New Study Links Excess Cannabis Use to Numerous Health Problems

Cannabis Genetics

A Yale study analyzing the genomes of over 1 million people has uncovered genetic factors linked to cannabis use disorder and its potential connections to psychiatric issues, substance abuse, and lung cancer risk, highlighting the importance of understanding marijuana’s health implications. Credit: Illustration by Michael S. Helfenbein

A comprehensive study conducted by researchers from Yale, involving the analysis of over one million individuals’ genomes, has provided new insights into the biology of cannabis use disorder. This study also explores its connections to various psychiatric conditions, the tendency to abuse other substances like tobacco, and the potential increased risk of lung cancer associated with cannabis use.

For the study, researchers examined a genome-wide set of genetic variants in individuals from multiple ancestry groups enrolled in the U.S. Department of Veterans Affairs’ Million Veteran Program, one of the world’s largest genetic databases, and incorporated additional information from several other genomic databases. They were able to identify dozens of genetic variants linked to cannabis use disorder and a variety of behavioral and health issues associated with cannabis use disorder.

Understanding the Risks of Marijuana Use

The study, led by Daniel Levey, assistant professor of psychiatry, and Joel Gelernter, the Foundations Fund Professor of Psychiatry and professor of genetics and neuroscience, was published Nov. 20 in the journal Nature Genetics.

“Once we understand the biology of cannabis use disorder, we can better understand associated disorders and inform the public of risks associated with marijuana use,” said Levey, lead author of the study.

Marijuana is the most commonly used federally illegal drug in the United States, with more than 48 million people (18% of Americans) using it at least once in 2019, according to the U.S. Centers for Disease Control and Prevention. Previous research has shown that roughly one-third of people who use marijuana develop cannabis use disorder, which is defined as a problematic pattern of cannabis use leading to clinically significant impairment or distress.

Genetic Factors and Health Risks Associated with Cannabis Use

The new findings offer insights into the genetic factors that underlie this phenomenon and other potentially related health risks.

For instance, they found that variants of genes that encode for three different types of receptors on neurons were associated with an elevated risk of developing cannabis use disorder.

And they found that these variants linked to cannabis use disorder were also associated with the development of lung cancer. The authors added, however, that more work needs to be done to separate the effects tobacco use and other environmental factors have on cancer diagnoses from those of marijuana use.

“This is the largest genome-wide study of cannabis use disorder ever conducted and as more states legalize or decriminalize the use of marijuana, such studies can help us to understand the public health risks that accompany its increased use,” Gelernter said.

Reference: “Multi-ancestry genome-wide association study of cannabis use disorder yields insight into disease biology and public health implications” by Daniel F. Levey, Marco Galimberti, Joseph D. Deak, Frank R. Wendt, Arjun Bhattacharya, Dora Koller, Kelly M. Harrington, Rachel Quaden, Emma C. Johnson, Priya Gupta, Mahantesh Biradar, Max Lam, Megan Cooke, Veera M. Rajagopal, Stefany L. L. Empke, Hang Zhou, Yaira Z. Nunez, Henry R. Kranzler, Howard J. Edenberg, Arpana Agrawal, Jordan W. Smoller, Todd Lencz, David M. Hougaard, Anders D. Børglum, Ditte Demontis, Veterans Affairs Million Veteran Program, J. Michael Gaziano, Michael J. Gandal, Renato Polimanti, Murray B. Stein and Joel Gelernter, 20 November 2023, Nature Genetics.
DOI: 10.1038/s41588-023-01563-z

3 Comments on "New Study Links Excess Cannabis Use to Numerous Health Problems"

  1. “…more work needs to be done to separate the effects tobacco use and other environmental factors have on cancer diagnoses from those of marijuana use.”

    That pretty much sums this study up. — The country’s leading researcher of cannabis and lung disease, UCLA’s Dr. Donald Tashkin, conducted investigations over 30 years, initially believing there must be a causal relationship. But he finally concluded that smoking cannabis  does NOT cause cancer or ANY other serious disease.

    Tashkin said: “We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use. What we found instead was no association at all, and even some suggestion of a protective effect.”

    The DEA’s own administrative law judge, Francis Young, concluded after an exhaustive review of the evidence: “Marijuana, in its natural form, is one of the safest therapeutically active substances known to man.”

  2. Charles G. Shaver | December 23, 2023 at 4:57 am | Reply

    An excellent example of how the complete ignorance of underlying causes can result in false conclusions. First, there is a kind of nearly subclinical non-IgE-mediated allergy reaction that mainstream medicine still fails to recognize and research, which then renowned immunologist Dr. Arthur F. Coca identified, studied and reported on by 1935 (e.g., “The Pulse Test,” 1956). Then there are the FDA approved food poisoning (e.g., soy and MSG, minimally) factors which preceded the US female breast cancer epidemic (soy, by 1979) and the US obesity epidemic (MSG, by 1990). First writing the US FDA (with replies) of my early lay findings of connections between allergies, added MSG, chronic disease and obesity in October of 2005 (obviously, now, in-vain) I believe I previously tried to inform Professor Levey (among thousands of other healthcare professionals of those facts), also in-vain. For me, I believe too it should beg this question of all professional healthcare researchers: “What is causing the pain that is driving all of those people to try to escape their tortured realities with a psychoactive substance?” Then too, “Why is MSG legal and marijuana is not?”

  3. Great Post! Any study linking excess cannabis use to health problems should be critically examined for its methodology and implications. The findings should contribute to a nuanced and evidence-based conversation about the potential risks associated with cannabis consumption.

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