Top Things to Know: Use of Marijuana - Effect on Brain Health
Published: February 10, 2022
Prepared by Anne Leonard MPH, RN, FAHA, Senior Science and Medicine Advisor - Lead
- It has been estimated that about 183 million people around the world used marijuana in 2014 and 22 million met criteria for marijuana use disorder. According the U.S. Department of Health & Human Services, the proportion of persons aged 12 years and older, that used marijuana in the previous year increased from 11% in 2002 to 18% in 2019
- The use of marijuana is popular among adolescents and young adults – about 36% of 12th graders and 43% of college students having reported using marijuana in the last year according to survey results from the Monitoring the Future National Survey Results on Drug Use.
- According to the National Institute of Health, National Institute on Drug Abuse, “Marijuana Potency” (2020), there is evidence suggesting that the potency of cannabis products in the US, measured by the concentration of the primary psychoactive constituent of marijuana, ∆9-tetrahydrocannabinol (THC), has gradually increased from approximately 4% in 1995 to 15% in 2018.
- This scientific statement discusses cannabis and endocannabinoids, neurobiological actions of cannabis in animal models, effect of prenatal exposure to cannabinoid agonists, and the effects of marijuana use on human cognition.
- Acute use of marijuana is associated with impairment of working and episodic memory, behavioral disinhibition and impulsivity, which can affect performance in real-world activities. Early exposure to cannabis may have a negative effect on cognitive function.
- Several studies have described an association between cannabis use and increased risk of stroke. In addition, cigarette smoking is common in cannabis users and may be an important modifier or confounder of the relationship between cannabis use and stroke risk.
- Cannabis has vasoconstrictive effects. It also has a potential role in the development of cardiac pathology and atherosclerosis development. Cannabis use may also increase stroke risk by inducing reversible cerebral vasoconstriction syndrome
s(RCVS), or it may indirectly increase stroke risk. - Emerging evidence questions the widely accepted belief that marijuana is innocuous and suggests that cannabis, particularly THC, negatively affects brain health through direct and indirect mechanisms.
- Social media may emphasize a beneficial role for marijuana and the general population may perceive it as a harmless drug.
- Emerging evidence linking marijuana use to cardiovascular events and stroke as well as the potential and demonstrated drug-to-drug interactions between marijuana and medications commonly used in the general population call for caution and highlight the potential importance of active surveillance programs.
- Health care professionals and consumers should receive education on the potential beneficial and harmful effects associated with the use of marijuana, including the increased risk of stroke and cognitive decline.
- Health care professionals and patients should receive unbiased education about the potential consequences of medicinal, recreational, and illicit marijuana use on brain health, particularly when the exposure occurs during vulnerable vital periods.
- It may be important for professionals to monitor cognitive performance of marijuana users and review their medications to identify potential drug-to-drug interactions.
- Public health efforts should be considered to raise awareness about the potential negative effects associated with the use of marijuana in the general population.
Citation
Testai FD, Gorelick PB, Aparicio HJ, Filbey FM, Gonzalez R, Gottesman RF, Melis M, Piano MR, Rubino T, Song SY; on behalf of the American Heart Association Stroke Brain Health Science Subcommittee of the Stroke Council; Council on Arteriosclerosis, Thrombosis and Vascular Biology; Council on Cardiovascular and Stroke Nursing; Council on Lifestyle and Cardiometabolic Health; and Council on Peripheral Vascular Disease. Use of marijuana: effect on brain health: a scientific statement from the American Heart Association [published online ahead of print February 10, 2022]. Stroke. doi: 10.1161/STR.0000000000000396