A recent study involving over 1,000 adults has revealed that cannabis use may leave significant marks on the human body by altering the way our genes are expressed. Researchers from Northwestern University found evidence of changes in the epigenome, which influences gene activation and deactivation, rather than altering the DNA sequence itself. The findings were published in the journal Molecular Psychiatry in July 2023.
The research highlights a growing concern surrounding cannabis, a substance widely used across the United States, with nearly half of Americans reporting they have tried it at least once. While some states have legalized its use, the health implications remain largely unexamined.
To investigate, the study analyzed data from a long-term health survey tracking participants aged 18 to 30 over two decades. Participants provided blood samples at the 15- and 20-year marks and were asked about their cannabis use throughout the study. This extensive data allowed researchers to estimate both cumulative and recent cannabis use, correlating it with epigenetic changes, specifically through DNA methylation levels.
Understanding Epigenetic Changes
DNA methylation, a key epigenetic modification, involves the addition or removal of methyl groups from DNA. This process does not alter the genetic code but affects gene expression, much like obscuring important instructions. Environmental factors and lifestyle choices, including cannabis use, can trigger these methylation changes, which may also be inherited by future generations.
According to Lifang Hou, an epidemiologist involved in the study, “We observed associations between cumulative marijuana use and multiple epigenetic markers across time.” The researchers discovered numerous DNA methylation markers linked to cannabis use in blood samples taken at various intervals. Specifically, they identified 22 markers associated with recent use and 31 with cumulative use in the 15-year samples. In the 20-year samples, the totals increased to 132 markers for recent use and 16 for cumulative use.
Furthermore, one particular epigenetic marker was consistently identified as being associated with both tobacco and cannabis use, suggesting a shared epigenetic regulation between the two substances.
Health Implications and Future Research
While the study presents significant insights into the relationship between cannabis use and epigenetic changes, it stops short of establishing a direct cause-effect relationship regarding health outcomes. Previous research has linked similar epigenetic changes to various health issues, including hormonal signaling, neurological disorders, and substance use disorders. As Drew Nannini, another epidemiologist from Northwestern University, pointed out, “This research has provided novel insights into the association between marijuana use and epigenetic factors.”
The findings underscore the need for further investigation. Additional studies are essential to assess whether these associations are consistent across different populations and to explore the long-term health implications of cannabis use, particularly in relation to age-related health outcomes.
As public interest in cannabis continues to grow, understanding its potential effects on health through mechanisms like epigenetic changes will be crucial for informing both policy and personal health decisions.
