Regular use of cannabis with high THC levels appears to leave a unique molecular mark on genes, according to a study focused on DNA methylation that sheds light on the links between cannabis and mental health.
- A new study reveals that frequent use of high-THC cannabis leaves a unique mark on DNA, changing genes related to energy and the immune system, including the CAVIN1 gene.
- The effects are nevertheless different in people who have experienced a first episode of psychosis. This discovery could make it possible, via blood tests, to identify users at risk of developing psychoses.
- The study offers new perspectives to better understand how cannabis influences mental health through biological pathways, and therefore to better prevent psychotic disorders.
THC, or Delta-9-tetrahydrocannabinol, is the main psychoactive molecule in cannabis, and its levels have been increasing for decades. For the first time, a study published in the journal Molecular Psychiatry reveals that the consumption of so-called potent cannabis, defined by a THC content greater than 10%, leaves a distinct signature on the DNA. Thus highlighting the hitherto poorly understood biological impact of this recreational drug, particularly on mental health.
High-THC cannabis leaves a unique mark on DNA
To do this, researchers from the University of Exeter, in the United Kingdom, analyzed DNA methylation, an epigenetic process that influences the expression of genes without changing their sequence, in blood samples from 682 people. from the United Kingdom, France, Spain and even Brazil. Some participants had experienced their first episode of psychosis, others had never had a psychotic experience, but most were regular users (at least once a week) of “potent” cannabis since the age of 16 approximately.
Their results first show that frequent users of cannabis with high THC levels present “changes in genes related to energy and immune functions, including the CAVIN1 gene, which could affect immune response and energy production”according to a press release. Alterations which, the study specifies, are not linked to the well-established impact of tobacco, often mixed with cannabis in the joints of those concerned, on DNA methylation. “Our study is the first to demonstrate that cannabis with a high THC content leaves a unique molecular mark on the genes”notes Professor Marta Di Forti, lead author of the work.
Understanding the link between cannabis and mental health
Another lesson: the striking difference between cannabis users who have already experienced an episode of psychosis and those who have never suffered from it. This suggests that blood tests based on these DNA signatures could ultimately help identify users at higher risk of developing psychotic disorders, whether in a recreational or medical setting.
While DNA methylation is a process that allows environmental factors, such as substance use, to influence gene activity, this study provides new insights into understanding how cannabis use may influence mental health through biological pathways. This could have major repercussions in the clinical prevention of psychotic disorders.
