(Studies show using Marijuana harms the DNA which may lead to serious illness. The damaged DNA is then passed down to our children.)
"Smoking cannabis can alter a person's DNA, causing mutations that expose a user to serious illnesses," the Mail Online reports.
A new review has looked at the role cannabis may play in what is known as chromothripsis.
A relatively recent discovery, chromothripsis is when the DNA of a cell suffers large-scale damage, but not enough to kill the cell. It has been linked to some types of cancer and birth defects.
In this review, researchers considered the evidence about whether one of the active ingredients in cannabis – tetrahydrocannabinol (THC) – could trigger chromothripsis, which could potentially cause cancer and other illnesses.
The researchers also raised the possibility that the DNA damage could be passed down to later generations.
There is a great deal of uncertainty about how the included studies were chosen, so there is a possibility not all relevant research was considered.
This type of study serves to stimulate debate and further research. It is not reliable enough to form the foundation of policy change on its own.
Arguably, a longer-term study would be needed to see if cannabis use could have an intergenerational effect.
We do know that cannabis, a class B illegal drug, is known to contain cancer-causing chemicals (carcinogens) and has previously been linked with lung cancer, psychosis, schizophrenia and fertility problems.
Find out more facts about cannabis.
Where did the story come from?
The review was carried out by two researchers from the University of Western Australia. There was no external source of funding.
It was published in the peer reviewed journal, Mutation Research: Fundamental and Molecular Mechanisms of Mutagenesis.
The Mail Online's headline, "Smoking cannabis can alter a person's DNA, causing mutations that expose a user to serious illnesses", made it sound like the researchers' hypothesis was proven by newly uncovered evidence, which is not the case.
The headline and article did largely reflect the researchers' findings, but failed to add any notes of caution, balance or discussion about the limitations of the research, instead taking it at face value.
What kind of research was this?
This was an evidence-informed narrative review of research exploring the hypothesis that cannabis use causes errors in human DNA, potentially leading to cancer and affecting brain development in unborn babies.
Non-systematic reviews like this are useful for summarising scientific research in a particular area, but can miss relevant research and counter-arguments.
Without a clear and systematic review of the published and unpublished science, there is a risk the authors cherry-picked the evidence, consciously or unconsciously, to fit their views.
Such a one sided-argument has its place in stimulating debate, but should not be viewed on a par with a systematic review, one of the highest levels of evidence.
A systematic review of well-designed long-term cohort studies would be one of the best ways to assess the causal links between cannabis and DNA damage and disease.
What did the research involve?
The research is a narrative review of evidence that presents the idea that cannabis can disrupt a person's DNA, potentially raising their risk of cancer and causing genetic toxicity that could be passed from one generation to the next.
The review assembled data from 189 research articles. However, it had no reported methods. As such, we cannot assume the researchers employed systematic review methodology.
As the authors didn't mention how they found the articles, the study risks being biased to fit a coherent story, or may ha