018/12/07/legalising-cannabis-could-result-extra-one-million-young-people/, Accessed 23/12/2018