German flag surrounded by cannabis plants

Germany decriminalised cannabis: why the UK should consider doing the same

The German government has approved new legislation which decriminalises cannabis.

This policy allows over-18s to possess a maximum of 25 grams of cannabis for personal use and grow up to three plants at home.

From July 2024, German residents will also be able to join not-for-profit cannabis social clubs or growers associations where plants are cultivated en masse for the benefit of members.

In the UK, on the other hand, the government continues to support prohibition, unlike many western countries – including MaltaCanada and several states in the US – which have opened up access to cannabis in recent years.

The UK government cites concerns about the risk to mental health associated with using cannabis as a justification for supporting prohibition.

Cannabis and mental health

There is extensive research exploring the relationship between cannabis and mental health problems, such as psychosis. However, no causal link has been established because to run such studies would be unethical.

There is, though, a significant association between cannabis and psychosis. The evidence suggests that some people may be more vulnerable than others to developing psychosis through cannabis use.

Although these health concerns are shared by some organisations in Germany, this has not prevented policy reform.

The German cannabis clubs will have quality control as part of their ethos, providing information about potency and any potential contaminants.

This is important as the evidence suggests there is a dose-response relationship – an association between the amount consumed and the incidence of effect – between the strength and frequency of cannabis use and the risk of developing problems such as psychosis.

Cannabis users who experience psychosis are very few when compared to the total number using the drug. One study estimated that to avoid one person developing psychosis, up to 10,000 men and 29,000 women aged 20-24 would need to be prevented from using cannabis.

The risk to mental health associated with cannabis, then, is relatively low.

Alcohol and tobacco: regulated but riskier

Unlike cannabis, alcohol is regulated in the UK. Although there are restrictions on its use, these have been loosened in recent years. As with cannabis, there are risks to mental health as a consequence of using alcohol.

The risk of developing depression among heavy alcohol use is significant: one in two will experience depression. So despite alcohol being regulated or legal, the risks to a person’s mental health are greater than those posed by cannabis.


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For the full article by Professor Mark Monahan visit the Conversation.


Notes for editors

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