Cannabis use leaves a unique mark on the DNA of the user, found a recent study by the Institute of Psychiatry, Psychology and Neuroscience (IoPPN) at King’s College London (KCL) and the University of Exeter.
This article was originally published in print on 28 November.
Researchers found that high-potency marijuana (THC content of 10% or higher) changes DNA methylation patterns. DNA methylation is the process by which the body turns genes off – it determines whether a gene is expressed or not.
Humans have many genes in their genome. Made of DNA, genes are responsible for different tasks such as muscle and bone growth, as well as immune system regulation. The body cannot express all genes at once, and must therefore be able to switch genes on or off. Think of it like this: the human genome is like a toolbox and the genes are the tools. The body must decide which combination of tools to use depending on its current needs. One method of choosing the correct tools is DNA methylation.
Findings
The researchers made some intriguing discoveries by analysing DNA methylation in the whole human genome using blood samples from cannabis users and non-users.
Most importantly, they found that DNA methylation patterns were different in cannabis users, specifically in genes involved in mitochondrial and immune system function. This suggests that cannabis may negatively impact energy levels in the body and its ability to fight infection.
Why does it matter?
The effects of marijuana on the brain are still unclear and cannabis use is increasingly being legalised and normalised around the world, making research in this fast-developing area of science even more necessary.
Although marijuana is illegal to possess, grow and distribute, a shockingly high proportion of university students admit to using the drug. A 2018 national survey showed that cannabis is the most common and regularly used drug in a sample of 2810 students, with 53% saying they had taken it.
Many individuals believe that cannabis use is safe and causes fewer side effects compared to other drugs. While it’s true that cannabis usually doesn’t cause immediate severe reactions and is less addictive, we should consider the drug’s long-term effects on the brain and body. Some effects include problems with attention and memory, breathing issues and depression.
‘Cannabis and Me’ Project
In 2022, KCL invested a whopping 2.5 million pounds into a project called ‘Cannabis and Me‘, led by Dr Marta di Forti, Professor of Drug use, Genetics and Psychosis at the IoPPN. Through it, researchers aim to pinpoint specific genetic or environmental traits that are likely to cause mental health problems in cannabis users. Such studies are vital to understand the full picture of cannabis use and, eventually, when and how to prescribe it safely.
It is evident that the area of cannabis research is still new and the exact effects of cannabis are yet to be revealed. However, we are now seeing a great number of studies conducted in the field and are well on track to fully understanding how the drug works.
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