A recent study involving over 1,000 adults has revealed that cannabis use may result in significant epigenetic changes in the human body. Conducted by researchers at Northwestern University, the study indicates that cannabis may alter the epigenome, which plays a crucial role in regulating gene expression without modifying the actual DNA sequence.
The research, published in Molecular Psychiatry in 2023, highlights how these epigenetic changes could impact various bodily functions. The lead epidemiologist, Lifang Hou, stated, “We observed associations between cumulative marijuana use and multiple epigenetic markers across time.” This finding is particularly relevant given that nearly half of all Americans have tried cannabis at least once, according to Hou and her team.
The legal landscape surrounding cannabis varies significantly, with several US states and other countries allowing its use. Despite this, the long-term health effects of cannabis remain inadequately understood. To advance this understanding, researchers analyzed data collected from a long-term health study tracking participants over two decades. Individuals aged between 18 and 30 at the study’s inception provided information about their cannabis use and submitted blood samples at the 15- and 20-year marks.
By examining these blood samples, Hou and her team focused on DNA methylation levels—one of the most studied forms of epigenetic modification. This process involves the addition or removal of methyl groups from DNA, which influences how genes are read and interpreted by cells. Such modifications can be triggered by environmental and lifestyle factors and may even be inherited by future generations.
The findings revealed numerous DNA methylation markers associated with cannabis use. In blood samples collected at the 15-year mark, researchers identified 22 markers linked to recent use and 31 linked to cumulative use. In the 20-year samples, they identified 132 markers related to recent use and 16 associated with cumulative use.
Interestingly, the study consistently identified one specific marker previously associated with tobacco use, suggesting a potential shared epigenetic regulation between cannabis and tobacco. The researchers noted that multiple epigenetic changes associated with cannabis have previously been linked to various health concerns, including cellular proliferation, hormone signaling, and mental health disorders such as schizophrenia and bipolar disorder.
While the study provides valuable insights into the relationship between cannabis use and epigenetic factors, it does not establish a direct causal link between cannabis and adverse health outcomes. Drew Nannini, another epidemiologist involved in the research, emphasized the need for further investigation. “Additional studies are needed to determine whether these associations are consistently observed in different populations,” he stated. “Moreover, studies examining the effect of marijuana on age-related health outcomes may provide further insight into the long-term effect of marijuana on health.”
The comprehensive nature of the study contributes to the growing body of research on cannabis and its impacts. As the conversation around cannabis use continues to evolve, understanding its effects on health remains a priority for the scientific community.
