German study finds legal cannabis harms far outweigh the benefits

Cannabis supporters march with mock joints, with one reading 'Legalisation' at the annual Hemp Parade on August 12, 2023, in Berlin, Germany, prior to the legalisation of cannabis in the country in 2024. Picture: Omer Messinger/Getty 

The projected health damage from cannabis legalisation in Germany is estimated to be almost 20 times greater than any health benefits, according to new research.

The study says policymakers need to strike “a careful balance” in regulation, which could include potency control, taxation to discourage overuse, and public health campaigns.

The research, published in the science journal PLOS, is thought to be one of the first to quantify the trade off between health benefits and health risks associated with legalisation.

Its publication comes as fresh hearings on possible changes to Irish drug laws are due to be held at the Oireachtas drugs committee when the new Dáil term begins next week.

The German study, conducted by Afschin Gandjour of the Frankfurt School of Finance & Management, examined the potential net effect of cannabis legalisation in the country in 2024.

While initial plans were for a more comprehensive model, the compromise introduced was “more restrictive”. 

It excluded commercial sales - which there is in Canada - and only allowed limited access, through cannabis clubs and home cultivation.

Purported health benefits of legalisation included removing the dangers posed by contaminated cannabis, either of unknown content or synthetic cannabinoids.

Increase in adult cannabis consumption

The analysis for the research estimated a projected increase in adult cannabis consumption of 400,000 to 800,000 new users or 10-20% of the four million current users in Germany.

It further estimated that 1-2% of new users may develop long-term mental health problems, amounting to around 2,300 additional cases of severe long-term conditions, such as depression or psychosis.

It estimated that the impact from cannabis use disorder (CUD) harms were “approximately 19 times greater” than health gains from reduced contamination harms.

The report said: “There is a clear conflict between the goal of reducing the black market and the risk of promoting more consumption.

“The challenge for policymakers is to find a balance between these objectives by regulating the market effectively without unnecessarily increasing consumption.

“As suggested by the findings of the present study, efforts to fully eliminate the black market through comprehensive legalisation may come at the expense of public health — namely, through increased consumption and related harms.” 

Societal harm from increased cannabis use

It said the cannabis consumer’s desire for easy access to cannabis does not take into account the “societal harm” caused by increased use, such as health risks, addiction, or higher healthcare costs.

It said “careful regulation” could include regulation of cannabis THC potency, public health campaigns, and targeted taxation to discourage overuse — but not too high, it said, as to drive people back to the black market.

The first Oireachtas drugs committee — which sat in the last Dáil before the general election — examined the recommendations of the Citizens Assembly on Drugs, which published its report in January 2024.

The committee published an interim report last October — but its work fell with the election.

The second Oireachtas drugs committee failed to hold any public sessions since the formation of the new government last January. It is due to start public hearings this month.