Cannabis Use Can Leave Lasting Epigenetic Fingerprints on the Human Body, Study Suggests
A groundbreaking study published in 2023 has revealed that cannabis use may have a significant impact on the human body, not through changes in our DNA code itself, but through alterations in how that code is expressed. The research, conducted by US scientists, suggests that cannabis can induce changes in the epigenome, which serves as a series of switches that control the activation or deactivation of genes responsible for various bodily functions. These findings were further corroborated by a systematic literature review published in 2024 by researchers in Portugal.
“We observed associations between cumulative marijuana use and multiple epigenetic markers across time,” explained epidemiologist Lifang Hou from Northwestern University, shedding light on the implications of their team’s findings in 2023.
Understanding the Impact of Cannabis Use
Cannabis is a widely used substance in the US, with nearly half of Americans having experimented with it at least once, as reported by Hou and her team in their published paper. While some US states and other countries have legalized cannabis use, the full extent of its effects on human health remains unclear.
To delve deeper into this issue, the researchers analyzed data from a long-term health study involving over 1,000 adults tracked over two decades. These participants, aged between 18 and 30 at the study’s inception, provided information on their cannabis use over the years and submitted blood samples at the 15- and 20-year marks.
By examining these blood samples collected five years apart, Hou and her colleagues scrutinized the epigenetic changes, particularly DNA methylation levels, in individuals who had recently used cannabis or had a history of long-term use.
Unraveling Epigenetic Mechanisms
DNA methylation, the addition or removal of methyl groups from DNA without altering the genomic sequence, plays a crucial role in regulating gene expression by influencing how genes are interpreted by cells. Environmental and lifestyle factors can trigger these methylation changes, which may be inherited across generations, with blood biomarkers offering insights into both recent and historical exposures.
“We previously identified associations between marijuana use and the aging process as captured through DNA methylation,” stated Hou. “We aimed to further explore whether specific epigenetic factors were linked to marijuana use and whether these factors correlated with health outcomes.”
Insights from the Study
The researchers’ comprehensive analysis of participants’ cannabis use allowed them to estimate cumulative use over time as well as recent use, comparing these patterns with DNA methylation markers in their blood for detailed analysis. They identified numerous DNA methylation markers associated with recent and cumulative cannabis use in the 15- and 20-year blood samples.
“Interestingly, we consistently identified one marker that has previously been associated with tobacco use, suggesting a potential shared epigenetic regulation between tobacco and marijuana use,” Hou highlighted.
Previous studies have linked multiple epigenetic changes associated with cannabis use to various health conditions, including cellular proliferation, hormone signaling, infections, neurological disorders such as schizophrenia and bipolar disorder, and substance use disorders.
It is essential to note that while this study sheds light on the potential association between cannabis use and epigenetic changes, it does not directly establish causality or imply a direct link to health issues.
Future Perspectives
“This research has provided novel insights into the association between marijuana use and epigenetic factors,” remarked epidemiologist Drew Nannini from Northwestern University. “Further studies are required to ascertain the consistency of these associations across diverse populations. Additionally, investigations into the impact of marijuana on age-related health outcomes may offer deeper insights into the long-term effects of cannabis on health.”
The study has been published in Molecular Psychiatry, contributing valuable knowledge to the ongoing discourse on cannabis use and its potential impacts on human biology.
An earlier version of this article was published in July 2023.
