A new study of people using high-potency cannabis has found the drug may leave a mark on the user’s DNA and also appears to have a link to people experiencing their first episode of psychosis. For this study, high-potency cannabis was defined as containing over 10% Delta-9-tetrahydrocannabinol (THC), the plant’s main psychoactive ingredient.
According to the study authors, understanding these links could prove critical in identifying risks for recreational and medicinal users. This includes potentially developing a blood test to determine which patients are most at risk of experiencing a psychotic episode when using cannabis, particularly those using high-potency cannabis products.
“Our study is the first to show high potency cannabis leaves a unique signature on DNA related to mechanisms around the immune system and energy production,” explained the study’s senior author, Marta Di Forti, Professor of Drugs, Genes, and Psychosis at King’s College London’s Institute of Psychiatry, Psychology & Neuroscience (IoPPN). “Future research needs to explore if the DNA signature for current cannabis use, and in particular one of the high-potency types, can help identify those users most at risk to develop psychosis, both in recreational and medicinal use settings.”
High-Potency Cannabis and DNA Methylation
The research team made their discovery by analyzing chemicals in the blood related to DNA methylation. Unlike a process that alters the genetic code contained within DNA, methylation affects which genes are expressed, meaning which are turned “on” or turned “off.” According to the press release announcing the team’s study, DNA methylation “is considered a vital factor in the interplay between risk factors and mental health.”
“Our findings provide important insights into how cannabis use may alter biological processes,” explained Dr. Emma Dempster, Senior Lecturer at the University of Exeter and the study’s first author. “DNA methylation, which bridges the gap between genetics and environmental factors, is a key mechanism that allows external influences, such as substance use, to impact gene activity.”
In their study, the team evaluated the DNA methylation of 682 study participants across the entire human genome using blood samples taken from each participant. Alongside the use of high-potency cannabis, the team sorted the users into those who had experienced their first psychotic episode (239) and those who had never experienced a psychotic episode (443). They also looked for the frequency of cannabis use, especially in participants who used more potent strains of cannabis.
This analysis found several interesting correlations in high-potency cannabis users. For example, the blood tests revealed measurable changes in genes related to mitochondrial function and the immune system. Among the most prevalent was a measurable change in the expression of the CAVIN1 gene, which affects energy and immune system responses.
“This is the first study to show that frequent use of high-potency cannabis leaves a distinct molecular mark on DNA, particularly affecting genes related to energy and immune function,” Demptster said
“These epigenetic changes, shaped by lifestyle and exposures, offer a valuable perspective on how cannabis use may influence mental health through biological pathways.”
Notably, the researchers said these changes were not accounted for by the “well-established” effects on DNA methylation by tobacco that many of the users mixed into their cannabis joints.
Mental Health and Cannabis
While this is only a first step, the team says that understanding the effect of cannabis use on mental health is a pressing concern given the increased access due to changes in the laws governing cannabis possession worldwide. This is especially significant given the increased potency of cannabis in recent decades.
“With the increasing prevalence of cannabis use and more availability of high potency cannabis, there is a pressing need to better understand its biological impact, particularly on mental health.” Di Forti said.
The study “‘Methylomic signature of 1 current cannabis use in two first-episode psychosis cohorts” was published in Molecular Psychiatry.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.