
Cannabis use may leave significant markers on the body’s genetic expression, according to a study involving over 1,000 adults. Researchers from Northwestern University discovered that cannabis could induce changes in the epigenome, which influences how genes are activated or deactivated, rather than altering the DNA sequence itself. The findings were published in the journal Molecular Psychiatry in 2023.
The study highlights the growing prevalence of cannabis use in the United States, where nearly half of adults have tried the substance at least once. Despite its legalization in various states and countries, the long-term health effects of cannabis remain poorly understood. To address this gap, the research team analyzed data from a comprehensive health study that followed participants over a span of two decades.
Participants, aged between 18 and 30 years at the study’s inception, provided detailed accounts of their cannabis use and submitted blood samples at 15 and 20 years into the study. The researchers focused on DNA methylation levels—one of the most well-researched forms of epigenetic modification. This process involves adding or removing methyl groups from DNA, affecting how cells interpret genetic instructions without altering the underlying DNA sequence.
Lifang Hou, an epidemiologist involved in the research, explained, “We observed associations between cumulative marijuana use and multiple epigenetic markers across time.” The comprehensive tracking enabled the researchers to correlate the duration and intensity of cannabis use with specific epigenetic changes.
The analysis revealed numerous significant markers in the blood samples. In the samples taken at the 15-year mark, the team identified 22 markers linked to recent cannabis use and 31 associated with cumulative use. By the 20-year point, the researchers found 132 markers related to recent use and 16 connected to cumulative use.
Interestingly, one persistent epigenetic marker identified in the study has been previously linked to tobacco use. This raises questions about potential shared mechanisms between the effects of tobacco and cannabis.
The implications of these findings reach beyond mere academic interest. Previous research has associated multiple epigenetic changes with health issues, including cellular proliferation, hormonal signaling, and neurological disorders such as schizophrenia and bipolar disorder.
Despite these associations, it is crucial to clarify that the study does not establish a direct causative link between cannabis use and adverse health outcomes. Drew Nannini, another epidemiologist from Northwestern University, stated, “This research has provided novel insights into the association between marijuana use and epigenetic factors. Additional studies are needed to determine whether these associations are consistently observed in different populations.”
The call for further research underscores the importance of understanding how cannabis affects health over the long term. As cannabis continues to gain acceptance and legalization in various regions, the need for comprehensive studies examining its health impacts becomes increasingly vital.
In summary, while the study offers important insights into the epigenetic effects of cannabis, much remains to be explored to fully understand its implications for health and wellbeing.