Original questions: “Is there evidence that the decriminalisation of drugs benefits society?” asks Leo, “Should we legalise illegal drugs?” asks Jack, and “Would the decriminalisation of drugs (recreational or otherwise) be beneficial?” asks Edward

Thank you for your questions! How the law fits with drugs is a highly complex issue. It requires firm understanding of international and national history, psychology, sociology, biology, the law, and, perhaps most importantly, ethics. No-one can give definite answers because as with many complex issues, it will always end up in a trade-off based on a risk-benefit analysis. I will comment on a few points of scientific evidence that I find to be most intriguing and relevant to your questions. Before we discuss these two questions, it is important to distinguish between ‘decriminalise’ and ‘legalise’. ‘Decriminalisation’ proposes a system where those that are in possession of personal amounts of drugs will not leave you with a criminal record, but could result in other interventions such as therapy, fines, or classes. For example, parking on double yellows is not legal, but it won’t result in you serving jail-time!). ‘Legalisation’ permits the use, and one can assume by extension, the manufacturing and distribution of drugs.

When discussing drugs and the law, we should consider why laws like these exist. The answer is somewhat foggy, and is firmly tied into international politics and public perception. Historically, drug laws like the alcohol prohibition in the US during the 1920’s existed for ‘harm reduction reasons’. The move to prohibit alcohol aimed to combat corruption in the alcohol trade, reducing alcoholism and attempted to usher in a new age of social and health stability. After the backlash and upheaval of this law, our views on drugs have changed with our laws now reflecting a range of interests aside from ‘harm reduction’. Many pressures globally have resulted in our current view on drugs, alongside the media weaving our current perceptions that drugs are ‘dangerous’ and should remain illegal, even whilst the same people continue consuming drugs such as alcohol and caffeine without questioning their harm. So where does science stand with all this?

Well, first, let’s talk about harm reduction. I define ‘harm’ as ‘harm on society, individuals and their rights’. The famous (or infamous depending on your outlook) Professor David Nutt, the former government chief advisor, published findings in The Lancet regarding the harm caused by drugs both to the individual and to society (Nutt, King, & Phillips, 2010). Their analysis found that alcohol was the highest scoring, however, Prof Nutt did note that these findings also reflect the current widespread usage of alcohol across our society.


Bar chart showing Nutt et al.’s (2010) findings on harm of drug use - image accessible through http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)61462-6/fulltext

Taking the ratings for ‘harm to individuals’ alone, it becomes clear that ‘illegal’ drugs in our country, cannabis for example, are rated far lower than legal drugs. More recent findings from Lachenmeir and Reim (2015) support this ranking by conducting an analysis on analysis using the ‘margin of exposure’ (or MOE) - “a tool used by risk assessors to consider possible safety concerns arising from the presence in food and feed of substances which are both genotoxic (they may damage DNA) and carcinogenic” (EFSA, 2012; for more on this see Lachenmeir, & Reim, 2015).


Margin of Exposure analysis conducted by Lachenmeir and Reim (2015) on a range of drugs based on individual consumption (lower ratio indicates greater risk) - image retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4311234/

Evidence is mounting to suggest that our current judicial system is failing to curb the criminal drugs trade, or even reduce addiction to drugs. More authoritative committees are calling out for either the decriminalisation or legalisation of drugs with both solutions consisting a range of pros and cons.

First, let’s talk about decriminalisation. The decriminalisation of drugs would restrict drug usage and by extension potential harm to users, but would allow society to treat drug dependencies with therapy rather than jail-time. This would solve a lot of society’s problems and prevent further dangerous consumption in the future. This is true harm reduction. It also serves as a resolution to the issue of the ‘revolving door’ in our homeless population. To illustrate this, imagine someone is homeless and turns to drugs to deal with their situation. They develop a dependence, they commit crimes such as theft to fund their dependence, and in doing so they are caught and jailed. When they are released, they still have no home and resort to their dependence again - and so, the cycle continues. As a psychologist, I know all too well that addressing the root of someone’s problem is the best way to prevent negative behaviour in the future.

From an ethical perspective, it would also prevent a criminal record and/or jail-time which could negatively impact future life opportunities. This is because drug taking, from a health perspective, is a relatively harmless act when compared to other aspects of society leading to deaths (e.g. pollution, road-traffic accidents, and even alcohol deaths). Another benefit to decriminalisation would be the freeing up of police-time allowing other, potentially more threatening crimes, to be attended to more rapidly. To top-off the evidence of why decriminalisation should not be feared, Prof Alison Ritter, a world-leading drug policy scholar, has demonstrated that there is good evidence that drug usage does not increase because of decriminalisation.

Now, let’s talk about legalisation. Legalisation could lead to a safer community through regulation, and the prevention of overdoses (using techniques much like how paracetamol is sold in the UK). The idea of legalising cannabis is gaining traction, with the realisation of its harm levels comparative to legal drugs; alongside its potential benefits to the economy and its ethical approach to the problem of jailing those in possession of cannabis. However, data is currently limited on how legalisation affects uptake of drugs, as there are not enough countries taking this approach for conclusions to be made. Therefore, careful consideration of legalisation of harder drugs that could cause great harm, such as heroin, should be treated with caution. Further study is inevitably required before we can make decisions on this.

To conclude, a lot of this is hotly debated, and there are no firm answers as to how the law should handle drugs. However, from a scientific perspective, a move to at least decriminalise low-harm drugs is encouraged. It is my opinion, based on the evidence, that cannabis should be legalised and regulated by state due to the low personal and societal harm as well as the benefits that can be achieved both economically and socially. Other drugs, however, should be decriminalised on usage but kept illegal in manufacturing and distribution. This is purely so that those that are struggling from drug dependence can get the treatment they require and live healthier lives rather than receiving jail-time.

A final point I would like to make is that alcohol does a lot of damage to our society, and I feel that we need to work harder on educating proper use of alcohol as well as other drugs. All drugs have potential negative consequences, and as the saying goes: “The dose makes the poison”.


EFSA. (Mar, 2012). Margin of Exposure. Retrieved October 21, 2017, from https://www.efsa.europa.eu/en/topics/topic/margin-exposure Lachenmeier, D. W., & Rehm, J. (2015). Comparative risk assessment of alcohol, tobacco, cannabis and other illicit drugs using the margin of exposure approach. Scientific reports, 5.

NHS. (Nov, 2010). Study compares drug harms. Retrieved October 21, 2017, from https://www.nhs.uk/news/lifestyle-and-exercise/study-compares-drug-harms/

Nutt, D. J., King, L. A., & Phillips, L. D. (2010). Drug harms in the UK: a multicriteria decision analysis. The Lancet, 376(9752), 1558-1565.

Ritter, A. (Apr, 2012). Decriminalisation or legalisation: injecting evidence in the drug law reform debate. Retrieved October 21, 2017, from https://ndarc.med.unsw.edu.au/blog/decriminalisation-or-legalisation-injecting-evidence-drug-law-reform-debate