Take This Marijuana Message to Heart

Smoking Pot May Put Users at Risk for Serious Heart Problems

Medically Reviewed by Louise Chang, MD on May 13, 2008

May 13, 2008 -- Smoking marijuana results in changes in the bloodstream that may put chronic users at risk for serious cardiovascular problems such as heart attack and stroke.

Researchers with the National Institute on Drug Abuse say the active chemical in marijuana, THC, causes the body to overproduce a protein called ApoC-111. ApoC-111 is linked to high triglycerides (blood fats) because of problems with the breakdown of blood fats in the body.

The study results are published in the May 13 issue of Molecular Psychiatry.

The researchers note that marijuana's effects from heavy, long-term use have been linked to neuorological problems such as learning difficulty and strokes.

Marijuana is the most commonly used illegal drug in the United States, according to the journal report.

For the study, Jean Lud Cadet, MD, with the Molecular Neuropsychiatry Branch at the National Institutes of Health Biomedical Research Council in Baltimore, and colleagues looked at blood samples from 18 regular marijuana users and 24 nonusers. They found that chronic pot smokers had significant increases in blood levels of ApoC-111. They also found an association between ApoC-111 levels and elevated levels of triglycerides.

Cadet's team says that THC binds to cannabinoid receptors that are located in different areas of the body, including the brain, heart, and liver. They believe the chemical chronically overstimulates the receptors, leading to a steady increase in ApoC-111 levels and accumulation of triglycerides in the blood.

The findings suggest that THC-related increases in levels of ApoC-111 might be a "significant player" in the cardiac and cerebral problems observed in chronic marijuana users, Cadet's team writes in the journal article.