Cannabis use may cause lasting changes to gene activity: Study

Cannabis use may leave lasting fingerprints on the human body, a study of over 1,000 adults suggests - not in our DNA code itself, but in how that code is expressed.

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US researchers found it may cause changes in the epigenome, which acts like a set of switches that activate or deactivate genes involved in how our bodies function.

"We observed associations between cumulative marijuana use and multiple epigenetic markers across time," explained epidemiologist Lifang Hou from Northwestern University when the research was published in 2023.

Cannabis is a commonly used substance in the US, with nearly half of Americans having tried it at least once, Hou and team report in their published paper.

Some US states and other countries have made cannabis use legal, but we still don't fully understand its effects on our health.

To investigate this, the researchers analyzed data from a long-running health study that had tracked around 1,000 adults over two decades.

Participants, who were between 18 and 30 years old when the study began, were surveyed about their cannabis use over the years and gave blood samples at the 15and 20-year marks.